If you want to see MORE REALISTIC TESTS for various insulation types from fiberglass to foam in a 2x4 wall, look here th-cam.com/play/PLHUfJmsprIcTVwSgCkTJnkinJSWrZY7DY.html
@@thewonderfulwonder1614 I will definitly do some version of that - numerous requests for wage tests. It may have toi wait till spring unless I can rig up a fume hood in my basement!
@@fernandoalcantar7907 Yes - have had plenty of requests for extensive Wago testing. Will definitely do it. May have to wait till spring since I cant do it inside due to the fumes.
I’d like to see a test that would simulate two space heaters running at the same time on a circuit of 14 gauge wire and see how long it takes for the wire to start toasting. Initially the wire can probably hold up but after say 10 to 12 hours that’s when it may start to fail. Many homes slap a 20 amp breaker on the 14 gauge wire incorrectly. So this is a real world scenario.
Twisted solid core wire can get brittle overtime, as well that it can be difficult for someone to take apart safely. If you want your wiring to last, no matter what you do, please leave an ample service loop if possible. You or the next electrician will be very grateful!
Agreed, but easier said than done when the box is small, the devices large, and many wires are in the box. And even if it is done, it will of course get shorter with each modification. Speaking as an electrician doing residential service work for about 20 years, not once did I ever see evidence of failure due to a lack of pre-twisting. The failures that typically happened: 1. Using quick-connectors on the back of devices, especially when used for feed-through applications. 2. Using side screws on a device and a screw came loose or wasn't tight enough to begin with (especially for feed through...). 3. Trying to fit 4+ wires into a wire nut, and one of them wasn't gripped by the threads in the wire nut. 2 or 3 wires tends to grip very well, without twisting.
Pretwisting makes it a PITA for the next guy for sure. No reason to do this unless you’re trying to force 5-6 conductors into one wire nut, which I always avoid.
I'm not surprised the wire nut didn't heat up appreciably. It really isn't carrying any current. Since the connection is actually the twisted wires, the wire nut serves only as an insulator.
The wire nut may not be carrying much current at all, but it's still screwed onto bare copper that's carrying 60+ Amps, so the impressive thing for me is that the wire itself was so cool. That's a testament to how efficient a conductor the twisted wire at the end was. I'm sure if you removed the wire nut and measured the twisted wire itself, you'd see pretty much the same thing. Seems like those twists were doing a pretty good job all by themselves (at least in a controlled environment where they can't come loose!)
agree, the twisted wires effectively double the conductor thickness an the wire nut's metal adds to this too. most the current wouldn't carry through other than being more concentrated at the entry/exit points
Funny - when I did this I never expected to get so many views. I did end up doing more realistic ones afterwards (14-2 in a 2x4 wall, 14-2 in a 2x4 wall embedded in insulation etc), but this video somehow is stuck in TH-cam's algorithm :).
Now if only somebody would put gasoline into a kerosene heater, to explore why that might not be a good idea? Lots of YT videos destroying things, but I have not seen that one yet. Sounds like an outdoor test, not near anything to be concerned about.
@ Well if they have done that test, I sure have not found it. But some channels seem to love destroying things. I recall some long time ago, some channel that likes to over-volt things until they can't take it anymore.
@ Well those videos get a lot of views. I occasionally do videos of this nature but limit them - I dont want this channel to be simply the burn things up channel.
Note the voltage drops at 8:22. That drop in voltage means the resistance decreased. In this setup, that can only mean that the wires are now touching before they get to the wirenut. In a voltage driven circuit (such as household power) at that point the current and power would have gone way up. Since I think we can assume that to get to that point the circuit protection has failed, at that point I would say the fire starts...
Good point about a real household circuit. One would sure hope currents never get to these levels. One commenter did point out how people upped fuse values in the old days if a fuse blew. So maybe back then sustained overcurrent may have been more common and there would have been the possibility of even the too large fuse saving the day when the wire shorted.
@@ElectromagneticVideos In the 50's, we replaced fuses with a few coins, screwing the bad fuse back in to hold them in. (After fixing the problem) Many people thought it was a permanent fix, but they caught on by the third or fourth rebuild. Other poor results are obvious by now, I hope.
@@hhn2002 it is. 15 amps is 15 amps. Also current depends on how much voltage you apply. There is no way to limit current to 15 amps at 120v with just the wire resistance.
Would be good to have a thermal imager rather than relying on touching the live wire (that is rigged to fail). This was a great video though, none the less!
@@dodgeguyz Based on suggestions like yours I did that in the "wire in fiberglass insulation" video I put up today: th-cam.com/video/Df7bAEdIILI/w-d-xo.html
Its not like touching that "live" wire is dangerous other than possible burns if its that ridiculously hot, but this is less than a volt for most of the test, so its doubtful that you would even feel a shock until the mid 20's or even 30v.
Keep in mind this experiment has the Romex in open air, which is reasonably good for letting heat escape, instead of passing through insulation in a wall cavity. Also he's only giving it several seconds to heat up. Don't use "didn't catch fire after 10 seconds in free air" to decide what wire gauge you will use inside walls! If the jacketed wires are warm on the outside of the jacket, they're hotter inside the jacket, and hotter still inside the wire insulation. And most of us hope our house wiring will last for decades. 6:50 watch the voltmeter climb: the resistance of copper wire increases with temperature. It's getting hotter.
Great comment and let me add to that. Any experiment - mine or someone else's, should not be taken as any encouragement or suggestion to use anything other than the approved wire for a certain application. Its just interesting to see very roughly what the safety margin might be.
I’m just a homeowner handyman, but I think you would have entirely different results if you used a length of 100 feet. A short 5 foot length is not meaningful and leads to incorrect assumptions
@@dustmaker1000He mentioned resistance around 6:30. 100’ sounds a bit long for household wiring unless you have a very big house. I’m trying to remember the longest run of my old house and I don’t think it was too much more than 50’. Perhaps 60’. 🤷🏻♀️
I once ran a 1500 watt space heater on a 100 ft 12 gauge extension cord that was wrapped around one of those plastic circular cord wrap things- so the cord was insulating itself from cooling off. I was just going to run it for 20 minutes so I thought it would be OK. I ended up falling asleep and when I awoke suddenly 5 hours or so later and ran out to the garage the whole garage smelled like hot plastic and the cord insulation was noticeably soft. It permanently changed the insulation on the outside of the extension cord
Wow - what a real and scary example of the damage that can occur from current overheating the plastic insulation. Interesting that the insulation was permanently changed. I what what chemical change was caused by the heat on the plastic.
@@ElectromagneticVideos I'll try to get a picture of it and send it to your email in the next few days. Still kind of spooks me a little bit. I had an InstantPot that had some kind thermal event too. It turned off before there was any damage to the counter but the IP was shot and wouldn't turn on
@@jeffa847 That would be interesting to see. I wonder if the instapot had some sort of internal thermal fusible link that saved the day after whatever failed.
@@Cheetahpuma-g2e 1500 watts on a 100 foot 12 gauge cord is OK according to all the charts I have ever seen. Some might call that basic electrical knowledge too. I have done it plenty of times even though I don't really like to and have felt a little warmth around the plugs when run for a long time but I never had problem with the rest of the cord getting hot - thus my original post pointing out that wound up it's a lot worse on the cord.
Oh nice. By zee way... where in the world did you come up with the idea of attaching a stinger to Romex, and various other things found within the confines of an electrician's van? This is quite a cool idea to play with.
@@DarthTwilight OK - I have to tell you the story! A year ago, I was at the local Habitat for Humanity ReStore and there was a vintage welder that had been marked down to $100 because it was not selling. I guess it not being DC was a deal breaker for most people. At $100 I couldn't resist and figured if I ever needed to weld something thicker than my MIG could handle it would be good to have. I also had at the back of my mind that it might be useful if I ever needed to do some high current tests. To put things in perspective, I'm an EE and always liked doing experiments of all kinds. It sat in my garage, and a year later (3 weeks ago) I was cleaning out some old extensions cords which I have always never trusted and thought - might be fun to see how bad they are before I throw them out. So I did (the video is there) and actually was impressed by the newer ones. That made me think - since I'm setup to do it, lets see what 14/2 can handle. Nothing very profound - just my idle curiosity and posted the video on my obscure little channel. I had no idea that it would get so much interest! Great thing is, many comments have been so thought provoking it had been way more fun that if I had just done the test and not posted it. The videos I have posted since then are all suggestions based on the 14/2 one.
@@waytospergtherebro Ok Grammer Nazi. I guess when you work for someone else, aka to earn a paycheck, you need to worry about spelling. Thanks for pointing that out. I'll remember next time that I need to worry about it.
Yes. The NEC has safety factor upon safety factor built-in. It’s apparent all across the code. Things can be stretched much past their code “limits” before catastrophe occurs.
@@alex43223 Very true! Although I was surprised how the safety factor becomes in some later experiments I did with 14/2 inside insulation as you might get in an outside wall.
So the wire hits 90C at 25A, but is that buried in insulation, or hanging in free air? And NEC actually prohibits its use above 80% of 15A, or 12A continuous.
@@stargazer7644 The NEC allows wire to be used at 100% of it's rating continuously, it's the OCPD that's limited to 3 hours of 100% rating, anything longer than that it has to be derated to 80%. Any load that could potentially be on more than 3 hours at a time is considered to be continuous. So you are correct in that the entire circuit is limited to 80% of the OCPD rating, but the wire itself is not the limiting factor. Also, you cannot use the 90C table unless every device the wire is landed on is also rated for 90 C, and nearly all circuit breakers are limited to 75C. In the absence of a temp rating on terminations or connections, you have to default to the 60C ampacity table for the cable. Which in this case for 14/2 is 15 amperes. Mike Holt has some excellent videos where it's explained in more detail.
A few years ago I was doing some welding, and absent-mindedly attached my grounding clamp to my bandsaw, and the return current found it's way through the 120 volt shop wiring. It lasted about 20 seconds at 75 amps before it let loose. Lots of charred insulation.
@@ElectromagneticVideos I was lucky- most of the current path was 12 gauge, and it survived fine. There was only one section of 14ga. that I had to replace
You will Be suppressed how often this happens in workshops. Especially with the older non inverter welders. The return path ends up going down the earth ( ground wire for you guys). This cable gets so hot it melts the insulation on everything. The new inverter welders tend to run earth free on the outputs and is less of a problem, ( I think this is the case but never actually tested it). If your work is touching the building steelwork make sure you have a good return connection
@@johnwarwick4105 I didnt know it was a common thing. Surprising that someone didnt make a current sense relay module for the welder ground/earth wire that would disconnect power the instant that happened. Could have have prevented what I'm sure were costly accidents. I'll bet your right about the inverter ones (or at least some of them) having. I have done a fair amount of switching power supply design, and many have no electrical connection between primary and secondary. There might be a regulatory requirement for a ground connection perhaps for some perceived safety issue or RF suppression although I'll bet many on online sites might not exactly be built to adhere to any standards!
As a 66 year old Master Electrician I appreciated your test. It helps to see the tolerances of the material we use in the field so we have a better foundation to talk to our customers. We all go through the classes and books but to actually see the breakdown of the conductor is impressive. This gives me more confidence in the load carrying capacity of house wiring especially with today's insulations which raise or lower the load capacity. Thanks ;)
I glad you found it useful. I did a few other videos with 14/2 in 2x4 walls with various types of insulation such as fiberglass and foam. I am actually a bit concerned about situations like a fully loaded cable between piles of insulation in hot attic in the summer running an air conditioner. I would probably ask to have the wire increase in size by a gauge or so in situations like that. I'm an electrical engineer so I don't get to see the real-world examples of things the way you do (and also usually deal with low power RF signals most of the time). Have you ever seen NMD or other cable damaged by running close to the max rated currents when situated in the middle of insulation in an already hot environment? Any sense from your experience how close to the edge of the safety margin we are with modern cable and insulation?
@@ElectromagneticVideos Well in the field we follow the NEC which requires no more than 80% load on any circuit and manufacturer recommendation for dedicated circuits for apparatus like dishwashers, A/C's etc. so for the most part we do not see break downs like your test unless the work is done by unlicensed people like Home owners who simply wire to make things work not considering potential consequences. However with the advent of more home generation equipment and EVA's and other new apparatus, I can see more overloads and fires with misapplication and improper wiring of such equipment. I will say I see a lot of interruptions and breakdowns using these Mexican made receptacles, switches and foreign made new light fixtures which do not have the same oversight in manufacturing that used to be the standard in US made parts. Especially after NAFTA which made foreign made material the standard in the construction industry iMHO
What I would love to see is more test videos on Service Equipment in todays environment using ARC FAULT devices. I see these products not proven in todays world. But time will tell. Thanks again.
@@carylamari6546 I actually also have seen scary stuff done by homeowners. I have a buddy who does home renovations on the side and you wouldn't believe what was in one of his projects - the previous owner (and I am embarrassed to have to say was an engineer!) used everything from speaker wire to coax to hook up additional light fixtures and outlets. We spent a fair amount of time searching through things just to find the hidden things to point the electrician to to remove or replace. I wish I had been making video back then. What an example of what not to do! The plumbing was equally "interesting". Interesting you mention home generation and things like EVs. I will be adding some (used) solar panels to my house and have been researching the often not too to well publicized specs of the breaker panels when attached to loads + generation sources at the same time as the grid. I can sure see how things can go wrong if the panel bus rating is less than the sum of power sources if large loads are attached in spite of everything having properly rated breakers. And yeah - general cheapening and lower quality parts does not help!
@@carylamari6546 Well I just came across some Cutler-Hammer Arc Fault receptacles on sale, so I will be trying to see what sorts of arcs can trip them. Still have to figure out how to do it - probably with everything running though either a gfci or isolation transformer (I have kw sized one) and making the arc using a switch with poor snap action or some sort of touching cables current limited buy a light bulb ... . So Arc Fault stuff to come in the future!
I worked in cable, when foreign voltage melted our lines, it was always at the splice points of the tap or the ground block. We could cut the melted part off and the cable would still be fine. You need to test a longer length circuit with multiple splice types for an accurate test.
Glad you liked it but things are not as good as in this video when in a real wall - did some later videos where I built a section of 2x4 wall with insulation around the wire. The safety margin goes down quite a bit as expected.
@@ElectromagneticVideos I would completely expect that. I'm a communications engineer, and essentially what you are suggesting relates to heat dissipation, due to the resistance of the wire, it develops into heat, and as long as that heat can be dissipated, the wire is fine, same deal with a forced air electric heater. If the fan quits, that wire is going to burn up unless it is protected with a heat sensor to shut it down of course. If you don't have a thermal camera, they are great investments, as you can find heat and cold leaks in your house, and they are awesome for troubleshooting circuit boards and defective components.
@@jimturpin I actually did get a thermal camera for the later tests - great toy to have! Communications Engineer? What do you do - I used to be involved in HF/VHF/UHF comms. Now I'm more in the faint signals detection type of stuff in the microwave bands. HF was great fun - nothing cooler than transmitting vast distances with a few 100w.
Good video! As you started reviewing the wire nut I realized that most copper beyond the initial contacting twist also forms a heatsink for the bit of copper at that first mating twist, thereby helping to keep it from being the point of heat failure. Very nice little safety bonus I had never thought of before.
Thanks! Yes - as old and simple as the wire nut is, it is a remarkably effective device. I have tested other connectors in later videos - some are remarkably effective and arguably easier to use or disconnect, but nonce connects better than a properly used wire nut.
Growing up I remember just sticking in ends to see if it fits whatever it was I was trying to use and if it fit it was the right one. With that said, I’m very impressed I’ve never set a fire but I definitely gave my kids a live performance like you did here, showing how a cord will catch fire if it’s not meant for the device or the devices board will fry ruining it.
Always great to expose kids to science experiments if done with the appropriate safety precautions. Most kids naturally love finding how things work - at least until some of the textbooks used in school drive any intensest in the subject away.
Interesting that NEC requires the wire nuts are rated at a higher temperature than the cable. I wonder if its because of an assumption that they might be a poor connection and more heat generated?
@@ElectromagneticVideos UL's connector standards try to assume worst case scenarios, there are some different categories too like usage in explosive atmospheres, Used to be that wire nuts didn't have a current rating at all and it was tied to ire size ampacity. But the basic connector standard now says 20 amps. A lot of problems arose when there was a major push for WAGO connectors and adopting IEC standards, but the whole IEC standards are a joke! IEC does no testing and doesn't require any. 98% of IEC "certifications" are "self certified" by the manufacturer. Basically this means that the manufacturer attests to their device meeting the engineering standards. They use a statistical based "verification" process, meaning they don't question anything unless there are a very high percentage of complaints. In extremely rare circumstance, they may request 3rd party testing. Manufacturers are not even required to test or keep testing records, I've worked in industry for man years and IEC certified stuff is junk! WAGOs tyoically say 32 amps on them and also has a UL certification. But the UL rating is 20 amps, 32 amps is the IEC rating! The Japanese rating on these is only 20 amps also. And strangely enough, Japan's residential voltage is 100 volts! WAGOs have been used all over Europe but they use 230-240 volts as the standard residential voltage. So on average, the typical currents for the same appliances, lighting, etc. operate at half the current of the same stuff in North America. So the odds of a statically significant number of failures is low and complaints are minimal. But all you need to do is take apart a WAGO to know it's not a good connection! Part of the problem today is that most installers think certifications are equal. But the truth is that these standards ae apples tp oranges comparisons! The inherent resistance of WAGO connectors is multiple times that of wire nuts. But because the dissipated heating is "I squared R" , twice the current is 4 times the heat dissipated. For the residential wiring installer, they just know that WAGOs are easy to use. Most of these installers have little formal electrical theory training and very few states require any kind of certification. I refuse to call these installers, electricians! They know how to connect things up and mist know the code, but few really understand the theory, Kinda like the cable installer guy who has no idea how the modem works! I find it interesting that WAGO markets to contractors but not engineers in the US. As an electrical engineer I would never approve or specify these connectors, I think these are probably OK for low current applications like LED lighting fixtures, but I would never use these in typical residential wiring. '
just an FYI the adoption of twisting wires before putting on the connector came from the use of Marr connectors which had a small screw in the side which held the two wires together. if you didn't twist the wires then they became flattened as you tighten the screw and there is a lot of chance the cross-section area of The wire would become very reduced and over a period of time of heating and cooling the Matt connector would loosen off. Ken
The voltage suddenly dropped to nearly half at the point that the insulation began melting even as the copper heated and began increasing its resistance. Then it began rising again from the lower value. I suspect a short part way along the cable, which reduced the impact further down the line (eg: at the far connector).
Your welcome! I did more realistic tests with the 14-2 in 2x4 wall surrounded by various types of insulation. Not as exciting but a bit of an eye-opener as to how the safety margin drops drastically with insulation. Here is the link if you interested: th-cam.com/play/PLHUfJmsprIcTVwSgCkTJnkinJSWrZY7DY.html
When I bought my home 10 years ago most of the house was wired with 10ga cloth and vinyl wrapped wiring, with some scattered modern 12/3 for new outlets added, and they added 10/3 to dedicated outlets to each window air conditioner outlet. The worst overload was the living room which had four lamps, each with a 100w bulb and run off a single run of 12/2 w/o any ground, which also included the front porch lights and two outside outlets and four single bulb fixtures in the basement below, each with 100w bulbs. It showed no sign of any failures but I did run new 12/3 runs to each outlet, one to the porch and two to the basement lights on that side when I tossed the old screw in fuses for a new breaker panel. The old wiring was plastic insulated wires in some sort of silver cloth wrap. A few bulbs in the basement still have that wiring but little by little I'm replacing those fixtures with LED units, and for now, every bulb in the house is LED.
I lived in a few houses with messes like that. An some that included silver cloth platic wireing that I think came just before NMD. Sounds like your a bit like me - every home I lived in was safer when I moved out than when I moved in.
that doesn't seem overloaded. 12/2 can handle 1900w without issue and upto 2400W for non continuous loads, if it was overloaded it would continuously flip the breaker
I think you do not understand electrical math? The chance you had 400 watts of lighting and then plugging in a 1500 watt vacuum is unlikely to trip the breaker.
Honestly this is a terrible test. it gives people the false sense of safety on residential wiring. no one should put 60 amps at 120v AC through a 14/2 wire. he had it at 2v before the coating started to melt. your house doesn't run on 2v AC..
This was interesting to see, and one should keep in mind this is in open-air. If you had a fan blowing on it, it would go higher, and if you put building insulation around it, it would heat up much faster and support less current. Finally, the fact it burned at the corner is also a clue, the thinner the wire is at a particular location, such as a bend or pinch-point, the greater the resistance there, and the more heat generated. So, to compensate for all of those factors and more, it is rated for 15A max to ensure safety.
Very good point. I actually did follow up experiments with the 14/2 in a fake 2x4 wall filled with various types of insulation and the results are exactly as you predict.
Glad you liked it! Thats the perfect takeaway from the video! What has surprised me is that apparently some people do upsize breakers - a really dangerous thing to do! I did some later videos with wire inside walls filled with insulation - it doesn't survive nearly so well in that more realistic situation.
My old 1956 house used 15 gauge wire with black woven insulation. Would be interesting to see how much that would take until flames. A few of the breakers were 20 amps and it hadn't burned down.
@Kelly Harbeson 14 gauge wire is far from rarely used. It's the standard wire for residential homes. At least around here. 12 wire is for 20 amp circuits where required, like bathrooms and kitchens. When someone at work tells me to start pulling wires, I reach for the 14/2 unless told otherwise.
There are plenty of limited current circuits in commercial work, and wether you're using THHN in FMC or MC in commercial, or Romex for residential, 14 gauge wire is 14 gauge wire. However, you're right, you really hardly ever use 14 in commercial.
@@fredmauck6934 100% this. My parents house has what appears to be a 500A main panel because they are all 30-40A fuses. Even with the oversized fuses the air conditioner will trip the fuse if the microwave is already on.
@Kelly Harbeson I don't know where you live, but here where I live everything but the kitchen is 14 gauge. The kitchen obviously needs more capacity so it gets 12 gauge. Some people don't like handing 12 gauge( harder to bend and also to manipulate in the boxes.
I recently left a wheelchair manufacturing outfit and part of my job was testing the electronics modules. The motors on ours were fed with No. 10 stranded wire, and if you stall the chair against a block and firewall the joystick, they would pull over 200A for a short time, which amounts to approx 100A per wire to the motors. No ill damage occurs.
The key is "for a short time". Not long enough to heat up enough. I assume the system has some sort of current limiting in the electronics in case of an extended stall?
It not as scary as it looks! Because the end is shorted there are only a few volts needed across the conductors to push those levels of current though and generate the restive heating effects. I wouldn't be touching them if it was live 120V!
The dissipated watts per foot along the wire would be the same for a given current, so for the same current the same rise in temperature would occur over the length of the wire. There is a corresponding per foot voltage drop (which in these tests is the voltage I put across the wire). So at the end of 50ft you would get a resulting lowering of the voltage presented to the load. At rated current on a typical branch circuit, I believe the code says no more than 3% drop is allowed. So for this type of overload on a long wire you might get perhaps a 10% drop lowering the 120V the load sees to 110V or less. If the load is resistive that would drop the current by roughly the same percentage. But if it is a constant power load like a electronic power supply or induction motor, the load will draw roughly that much percent more current making the situation even worse. Of course in a real situation the wire also goes though 2 by 4s, insulation etc probably making it hot at somewhat lower currents.
@@dirkdiggler2052 I think you would need a flux capacitor for that :) Actually you bring up a great point - it is really hard to keep electronics cool in a vacuum. Infrared radiation and conduction of heat to other parts of the structure is the only way to get rid of heat. I know the Soviets actually used sealed boxes with gas inside holding their electronics to help with cooling. I wish I had a vacuum chamber to try 14/2 in a vacuum and see how low a current would melt it.
Super video! I see a few suggested a thermal imager! Also would be cool (actually hot) to see actual degrees temperature along with your observations as to touching and explains the heat! Again, enjoyed the video!
Glad you enjoyed it. I'm getting more and more tempted to get a thermal imager. I do have a thermocouple temperature probe on order. Now that I think of it, I wonder if my IR temperature gun would work or if the wire is too narrow for it.
This is a short term acute test. High temps over time will break down insulation, which is a major problem, especially when the wire is within insulation or otherwise contained in an unventilated space.
Yes! I have also seen the insulation on cable that is 30/40/50? years old get brittle, particularity where outer plastic has been removed. Seen similar aging effect on plastic in vintage appliances. I wonder if modern plastics have improved and are less prone to that?
Thanks - glad you liked it! Yeah - maybe I need something at the beginning of each video saying "don't try this at home". Do a have warning at the end ....
@@ElectromagneticVideos yes, I saw the warning at the end. I noticed you stated the 14 ga wire was only supposed to carry 12 amps in a home situation. You did a great job. Thanks again.
@@thomasglessner6067 I really appreciate that Thomas! You know what was a disconcerting surprise to me - in some of the videos that came after this one I built a 2x4 wall section and did similar things with the 14/2 inside between insulation. The safety margin drops so much in that situation that if I was building a new house today, I would make sure 12/2 was used at least everywhere it goes though insulated outer walls or (worse) hot insulated attics.
Yes - thats a huge problem with plastics over time. I have come across old 14-2 where the plastic is brittle and shatters where it enters a junction box. Unclear if modern plastics are better.
I'm curious what the resistance is for the length of wire you used and if you tried a 30', 40', and 50' length of wire if there would be any difference in the results.
Well for a given current which in a normal situation is determined by whatever the load is, the heat emitted per foot of cable does not change if the cable is made longer or shorter. Your right the resistance goes up for a longer cable, but the result heat is distributed over the longer length and the temperature rise remains unchanged. What does make a difference is if the cable in a wall filled with insulation and as expected things do go bad at a lower current. I did do a FAQ video here if your interested in more details: th-cam.com/video/CP3-jcpzZeI/w-d-xo.html
At 2vac 60amps the wire is only pulling 114watts, the wire is rated at 1,710watts 120vac at 15amps. Try this experiment again but with a load that doesn't short out the voltage :) still a very educational video!
It doesn't make any difference. At 60 amps this cable will always drop two volts and dissipate 114 watts. If you jack the voltage up to 120 and connect four electric heaters to draw 60 amps, the cable gets two volts and the heaters will get 118 volts and dissipate 7080 watts.
I'm a retired Engineering Technician, which means I built prototypes in the R&D dept. This was back in the day of wire wrap prototyping. I got curious one day and connected a length of AWG 28 wire (Kynar wire wrap wire.) to a Kepco 20V 50A power supply to see how much it would take to "fuse" it (melt it). It started to glow at around 23A and finally melted at 27 amps. Not too bad for such a tiny wire. Wire can handle quite a bit more than one would think, it's the wrapping material that usually gives out before the wire will. If you were to repeat this test to try to "fuse" a single wire, I doubt your welder could do it TBH.
I remember wire wrap prototyping! Also have a vintage Motorola TV from the early 70s where wires between circuit boards were wire wrapped. That TV was remarkably prone to intermittent connections at the wire wrap point - I'm guess int was due to a poor manufacturing process since wire-wrap had a reputation for making good connections as far as I know. (Am I wrong?) It is remarkable how much current a wire can handle beyond what what its rated for.: 20+ amps for #28 sure sounds remarkable. As far as fusing single wires - the antique welder is more powerful than you thinks. In more recent tests were we tested some connectors (Wagos and others), when we exposed #14 bare wire to over 200A, the wire melted and broke before the connector did in some cases (!). But - it take 5 to ten seconds to do it. So you prediction would have been correct with slightly thicker wire.
@@ElectromagneticVideos In my experience with wire wrap, there was never any issue with reliability (we had systems in service for >10 years). This was due to the fact that the wire was usually wrapped around a square post around 5 turns. So each turn had 4 corner contact points. The only issue was potential shorts if you bent the post as they were like a half inch long. We used it for both analog and digital prototyping. What was great about it was easy rework if the design needed changing, which it often did in early development. As far as wire testing, "fusing" is not really a valid test, other than to see how far you can push it. It serves no real world application. A 150A service main breaker would trip long before it would melt a 12 AWG wire, depending on whether it was a magnetic breaker or thermal. That's one thing I doubt many DIYers know about, the different types of breakers. That's kinda getting in the weeds.
@@markh.7650 So you have confirmed the the reputation that I thought wire wrap had - good quality connections. I did a little wire wrapping in the 70s and never has any issues - but that was all for short term hobby stuff when I was a kid/teenager. I wonder how Motorola messed up when they wire wrapped those TVs. My guess is maybe after wiring many TVs, the powered wire wrap guns wore in some way and became less effective. Or the posts they uses didnt have sharp enough edges. Probably didnt matter much since that was not too long before Japanese imports essentially ended TV production in Canada and the US.
I had a space heater at work under my desk and during the day while I was there the fan failed and the heater caught on fire. I unplugged it and threw it out. What would have happened if I had been away from my desk?
Thats a scary scenario. These days they are supposed to have thermal cutout fuses or fusible links to prevent a fire in situations like that, but clearly one cant those protective devices to always work.
This video reminds me of some scary pages on the subject of Federal Pacific Electric breaker panels. Despite several design revisions, independent tests have demonstrated that the circuit breakers in these panels are prone to failing to trip.
Yes - I have read about them too. Its hard to imagine how much worse it could be with those breakers. While the simple heating and melting of the plastic wire insulation would be similar if someone plugged in too big/many loads like heaters, once a short did occur in the cable as a result of the plastic melting the AC power system would not be inherently current limited to a few hundred amps like the welder is. You could easily expect 1000s of amps flowing and the copper wire vaporizing. Hopefully the main panel breaker would trip fast enough to prevent a more catastrophic result - no idea if the main breakers have the same failing to trip problems....
I am actually hoping to have time to try something like that this weekend. I'm planning to use two 2x4s to make a simulated 16" OC section of stud wall with fiberglass insulation. Will also be interesting to see what happens to the wire in the holes in the 2x4s.
@@ElectromagneticVideos please make a video with different types of conduit (plastic and metal) to see how much heat is dissipated. I think with a metal conduit inside a brick wall you can easily overcurrent 2 times without issues.
I'm so glad you made this video. I just had an argument with some moron and he was freaking out because someone else put a 20 amp breaker on 14/2 ... i was like Dude you're safe. for safety concerns they often quadruple and quintuple rate the wires for worst case scenarios. let the breakers do their job. they don't cut the ratings so close for safety reasons.
You know - even if it were just for insurance reasons the breaker should be switched. And some breaker have quite a large margin of error for when they trip. But take a look at some of the followup videos to this one - particularly the ones with 14/2 though insulation. With a well insulated wall there really is no room for comfort. So much so that if I were having a house built today, I would get 12/2 for the 15A circuits - I was not expecting that.
@@ElectromagneticVideos well that’s the code. 14/2 for lights and 12/2 for outlets. Because outlets typically have more shit plugged into them. Not a lot of people overload lights
@@chuckholmes2075 Interestingly I don't think 12/2 is required for outlets yet here (in Ontario) but I could be wrong. Certainly good to hear its in the code elsewhere.
In military comm school, you have to build a radio set using no solder, just mechanical connections between components - twisting the leads together 3 full turns seems to work well
Wow - building a radio like that must have been a great experience. I'm guessing it was more than a simple crystal set - so amplified crystal radio? regenerative radio? I'm guessing superhet would have too many connections to build like that?
I think testing it at the mains voltages(120v/220v)should give more realistic observation as the cable will be stressed both at high voltage and high amperage imitating the actual household scenario
@@AgentOffice Doesnt matter? Be caution! Its about the devices wattage. if u have for example an audio amp that will deliver a continu 600w of power, under a supply battery of 12v, that wire will explode at 50A.. u cant exceed max 10A.. its all about the delivered watt and your pressure, this wire can handle a device of max 100w
@@AgentOffice yes, the fuck it does… voltage makes a big difference plug 120 V lights into 240 V circuit. and you tell me what happens! But I will insist for you not to because of how destructive and potentially dangerous it could be!
Sweet video. Intentional electrical fires in the garage has been a pastime of mine since it was my parents complaining about the smell. Would be interesting to see how different environments effects this, such as bundled conductors, passing through studs, different conduit types, or buried in insulation. I’ll have to do some tests of my own.
Go for it! I'm going to try 14/2 though fiberglass insulation between studs and also covered in spray foam which should really hold in the heat and make cable insulation melt at lower currents. Conduit would be really interesting. I dont really trust the PVC conduit - if you try it please let me know!
@@assassinlexx1993 And if the kettle itself is old with blades on the plug being tarnished, put that in your cheap receptacle and the combination is even worse!
I really should do some testing of that sort of thing in a video. I'm sure it would create some heated discussions - there seems to be a huge divide between electricians with some adamantly advocating pre-twisitng wires and others being against it.
Excellent video, and I am totally amused by the 'experts' who keep commenting you have it all wrong... you need 120 Volts. The wire is 'rated' for 1,800 W, (120 V x 15 A). They conveniently leave out the 'R' parameter of Ohms Law. The only thing that matters is I and R to determine P (the heat energy over the length of the wire). Nobody cares about _supply_ voltage. The topic of the video is _voltage drop_ across the wire, hence the low voltage, which results in high current, due to low resistance and therefore significant heat (Watts). The formula for this test is *_I² x R = P_*
Yes - I reply to the people who nicely express they confusion about that and try to explain, but totally ignore the "your an idiot" type comments. You can have a discussion with those types. You certainly explain it very nicely. The legitimate complaint some have mentioned is the cable is in open air. A number of followup videos are with the cable in a 2x4 wall section with different types of insulation. The safety margin sure goes down!
Good test but time also plays an very important role. I tried the same thing with a 0,75 square mm (typical lamp wire size) wire and it could do 100A for about 10 seconds. Impressive but 10A for an hour or two will also melt it.
@SomeDumUsrName he wasn't talking about 14g wire, from what I can tell. He said 0.75 square mm wire, which I'll assume is the common way wire size would be measured outside america. (I'm used to awg so idk)
Very bad example I would not call it a test. Use the formula not the amp probe. The resistance is for all practical purpose is 0 If you look on a breaker 15 Amps or 20 Amps they will read 10,000 Amps RSM 120 volts/0=( dead short) And also with # 14 which is rated at 15 amps. You are not suppose to have but 80% continuous . The capacity of a conductor is based on the insulation.
I was hoping this experiment would tell me what amps were dangerous with household systems. However it’s not obvious whether what matters is amps or watts. I’m guessing it’s amps in the wires rather than watts in the whole circuit. My mcb s are 15amp. The plugs and sockets and wiring are rated 10 amps. With a double socket it would be possible to have 20 amps going round with a kettle and toaster and maybe something else.
i did a similar test with new wire to K&T wiring, and it actually failed in order from new to old, though the K&T never failed. it took 90 A never failing (it did get very hot, and oozed rubber out of the cloth)
K&T generally is so far apart that it is considered 1 wire suspended in air, and can dissipate more heat into the surrounding air than the two wires adjacent to each other inside the sheath shown here. It's all about if the wire can dissipate enough heat to avoid burning the insulation.
90A! Wow. Its held by ceramic insulators, right - they didnt crack when it got hot? I had heard it was great as long as it didnt get messed up by modern upgrades.
@@ElectromagneticVideos didn't crack or anything, and it didn't even get that hot, i could put my hand on the wire, the 1940's "Romex" style wire held up very well too, until the outer insulation cooked til' it became conductive carbon and started glowing. Yes, it is fantastic so long as it is not covered by insulation and doesn't get over loaded by dangerous modern additions, usually by homeowners that do not know what they're doing. i have actually wired one of my storage shed's with it, and used an 1800's fuse board that i built myself. works fantastic. I'll one day do a video on it
@@gtb81. Incredible that did vintage setup like that! I hope you video it - I just subscribed to your channel so I dont miss it. Just watched the vintage lightbulb video!
Thanks for this video. I now understand why our local code limits voltage drop on cables to 3%. In extra long cable the heating effect would be even greater and so the current capacity even less.
Yes - the longer the cable, the more total heat generated for given current and with a proportionally grater voltage drop. It is worth pointing out the heat generated per foot depends on the current (and resistance per foot of the wire) so the extra heat generated is distributed of the longer length and the temperature rise is the same regardless of length.
Not at all. If voltage drops, current drops too. To long wires would make the installation simply not usable. The breaker will trip if the current exceeds 15 amps. The wire is designed to handle 15 amps safely and should not melt even when it is 1 mile long, but how your 120 v bulb or heater can work if there are 20 volts coming into it?
It would not change. The heating per foot is from the current running though the wires, not the voltage between them. So only the value of the current matters. Now if it was hooked up to a real 120V circuit with a load at the other end, one difference would be that there would be a circuit breaker in the circuit, and the moment the plastic insulation melted to the point that the wires in the cable shorted, the breaker would trip and cut the power. So it would be less dramatic than in this test where the current keeps flowing after the cable shorts internally.
Seems to me that the wire nut never saw more than 70 amps, if that. A short circuit apparently occurred in the first third of the wire as the insulation melted.
rsA couple of things. I'm not sure the wire nut had the full 60 amps at all. it looked to me as though the wire had melted and shorted at some point, diverting the current away from the wire nut. Nevertheless, it did hold up pretty well which is good news. The real 'safe' current carrying capacity depends on more than the wire itself, but also in all the situations in which it might be installed, according to regs etc. Even a much lower current will cause a failure if the wire isn't able to dissipate the energy at a temperature below the plastic melting point. That's why extension leads should always be completely uncoiled, regardless of the length actually needed for a given application. I've seen whole rolls of extension cables drums fuse into a solid mass of plastic - even when used well within the rated capacity of the wires. I worry that people watching your videos might come to an unsafe conclusion, thinking that a 15 amp wire (which as you say is only rated for 12 amps continuous), might actually handle 20 or so amps - way below the 60 amps you demonstrated to be a problem. I once witnessed a house fire in a house near me. All put put fairly quickly once the dire department showed up. On investigating the cause, it turned out they had trapped a thin brown two wire extension cord under the leg of a desk. Even though the load was way under the limit for the wire, being trapped in a tight space, the wire slowly got hotter and hotter until the wood of the desk leg itself ignited. If the wire had shorted, it would have presumably tripped a breaker and not started a fire. Interesting video, but of you can, please make it clear that no-one should run wires anywhare near their maximum continuous current ratings. Even if the wire nuts hold up. Cheers
"I've seen whole rolls of extension cables drums fuse into a solid mass of plastic - even when used well within the rated capacity of the wires." I'll bet may extension cords are in use spooked up like that. Can sure see how the heat can build up dangerously. Your point about warning people is well taken. I do say it in the description - would hope people read it.
60amp on 2v.. but if u have a supply of 12v and having a current draw of 60amp, that cable will explode in a instant.. its all about watts.. people should do the math..
I would guess almost indefinitely unless sandwiched between thick thermal insulation. There is a significant margin of safety as there should be. Many circuit breakers can be quite inaccurate as to what current it takes to trip them and after how long. I have seen specs for some that allow a 2x overcurrent for up to half an hour before tripping. So the #14 should be able to survive a 2x overload (2x15A=30A) for half an hour without failing and it seems to be able to. Of course that should not be taken to means its OK to use #14 for 30A!
Wow, that demonstration really lets you appreciate the codes and the wiring that we have in place in the United States. Barring any malfunction of a breaker, any short circuit in the system will immediately be terminated and I guess the biggest danger in the house that’s wired to code is WHAT THE HUMANS WHO LIVE THERE DO TO CREATE A PROBLEM😳 Thank you for this demonstration. Wonderful. Makes me feel good about the home I live in.
Its great to see how large the margin of safety is! But is not always as good as in this video. Take a look here at a later video I did th-cam.com/video/lFdSXTKsKwA/w-d-xo.html - one of a number where the wire was in between insulation in a wall. As expected, melts at lower currents and I would actually use a larger than code required wire in places like a hot attic if I was having a new house built - or even anywhere where the wire is embedded in insulation. . .
In the real world yes, a longer wire increases the voltage drop which then further increases the current. For this test its irrelevent. Resistance and heat dissapation should increase equally as wire length increases.
@@insylem one would think that for uniform wire what matters for failure/melting is wattage dissipated per unit length. Since resistance grows linearly with length, voltage drop and total wattage grows linearly with length, and wattage per unit length remain constant
@@otov100 in the real world the shorter wire isn't more robust though. A 250ft wire will fail at the same current as a 2ft wire. That larger voltage drop is spread over a longer distance so the heating per ft stays the same. But you do end up with much less usable voltage at the end
Best most reliable connection is to strip wires about 7/8" then pretwist using long linesmen pliers, trim ends of wire even, install wire nut, twist with linesmen pliers until at least one full turn of insulation , Tape with a few wraps if quality tape.
@@ElectromagneticVideos Started out in a large slaughterhouse that between all the vibrating crushers, vibrating screens, high speed centrifuges and nightly high pressure wash down had to tape every wire nut. Opened up junction boxes that had 4" of water and energized 240 volt submerged well taped wire nuts that still worked. If not taped would have grounded out. Also always taped every device ( switches & receptacles ). Can never remember ever having a wire come loose on a screw that had a few wraps if quality electrical tape. Pays to go the extra mile.
@@JohnThomas-lq5qp That must have been interesting. I am amazed that wire nuts did so well in such a wet environment even with careful taping like that. Equally impressive surviving longer term vibration. I once had to vibration certify an embedded device - it was staggering how quite mild vibration will eat through insulation or anything else that was rubbing over a few days. You certainly convinced me that taping a wire nut is the thing to do. By the way - the best thing about this video for me has been comments like yours. So interesting to hear things like that!
Your welcome! However, please be aware that this is a somewhat unrealistic - the cable in normally confined in walls with much less air flow, and often surrounded by insulation. Under those real circumstances, it fails with considerably lower currents. Here a link to those tests: th-cam.com/play/PLHUfJmsprIcTVwSgCkTJnkinJSWrZY7DY.html
That is a fun video to watch. However, I would caution viewers of this video from assuming that Romex/NM-B wiring has "lots of built in margin" and can safely be pushed beyond its rated ampacity limits. My understanding of the electrical code is that it is acceptable and allowed to bury NM-B wiring under insulation, inside walls and attic spaces. Therefore, it is not uncommon for the wire to experience much higher thermal resistance (compared to being exposed to free air), and consequently much higher temperature rise, for a given current level. For example, fully encasing an NM-B wire inside "R13" rated insulation should theoretically increase the thermal resistance and temperature rise by a factor of approximately 13, compared to having the wire free standing in air. Since thermal power dissipation per unit length (and therefore temperature rise) is proportional to current squared (ex: P = I^2 * R), encasing the NM-B wire in R13 insulation is probably going to result in a somewhat similar temperature rise to running the wire at 3.6x of the rated current, but in a free air environment. In other words, for 14/2 Romex/NM-B wire, which is normally rated for 15 Amps maximum, when fully encased in R13 insulation, may experience about as much temperature rise as it did in this video, when he was pushing the wire to approximately 50-60 Amps (since 15 * 3.6 = 54A) in free air. It should also be noted that most electrical related fires probably originate from the electrical connections at the ends of the wires. Thermal cycling from repeated heating/cooling often causes loosening of the screw terminals and other interconnecting devices over time. This is due to the thermal expansion coefficient of the metals, causing them to grow and shrink dimensionally as they heat and cool. The subsequent loosening of the interconnection causes increases in resistance of the connections, which then brings even more heating and more severe subsequent thermal cycling degradation. Additionally, bare copper and brass love to oxidize freely in air, which causes a buildup of oxide layer on the surface of the interfaces, leading to more resistance (and therefore much higher heating) over time. Ideally, manufacturers of wire interconnects would get their act together and start making better quality connectors, which have high safety margin, redundancy of contacts and retention mechanisms, along with active strong spring retention force, rather than single fixed screw/bolt terminal connections, which often loosen over time due to thermal cycling.
What a fabulous summary of all the concerns and considerations! Thanks for taking the time to write it. Your point regarding the effects of insulation: Assuming I have time, I am planning to do a similar informal test of 14/2 in an insulated wall section tomorrow. It may be a less dramatic video but will be interesting to see what happens.
I don't buy how hot type NM-B cable can get inside a R13 insulation. When they switched from NM cable in early 1980's the type TW insulation was only good for 60 degrees C. Type MN-B has type THWN insulation and rated for 75 degrees C . Have removed thousands of feet of mostly older type NM cable from homes & businesses and never came across signs of overheating on cable jacket and the individual conductor insulation. Now that the NEC requires all screws & bolts used to secure wires must be done with a torque driver or torque wrench greatly improving reliability. At an IAEI continuing class the instructor told us that UL went around the country and rounded up hundreds if not thousands of existing device and took them back to test facility to check for proper torquing. Think less then 35% had the proper torque , 20 % excessive torque and remainder too low torque. Told us that over torquing is just as bad as not enough torque. Out of they over 100 attendees that night less then 10% sorry to say owned a torque driver. Before retiring I worked at a rich fortune 500 company who refused to purchase torque drivers, IR camera & circuit tracers.
@@JohnThomas-lq5qp That survey of devices where only 1/3 were correctly torqued is telling. Would be interesting to know how many of them had signs of problems as a result. When you started, I'm guessing torque to a spec was not a thing, other than perhaps really hi powered stuff. I wonder when it started becoming common if not required.
@@JohnThomas-lq5qp you never came across overheated jackets on old NM wiring? Really. I find this fascinating because I have seen it quite a bit. I've even seen it in my old home (built early 1970s) and had to replace it. All the NM was in attic and experienced very high heat for decades plus current draw from kitchen appliances.
@@theelite1x721987 I started out doing residential work first few years then after 15 years seldom did any residential work due to fortunate enough to get tons of commercial work. Myself and another 10th grade industrial shop Vo Tech student rewired a 3 story row house by our selves. Took 250 man hours to rip up floor boards, chisel out paths in plaster over brick walls, etc. Did a lot of machine shops, tool & die shops and injection molding plants but would do work in owners, friends & relative homes. Even was lucky enough to do some electrical work in a 300 year old Quaker meeting house, newspaper, hospital and some 200 year old homes. I upgraded at least 30 or 40 old row houses that only had a 30 amp 120 volt service and they always had deteriorating cloth over rubber insulation. I would often have my helper strip a couple of feet of old Romex to tie up extension cords and even then can not recall seeing either the outside jacket or the black or white insulation showing signs of overheating. Heard one of the reasons they switched from 60 degree C type NM Romex to the far superior 75 degree C type NM-B cable back in the early 1980's was due to the NM deteriorating in attics of homes in the south. Most old homes up north had very few wires in the attics. Most were just for bedroom & attic luminares. At one of my post I mentioned that while attending an IAEI continuing education class the brilliant guy from UL labs told us that UL collected old maybe hundreds if not over a thousand samples of Type AC ( BX ) & NM cables from all across the country and did extensive testing on them. Old clothes over rubber insulation in old AC cable failed think he said it was the Megger test along with some others. The thermoplastic ( always looked like TW insulation to me ) on type NM cables were in fair to good shape.Often came across burnt wires due to loose screw on cheap receptacles. Maybe only an inch or two of insulation was burnt. Came across a burnt ground wire the entire length of a 50' 10/4 cord that feed a portable welder. Somebody used a very long lug to connect the ground output from the generator that was firmly touching the welding case and the ground stinger had most of the fine wires broken off and a worn out stinger clamp that did not attach tight to anything causing most of the 150 Amps or so to be carried by the 30 amp #10 guage cord. Only time I came across a long cord that was smoking it's entire length.
I have attended numerous demonstrations and seminars by most major wire nut manufacturers (Ideal, 3M, Wago, etc) and they all say that if you install the wire nut properly, there is no need and no advantage to pre-twisting the wires. In fact, at least one of them indicated that pre-twisting actually has a negative effect on the quality of the connection. Pre-twisting is an old skool method that is no longer necessary.
For what it's worth my dad always taught me to have a good mechanical connection before wire nut or before soldering or before whatever always have a good mechanical connection first!!
You can listen to wire nut manufacturers all you want, and I don’t doubt that if done perfectly every time they would be fine, but the point is that NO connection that has been properly pretwisted and then capped with a wire nut is going to fail. They just won’t. Whereas plenty of connections that weren’t pretwisted and were only capped with a wire nut and then twisted have failed.
I would have liked to see how 12/2 wire would have faired. This would have been an excellent way to show viewers how circuit breakers work. Maybe the same test using a 15 or 20 Amp outlet. I've never seen an outlet on fire, thank GOD. This might be a wait-up-call for some people.
You've the exception then for wire nut effectiveness. Love WAGO utility but a pre twisted wire under a wire nut is gold standard for connectivity. And stranded wire never holds un pretwisted against solid wire. WAGOs are heavens gift for solid/stranded connections.
Great video, it's nice to know we can depend on our house wiring! Though most failures that cause fires happen at connections that are improperly made (untwisted wires inside wire nuts or loose screws at outlets). I'm installing Wago's now every time I have to do wiring around the house.
this test doesn't represent a residential application. the wire would burst into flames well before 60Amps at 120v. do not try to correlate this test to your homes wiring amp capacity. there is a reason 14/2 is limited to 15amps breakers. and 12/2 on 20amp breakers.
@@darkshadowsx5949 Obviously, but I'm just saying that failure points are at the connections, not the wiring inside walls, unless they are damaged somehow. A nail or a screw driven through a cable is never a good idea, but 💩 happens! Observing the code and minutea are your best friends.
I would like to see the same test using wagos. I think wego's would fail before a wire nut would. I don't think the wago holds the wire as tightly, therefore creating more resistance and heat.
I'd like to see it under 110vac with increasing current. As it stands, 70 amps at 1.47vac (that's what I think that I saw on the meter) is ≈ 103 watts. Under nominal conditions (110vac and 15 amps) it should be fine up to 1650 watts. So this isn't a proper test.
15 gauge? I have never heard of that for AC wiring! I had heard that knob an tube was thinner wire - I wonder if know and tube was 15 gauge. Many the woven insulation was more able to handle higher temperatures than soft plastics?
Voltage is irrelevant to ampacity. Regional high tension lines are limited to 500 amps due to wire size. To get more VA or wattage if your power is 1 they raise the voltage to many thousands. The limit then becomes the arc distance.
The setup he has is actually dissipating 103 watts. Very different than being able to carry safely enough electricity for an appliance to be able to dissipate 1650 watts.
That meter was only really measuring the drop across the romex cable, not what was trying to be supplied. Supplying this test wire with a 110v source would yield a roughly similar voltage drop as this ~10-50V source as it's a near dead short. Amps is amps, voltage is largely irrelevant in a short circuit type test such as this. Well, to a certain point where arcing and insulation breakdown comes into play.
Glad you like it - your not the only one who said that about measuring temperature. When I did it I just thought it would fun to see how much current #14 wire could handle beyond the rated 15A. Never expected the video to get this much attention. I have ordered a thermal prob so may some temp measurements in the future.
Apparently before wire nuts (and I think into the 50s) it was acceptable to twist the wires, solder, and then cover with tape. In a junction box of course. I have never seen it - I wonder if anyone here has, and if anyone has seen any failures on those types of connections.
Would like to see a repeat of this video, but with two wires of the same length. Then rough up one of the wires and fold it in half to see how rough handling the romex affects how much stress it can handle.
That is actually a very interesting idea. I will put it on my list of videos to do. Can do it right now - the weather is too cold to do outside and can do it inside with the toxic fumes. But next summer!
Fire is caused because of temperature, not current. So, you should repeat this test but with the cable inside a conduit, with the maximun amount of cables inside the conduit permited by regulations, and with those other cables at their maximum current permited by regulations. That way the temperature inside the conduit will be higher than in your test. The current to start a fire will be much, much lower. Edit: the conduit and the maximum amount of cables inside the conduit depends on where you install the conduit. There are regulations for conduits inside wood walls, brick walls, air, ceiling, soil, etc., because the heat transfer to the surroundings depends on the material of the surroundings. You should repeat your test following regulations. The current will be much, much, much lower.
NEC says you can't put wire with sheathing in conduit. Also a cable typically is a multi-wire strand which can't go in conduit. Just insulated wire. But I don't know where you are.
wire currant rating has nothing to do, directly, with heat. its all about the voltage drop due to resistance. though you are showing the said voltage drop, a 50 foot wire would be, well, about 50 time grater than your measuring... also agree with other comments about twisting wires before a wire nut. there is no code to do so. also if you have to take it apart for testing you will need to cut the twisted part off every time as the twisted parts are physically compromised.
The current (amperage) has everything do with heat. Without current no heat can occur. That's why when the Amperage was increased the wire began to heat up and even melt the insulation. Every electrician I've talked to (being an electrician myself) has agreed with the statement, "that when you think of amperage, think of heat. The more amperage you have the greater the heat." So the insulation on conductors isn't just about voltage, but it's rated for a certain amount of heat it can handle before malfunction. This video was somewhat based on that theory, but no temperature was given to help correlate the temperature to current. The other factor is based on load for sizing wire. And load is correlated to current. As an electrician when someone wants for an example a spa I need to know the Amperage to properly size the wire, because the voltage will always be the same, 120/240 coming from the sub-panel. And a to small wire would burn up under the load or amperage needed
@@TheForgottenMan270 Exactly, now tell this reviewer what every electrician worth their salt does to a wire prior to adding the wire nut and the wire nut package advises electricians to pre twist the wires prior to adding the wire nut. Wire nuts are not meant to creat a solid connection, they ware meant to protect the open wires like the insulation does.
Because at 120V (assuming you are in US or Canada or other 120V country) the current the heater draws is 1500 divide 120 = 12.5A whoch is way less than the currents needed to burn the wire. I can do it will less voltage because I am not supplying power to a heater or load at the end of the wire. All that matters in terms of the the wire heating is the current flowing.
The voltage tolerance on a 120 volt line in the US, according to the NEC, is 5% to the furthest outlet, or 114 volts. Most local power companies also allow 5% tolerance on the secondary side of their 7200/15400 lines, though the voltage is generally adjusted 2% over voltage to accommodate heavy evening loads when everyone gets home and starts loading the power grid simutaneously with H2O heaters, ovens, microwaves, and now, electric cars. I don't know why I find it hilarious that electric cars in many places are charged by coal powered facilities. Carry on sir 🙌
I guess that makes a Tesla a coal powered car :) People sure dont understand the greenness of electric vehicles is directly related to the power plants. Your point about voltage: With little current draw in my home, I have measured the AC from about 123V on low consumption times/days to as low as 115V on a day when air conditioners would be one. I'm sure if I repeated with my AC on it would be a volt or 2 lower. Almost exactly as you described.
@@ElectromagneticVideos Well, they don't give a Masters License to anyone man! 😜 That video was super cool, I've repaired cables that looked similar, but not a bad as that, and always wondered how spectacular the actual failure was. Thanks for the demonstration! I was also thinking about the fact that you used a welder, which produces pulsed direct current. Line voltage in a home is alternating current, and there are differences in how those two conduct through metals. DC tends to move electrons through the core of a wire, but AC tends to only move electrons on the surface of a conductor, and this phenomenon is called "Inductive skin effect." This is why stranded cables are used in industrial and commercial applications, they have much more surface area than a single round conductor. I'd like to see how many amps of AC power it takes to achieve the same result. I'm going to have to replicate your project at my shop someday, my curiosity has been more than stimulated 😃
@@CommunityGuidelinez Its actually such an old stick welder that the output is plain old AC! The skin depth for 60Hz in copper is about 8.5mm so for 1.6mm diameter #14 wire I would expect little difference between AC and DC anyway. But for larger industrial cables your absolutely right. I deal with a lot of RF stuff where in the Ghz region the skin depth is in the order of μm. For MHz RF sometimes Litz wire is used - essentially woven stranded so much like you described. By the way - great skin depth description! I hope you try the experiment. If you ever get to remove some 1970s Aluminum 12/2 would be really interesting to see how that holds up to overcurrent. It was used everywhere around here (Ontario, Canada) till houses started to burn down. Not sure how common it was elsewhere.
@@CommunityGuidelinez One more question for you: in RF metal pipe is often used since nothing flows in the center anyway. Is that ever done with high power AC power distribution? Or is stranded enough to mitigate skin depth for even the largest wires?
@@ElectromagneticVideos Thats an AC welder!? Wow I had no idea, that's really interesting, I knew they existed but it didnt cross my mind while watching. That's a great point about the skin depth of 60Hz AC in a small 14 gauge wire, there would likely not be a significant change. I'm in the US and go by the NEC/NFPA 75 code, and as far as our 2020 edition is concerned, stranded high power AC Conductors such as a 750 KCM can mitigate the skin effect. There is an adjustment factor for the conductors that can be determined by dividing AC resistance as listed Chapter 9, Table 9, by the DC resistance as listed in Chapter 9, Table 8. Funny thing is that these formulas were calculated on a specific size and type of cable that was determined in 1966 🤣 (Somewhere back near those tables is an informational note regarding that). Going a little bit outside of the box though, NFPA 780 covers traditional lightning protection system requirements, which I believe one could call "high power application." One of these requirements is that conductors intended to deliver electrical discharge from lightning strikes through a building or house should be a Class 1 copper type, hollow, braided wire. So in a way, yes there are similar applications in high power AC to running RF via metal pipe. Good stuff, thank you for responding with good conversation mate. 👍
run this at 120v as intended (or 600 if you read the rating) and see how many amps you get. 1500 watt heater runs at 11A-12A at 120V. i would almost guarantee if you use this for a dryer(30A) there would be a fire in a short time. am i not getting some point to amps here watts dont mean anything. all it is is volts x amps = watts. 50 watts is essentially a dim incandescent light bulb
Watts are important because you can measure heater output in watts. 50 watts for an incandescent bulb is not a lot, but three feet of cable inside your wall pumping out 50 watts of heat sure is.
The voltage here is along the wire - even at high currents - which is what produces the heat and is the same as what would happen in a real overloaded circuit. If the voltage between the wires was typical line voltage as you suggest (120 or 240V) the only difference would be when the insulation melts or chars to the point when the wires touch and short, we would have a massive over current similar what is shown at the end of the video. I would need a much more elaborate setup to do that safely so unfortunately I cant demo that right now.
Hi Grill Master, voltage and current are not independent. Think of voltage as the pressure that causes the current to flow. Apply a higher voltage (more pressure) and more current will flow. It's just like a water faucet where if you increase the water pressure you will have a higher flow rate of water.
@@wd8dsb and since in a real world scenario, house current is typically used at a higher flow rate; ergo, this experiment is invalidated and the results should be viewed as inaccurate... In relation to real world applications, that is.
Something else to consider is the temp that would cause breakdown of the insulation over time causing material failure (brittleness for example), rather than just reaching the deformation temperature.
This weird - I answered this a day or two ago, but it seems to be gone now. My apologies if this shows up as a duplicate ... Yes! And even just exposure to air seems to make the plastic insulation around the conductors get brittle over decades. Sometimes you see this in connection boxes. Add some warmth and I'm sure the process speeds up significantly. I remember from taking chemistry class as a student there was some sort of rule of thumb that for every 10C(?) rise, reactions in water tend to double in speed. I would bet there is some sort of similar dramatic increase in deterioration as the temperature rises. I wonder if there is a noticeable difference in cable that has been in warm attic for decades compared to the same cable in the same house in a nice cool basement or crawl space?
Very Interesting video.. Was an electrician for almost 20 years.. I have seen whole houses with washer/dryer, electric ranges etc running off two of those old arse glass screw in fuses with PENNYS behind them because they were blown. Wheat penny lasts forever. lol
I have heard about old home with only a few fuses - and pennies as fuses. Amazing that someone would install high power electric devices like ranges and dryers and not increase the the size of the fuse panel. Scary!
Would like to see this test at a constant 120vac reference. With the division of volts and amps you could run thousands of amps at a minute voltage. Show the limit in real world situations at 120v just nit picking, none the less interesting experiment 👍
Ohms law prohibits this unless you put a load in the circuit. Normally current is controlled by the load with a constant 120vac. In this demo there is no load (very small load of the wire) so the current is actually controlled by the voltage. The voltage drop of the wire is a factor of the wire's internal load. In a house the current is controlled by the load.
This was an interesting video of how to destroy a cable. Just a thought. You are giving the impression that it takes 50 to 60 amps before the conductor insulation is damaged. This is not correct! The insulation on the copper is rated at 90C or 194F. Once the copper goes over that temperature, the insulation starts deteriorating. So, over time being exposed to higher temperatures, the insulation will fail and a short circuit will happen. Also, a ampacity rating means it can be utilized at that amount of amps continuously and not damage the insulation. Not as you suggested. Most breakers however are not continuously rated at their size. They are rated at 80%.
I think you miss the point of the video. This is not "to destroy" the wire or he just crank it up to 100 to see it get destroy right away. This video showing the limit that wire can handle. And yes all the usage rating is set before reaching the deterioration limit.
Yes - I really just thought it would be interesting to very crudely see how big the safety margin was between the rated 15A and when it really melted and failed.
AWG 14 Rating for house application is 15amp. However, if you look in the CEC/NEC, there are application where you can do 20 and 25 amps. (For example, chassis mount, place where there is no Insulation). Wire nut, when the connection is properly made, have double the thickness of copper. So, they can carry more current than the wire. When they are hot, the connection is wrong. We sometime test them using a thermal camera.
I didnt know that CEC/NEC specifically allowed more than 15A on #14 in some circumstances. Thermal cameras - amazing technology. I got one and used in on later videos with 14-2 in insulation etc.
Since lightning is more frequent, question comes to mind, if one should have lighting rod system on roof like on farm steads ? Live in small city but have couple fir trees slightly taller than 'A' frame house but quite adjacent to them.
That is a really good question. I can only guess at the answer: its probably a cost benefit thing. The chance of lighting hitting any particular house is low and when it does, what is the typical cost of the damage? Many years ago I arrived at someones office that was located in a house minutes after lighting had hit. The EMP pulse took out the photocopier (they had unplugged it prior to the storm) and a a couple of computers were damaged (unplugged but on a wired network which acted like an antenna). Would a lighting rod have helped? The EMP would still take out a lot of electronics. It probably depends a lot on the home construction style in an area and the frequency of lighting. Insurance companies would insist on lighting rods in any area or situation (barn, tower of some kind) where they would produce a significant benefit.
Wire nuts are theoretically ideal, but in practice are error prone, especially for casual, careless, or hurried installers, or when combining dissimilar wires (such as 14-2 solid to a very flimsy stranded wire for a lighting fixture). And while wire nuts measure as the least resistive compared to push in and lever couplers, the amount of resistive load is not high enough to make a difference for safety or for efficiency, while lacking the clear see through body that allows for easy confirmation of proper wire insulation stripping distance and fully inserted and secured wire that prevents loose wires (shorts or disconnection) and the very real risk of fire starting arcing. The fact that the push in and lever couplers are faster (time is money) and easily reconfigurable more than make up for the minor increase in cost, a no brainer for anyone that isn't a technophobe or a stubborn "this is how I've always done it" luddite.
@@SuperChad1313 yes, with training and vigilance you can use wire nuts just fine, but it's not a perfect world and humans most definitely are not perfect, even professionals, so it remains that wire nuts are now an inferior out dated product where widely available affordable alternatives exist that are better suited to the purpose, with little redeeming qualities to wire nuts beyond industry inertia and reluctance to change.
From an engineer's standpoint it all makes perfect sense. But then I need a special wago for 2 wire connections, one for 3 wire connections, one for 4 wire connections. Wire nuts are more compact and versatile at a fraction of the cost. I keep a few wagos on the truck for certain situations, but I use them sparingly.
I strongly disagree with this demonstration. #14 AWG wire cannot handle 40 A at 120 or 240 Volts. #14 is rated for 15 A at 120/240 V, but only for 80% duty cycle (80% Duration ON with 20% duration OFF in 5 minute increments). All electrical will generate heat. For anything to work, there must be sufficient capability to dissipate the heat, or limit the current to prevent heat generation to the point of destruction. Even with lower voltage (12 to 80 V) driving a stepper motor which has 100% constant on, I will only use #14 AWG wire as 12 Ampere constant on.
I agree. His title was how many amps but no mention of Volts. So I’ll give him that. But 60 amps at 120v or higher that wire would be glowing. 60 amps at 2 volts is only 120 watts. Vs 7200 watts at 120v. What I don’t like is if some homeowner or handy person who doesn’t understand electrical principles might think they could run 14/2 for say their electric water heater or something with a high current and it will fry. I’d like to see this with a high voltage.
The voltage reading was the voltage drop across the wire with NO LOAD. This was a current control source, not a voltage control source. If you dead short any wire with 120V ac you will certainly get a MUCH MUCH higher than 40 amp current. Like maybe 400-4000 amps. That's why a dead short blows the breaker so fast and throws hot melted metal in your face if you accidentally touch wires in a box. Current control is not generally used so most people don't understand it. We are mostly used to voltage control. Point being, you will never get 40A at 120V across a dead short. You'd have to have a load to do that. If you put a load (like a light bulb) and it had just the right resistance to make 40 amps at 120V, then the result would be exactly the same as what this video shows. It's the amps the fry it, not the volts.
@@hastypete2 thank you for the the reply I think I may try this experiment. I understand yes. That wire would explode. I’d like to see if that is in fact the case in real world scenario. I can run 14 on a 50 amp breaker powering a heating element out of an air handler.
You missed the point.... 14 gauge is rated to SAFELY be used in a 15 amp circuit.... But you are wrong.... 14 gauge can handle 100 amp in some situations..... He was looking for the failure point in HIS situation.
NEC rates 14 awg NM 15 amp at 120 volts . That's a power rating. Test it at a millionth of a volt and you'll get a bunch of amps before it gets 🔥. It's all about the watts. Run your electric water heater on 120 volts and try to take a hot shower.
The wire is rated for 120V@15 amps. That is around 1800 watts. Your set up is wrong for measuring voltage. The welder at 15-20 amps should still be pushing 20-25 volts or in that ball park. Your grounding clamp should not be touching the ground. My vacuum cleaner pulling 15 amps can get a lot warmer than your set up at 30 amps. Instead of twisting the ends together you need to connect them to a dummy load. Shorting them out is not really a valid test to show how wiring reacts when electricity flows through it.
The cable is probably rated for 600V (this is the insulation rating), so it could theoretically carry 600V*15A = 9kW of power (that is not the same as how much power the cable itself will dissipate as heat). His test setup is fine; he is measuring the voltage drop across the cable which shows him how much power the cable itself is dissipating as heat due to its finite resistance. If the grounding clamp was not connected to ground, there would be no current flow. Where else would it be connected to? The cable can't tell the difference between your vacuum pulling 15A and his test setup pushing 15A through the cable. It all essentially "looks" the same to the cable (the voltage drop would be the same across the cable).
The welder may be designed to operate at those voltages and currents in normal operation, but with it's output shorted with a short length of wire like this it will fail. Ohms law says that the voltage will be the current in amperes multiplied by the resistance in ohms. No exceptions. Your vacuum cleaner gets warmer at 15 amps because the voltage is 300 times higher. Watts is voltage multiplied by current.
@@david672orford Neither the cable nor the vacuum are dissipating 1800 watts as heat. The wire is dissipating much less because its resistance is much lower. The video is demonstrating the amount of power that the cable itself dissipates. The vacuum might heat up, sure, but the majority of the power is being used to create the vacuum, not heat it. Since you're aware what Ohm's Law is, you would have to agree that the cable can't "see" the difference between the the test setup in this video and the vacuum example. With 15A flowing through the cable (in this test setup or the vacuum), the voltage drop across the cable is the same.
@@stuckbreaker8586 Yes, I agree with you completely. The test rig shown in this video produces correct results. Those who keep bringing up how many watts this cable could deliver to a load at 120 volts are confused about what is being measured in watts in this video. And yes, only part of the 1800 watts remains behind in the vacuum cleaner as heat, but it is easily far more than the 21.45 watts which this cable dissipates at 30 amps. So Bryan Rocker should not be surprised that the vacuum cleaner gets warmer.
In RC aircraft they push more than that, but they are fine stranded, very short and use high temp silicone insulation. It is a tradeoff between power loss as heat and weight.
Good point about that - there is always a tradeoff and your RC case is a perfect example of how different tradeoffs are appropriate for different applications.
According to the instructions for most wire nuts that I can find (actual information from the manufacturers) pre twisting is acceptable but not required for installation.
Just throwing this out there, I've been in construction for 15 years, and I've never seen an electrician pre-twist the conductors, before putting on a wire nut. I'm not an electrician, but I have quite a few friends that are, and that just doesn't happen on a typical commercial jobsite.
There was another comment (that I cant find now) from an electrician saying he was specifically taught not to twist them to make it easier to change later (I'm paraphrasing). My comment was maybe it is a regional/local preference one way or the other. I'm in Ontario, Canada and most houses I have lived in (except one) twisting seemed to be the way it was done. Course that's a very small sample set - way smaller than what you would have seen over 16 years in the business. So maybe not twisting is more common.
@@Nick-bh1fy That's an interesting comment. I actually did a stress test in another video where I massively overloaded a twisted and untwisted connection and the twisted one was in surprisingly good after 270 Amps. Untwisted not so good, which really supports what you said. Its here if you are interested: th-cam.com/video/Y-2LmKlQW2A/w-d-xo.html
@@ElectromagneticVideos the way I was taught was the marrette is only there to insulate the connection and not act as a physical bonding connection between multiple conductors. I strip wires slightly longer, twist from the end and cut off the copper that has been nicked and you’ll have a connection that won’t come apart.
@@Nick-bh1fy Sounds like a real quality way to do it. The wire spring thing in the standard marr type connector really seems quite flimsy, particularly with the softer plastic used today. The old black ones with much more rigid plastic probably could exert more force on the wires, but even then I'll bet your technique would produce a much better connection.
If you mean because I pre-twisted the the wire, pre-twisting or not is a manufacturer specific thing and it seem like half the electricians pre-twist and half dont.
@@supabiscuit I completely agree with you! But you wouldn't believe the (or maybe you would) the number of people who vehemently argue against it. Seems like electricians are divided 50-50 on the subject.
@@supabiscuit Heat sure is an indication of bad connection. I would guess that with thermal imaging cameras getting so common place nowadays many more bad connections are getting found before something bad happens these days than they use to.
Rated at 15 amps, which is about 20% less than what it can really handle. There are amp ratings PER HOUR for every wire we can use. I think appliances are rated for 1250 watts or about 1/2 of what the wire can really handle.
A good splice on wire is created by mechanically joining the wire, solid or stranded. The 'wire nut' is just there to replace the insulation if the wires are properly twisted together first. 3M Red/Yellows are my favorites, but I never rely on them to make the splice. Strip, pinch and twist, then cap the splice with a good wire nut.
@AgentOffice I've only been an electrician for 40 years. Splices that are twisted tight first then capped do not come apart. Just write nutted? Those are the fails that result in call backs to fix.
If you want to see MORE REALISTIC TESTS for various insulation types from fiberglass to foam in a 2x4 wall, look here th-cam.com/play/PLHUfJmsprIcTVwSgCkTJnkinJSWrZY7DY.html
Can you do another video use 12-2 and run it through a wire nut , a wago , & just twisted to see which melts first?
@@thewonderfulwonder1614 I will definitly do some version of that - numerous requests for wage tests. It may have toi wait till spring unless I can rig up a fume hood in my basement!
Can you do this with a wago connector?
@@fernandoalcantar7907 Yes - have had plenty of requests for extensive Wago testing. Will definitely do it. May have to wait till spring since I cant do it inside due to the fumes.
I’d like to see a test that would simulate two space heaters running at the same time on a circuit of 14 gauge wire and see how long it takes for the wire to start toasting. Initially the wire can probably hold up but after say 10 to 12 hours that’s when it may start to fail. Many homes slap a 20 amp breaker on the 14 gauge wire incorrectly. So this is a real world scenario.
Twisted solid core wire can get brittle overtime, as well that it can be difficult for someone to take apart safely. If you want your wiring to last, no matter what you do, please leave an ample service loop if possible. You or the next electrician will be very grateful!
Very goo point about making sure there is extra wire length for future (re)work - such an easy thing to do yet some people seem to skimp on it.
Agreed, but easier said than done when the box is small, the devices large, and many wires are in the box. And even if it is done, it will of course get shorter with each modification.
Speaking as an electrician doing residential service work for about 20 years, not once did I ever see evidence of failure due to a lack of pre-twisting. The failures that typically happened:
1. Using quick-connectors on the back of devices, especially when used for feed-through applications.
2. Using side screws on a device and a screw came loose or wasn't tight enough to begin with (especially for feed through...).
3. Trying to fit 4+ wires into a wire nut, and one of them wasn't gripped by the threads in the wire nut. 2 or 3 wires tends to grip very well, without twisting.
@@DonTruman yep
Pretwisting makes it a PITA for the next guy for sure. No reason to do this unless you’re trying to force 5-6 conductors into one wire nut, which I always avoid.
I'm not surprised the wire nut didn't heat up appreciably. It really isn't carrying any current. Since the connection is actually the twisted wires, the wire nut serves only as an insulator.
Yes! I'm sure minimal current goes through the thread spring in the nut compared to the wire to wire connection.
You are right. As long as the wire nut is working correctly it actually has the least resistance. Its gauge is that of #14 and #12.
The wire nut may not be carrying much current at all, but it's still screwed onto bare copper that's carrying 60+ Amps, so the impressive thing for me is that the wire itself was so cool. That's a testament to how efficient a conductor the twisted wire at the end was.
I'm sure if you removed the wire nut and measured the twisted wire itself, you'd see pretty much the same thing. Seems like those twists were doing a pretty good job all by themselves (at least in a controlled environment where they can't come loose!)
agree, the twisted wires effectively double the conductor thickness an the wire nut's metal adds to this too. most the current wouldn't carry through other than being more concentrated at the entry/exit points
the wire nut looked like it had metal threads inside so it is actually conductive in that spot
Applied destructive testing is one of the best way to learn. Thanks for releasing the magic smoke for us.
Funny - when I did this I never expected to get so many views. I did end up doing more realistic ones afterwards (14-2 in a 2x4 wall, 14-2 in a 2x4 wall embedded in insulation etc), but this video somehow is stuck in TH-cam's algorithm :).
Now if only somebody would put gasoline into a kerosene heater, to explore why that might not be a good idea? Lots of YT videos destroying things, but I have not seen that one yet.
Sounds like an outdoor test, not near anything to be concerned about.
@@yosefmacgruber1920 I think I'll let someone else do that one :)
@
Well if they have done that test, I sure have not found it.
But some channels seem to love destroying things. I recall some long time ago, some channel that likes to over-volt things until they can't take it anymore.
@ Well those videos get a lot of views. I occasionally do videos of this nature but limit them - I dont want this channel to be simply the burn things up channel.
Note the voltage drops at 8:22. That drop in voltage means the resistance decreased. In this setup, that can only mean that the wires are now touching before they get to the wirenut. In a voltage driven circuit (such as household power) at that point the current and power would have gone way up. Since I think we can assume that to get to that point the circuit protection has failed, at that point I would say the fire starts...
Good point about a real household circuit. One would sure hope currents never get to these levels. One commenter did point out how people upped fuse values in the old days if a fuse blew. So maybe back then sustained overcurrent may have been more common and there would have been the possibility of even the too large fuse saving the day when the wire shorted.
@@ElectromagneticVideos In the 50's, we replaced fuses with a few coins, screwing the bad fuse back in to hold them in. (After fixing the problem) Many people thought it was a permanent fix, but they caught on by the third or fourth rebuild. Other poor results are obvious by now, I hope.
Sorry dude... you need to test at 130volts 15 amps....
@@randytrant I was under the impression that current is the sole contributor it heating and voltage is irrelevant.
@@hhn2002 it is. 15 amps is 15 amps. Also current depends on how much voltage you apply. There is no way to limit current to 15 amps at 120v with just the wire resistance.
Would be good to have a thermal imager rather than relying on touching the live wire (that is rigged to fail). This was a great video though, none the less!
Your the second to suggest a thermal imager! I will have to look for one. Glad you enjoyed it!
Even a infrared thermometer would’ve been great to see actual temps!
@@dodgeguyz Based on suggestions like yours I did that in the "wire in fiberglass insulation" video I put up today: th-cam.com/video/Df7bAEdIILI/w-d-xo.html
Its not like touching that "live" wire is dangerous other than possible burns if its that ridiculously hot, but this is less than a volt for most of the test, so its doubtful that you would even feel a shock until the mid 20's or even 30v.
Yeah would love to see this under a fliar gun,
Keep in mind this experiment has the Romex in open air, which is reasonably good for letting heat escape, instead of passing through insulation in a wall cavity. Also he's only giving it several seconds to heat up. Don't use "didn't catch fire after 10 seconds in free air" to decide what wire gauge you will use inside walls!
If the jacketed wires are warm on the outside of the jacket, they're hotter inside the jacket, and hotter still inside the wire insulation. And most of us hope our house wiring will last for decades.
6:50 watch the voltmeter climb: the resistance of copper wire increases with temperature. It's getting hotter.
Great comment and let me add to that. Any experiment - mine or someone else's, should not be taken as any encouragement or suggestion to use anything other than the approved wire for a certain application. Its just interesting to see very roughly what the safety margin might be.
It was just academic. Obviously you should follow electrical codes.
@@shaunnightfire8269 My thought exactly!
I’m just a homeowner handyman, but I think you would have entirely different results if you used a length of 100 feet. A short 5 foot length is not meaningful and leads to incorrect assumptions
@@dustmaker1000He mentioned resistance around 6:30. 100’ sounds a bit long for household wiring unless you have a very big house. I’m trying to remember the longest run of my old house and I don’t think it was too much more than 50’. Perhaps 60’. 🤷🏻♀️
I once ran a 1500 watt space heater on a 100 ft 12 gauge extension cord that was wrapped around one of those plastic circular cord wrap things- so the cord was insulating itself from cooling off.
I was just going to run it for 20 minutes so I thought it would be OK.
I ended up falling asleep and when I awoke suddenly 5 hours or so later and ran out to the garage the whole garage smelled like hot plastic and the cord insulation was noticeably soft.
It permanently changed the insulation on the outside of the extension cord
Wow - what a real and scary example of the damage that can occur from current overheating the plastic insulation. Interesting that the insulation was permanently changed. I what what chemical change was caused by the heat on the plastic.
@@ElectromagneticVideos I'll try to get a picture of it and send it to your email in the next few days.
Still kind of spooks me a little bit.
I had an InstantPot that had some kind thermal event too. It turned off before there was any damage to the counter but the IP was shot and wouldn't turn on
@@jeffa847 That would be interesting to see.
I wonder if the instapot had some sort of internal thermal fusible link that saved the day after whatever failed.
That's the length of the cord being the problem, this is basic electrical knowledge
@@Cheetahpuma-g2e 1500 watts on a 100 foot 12 gauge cord is OK according to all the charts I have ever seen. Some might call that basic electrical knowledge too.
I have done it plenty of times even though I don't really like to and have felt a little warmth around the plugs when run for a long time but I never had problem with the rest of the cord getting hot - thus my original post pointing out that wound up it's a lot worse on the cord.
Try this with wire nuts and wego connectors and see which holds up best
You must have read my mind. I posted a video on that this morning! Here is the link th-cam.com/video/cMVnOZCGljc/w-d-xo.html . Enjoy!
Oh nice. By zee way... where in the world did you come up with the idea of attaching a stinger to Romex, and various other things found within the confines of an electrician's van? This is quite a cool idea to play with.
@@DarthTwilight OK - I have to tell you the story! A year ago, I was at the local Habitat for Humanity ReStore and there was a vintage welder that had been marked down to $100 because it was not selling. I guess it not being DC was a deal breaker for most people. At $100 I couldn't resist and figured if I ever needed to weld something thicker than my MIG could handle it would be good to have. I also had at the back of my mind that it might be useful if I ever needed to do some high current tests. To put things in perspective, I'm an EE and always liked doing experiments of all kinds. It sat in my garage, and a year later (3 weeks ago) I was cleaning out some old extensions cords which I have always never trusted and thought - might be fun to see how bad they are before I throw them out. So I did (the video is there) and actually was impressed by the newer ones. That made me think - since I'm setup to do it, lets see what 14/2 can handle. Nothing very profound - just my idle curiosity and posted the video on my obscure little channel. I had no idea that it would get so much interest! Great thing is, many comments have been so thought provoking it had been way more fun that if I had just done the test and not posted it. The videos I have posted since then are all suggestions based on the 14/2 one.
Already been done by people who know how to spell Wago.
@@waytospergtherebro Ok Grammer Nazi. I guess when you work for someone else, aka to earn a paycheck, you need to worry about spelling. Thanks for pointing that out. I'll remember next time that I need to worry about it.
The temperature rating of that 14AWG NMB cable is 90°C. The amp rating is good to 25A. The NEC prohibits its use over 15A. Nice demonstration.
Thanks for the info!
Yes. The NEC has safety factor upon safety factor built-in. It’s apparent all across the code. Things can be stretched much past their code “limits” before catastrophe occurs.
@@alex43223 Very true! Although I was surprised how the safety factor becomes in some later experiments I did with 14/2 inside insulation as you might get in an outside wall.
So the wire hits 90C at 25A, but is that buried in insulation, or hanging in free air? And NEC actually prohibits its use above 80% of 15A, or 12A continuous.
@@stargazer7644 The NEC allows wire to be used at 100% of it's rating continuously, it's the OCPD that's limited to 3 hours of 100% rating, anything longer than that it has to be derated to 80%. Any load that could potentially be on more than 3 hours at a time is considered to be continuous. So you are correct in that the entire circuit is limited to 80% of the OCPD rating, but the wire itself is not the limiting factor. Also, you cannot use the 90C table unless every device the wire is landed on is also rated for 90 C, and nearly all circuit breakers are limited to 75C. In the absence of a temp rating on terminations or connections, you have to default to the 60C ampacity table for the cable. Which in this case for 14/2 is 15 amperes. Mike Holt has some excellent videos where it's explained in more detail.
A few years ago I was doing some welding, and absent-mindedly attached my grounding clamp to my bandsaw, and the return current found it's way through the 120 volt shop wiring. It lasted about 20 seconds at 75 amps before it let loose. Lots of charred insulation.
Oops! So you did my test before I did! That must have been a real pain to fix!
@@ElectromagneticVideos I was lucky- most of the current path was 12 gauge, and it survived fine. There was only one section of 14ga. that I had to replace
You will Be suppressed how often this happens in workshops. Especially with the older non inverter welders. The return path ends up going down the earth ( ground wire for you guys). This cable gets so hot it melts the insulation on everything. The new inverter welders tend to run earth free on the outputs and is less of a problem, ( I think this is the case but never actually tested it). If your work is touching the building steelwork make sure you have a good return connection
@@johnwarwick4105 I didnt know it was a common thing. Surprising that someone didnt make a current sense relay module for the welder ground/earth wire that would disconnect power the instant that happened. Could have have prevented what I'm sure were costly accidents.
I'll bet your right about the inverter ones (or at least some of them) having. I have done a fair amount of switching power supply design, and many have no electrical connection between primary and secondary. There might be a regulatory requirement for a ground connection perhaps for some perceived safety issue or RF suppression although I'll bet many on online sites might not exactly be built to adhere to any standards!
Be glad the 14awg was there. It may have acted as a fusible link protecting the 12awg
As a 66 year old Master Electrician I appreciated your test. It helps to see the tolerances of the material we use in the field so we have a better foundation to talk to our customers. We all go through the classes and books but to actually see the breakdown of the conductor is impressive. This gives me more confidence in the load carrying capacity of house wiring especially with today's insulations which raise or lower the load capacity. Thanks ;)
I glad you found it useful. I did a few other videos with 14/2 in 2x4 walls with various types of insulation such as fiberglass and foam. I am actually a bit concerned about situations like a fully loaded cable between piles of insulation in hot attic in the summer running an air conditioner. I would probably ask to have the wire increase in size by a gauge or so in situations like that.
I'm an electrical engineer so I don't get to see the real-world examples of things the way you do (and also usually deal with low power RF signals most of the time). Have you ever seen NMD or other cable damaged by running close to the max rated currents when situated in the middle of insulation in an already hot environment? Any sense from your experience how close to the edge of the safety margin we are with modern cable and insulation?
@@ElectromagneticVideos Well in the field we follow the NEC which requires no more than 80% load on any circuit and manufacturer recommendation for dedicated circuits for apparatus like dishwashers, A/C's etc. so for the most part we do not see break downs like your test unless the work is done by unlicensed people like Home owners who simply wire to make things work not considering potential consequences. However with the advent of more home generation equipment and EVA's and other new apparatus, I can see more overloads and fires with misapplication and improper wiring of such equipment. I will say I see a lot of interruptions and breakdowns using these Mexican made receptacles, switches and foreign made new light fixtures which do not have the same oversight in manufacturing that used to be the standard in US made parts. Especially after NAFTA which made foreign made material the standard in the construction industry iMHO
What I would love to see is more test videos on Service Equipment in todays environment using ARC FAULT devices. I see these products not proven in todays world. But time will tell. Thanks again.
@@carylamari6546 I actually also have seen scary stuff done by homeowners. I have a buddy who does home renovations on the side and you wouldn't believe what was in one of his projects - the previous owner (and I am embarrassed to have to say was an engineer!) used everything from speaker wire to coax to hook up additional light fixtures and outlets. We spent a fair amount of time searching through things just to find the hidden things to point the electrician to to remove or replace. I wish I had been making video back then. What an example of what not to do! The plumbing was equally "interesting".
Interesting you mention home generation and things like EVs. I will be adding some (used) solar panels to my house and have been researching the often not too to well publicized specs of the breaker panels when attached to loads + generation sources at the same time as the grid. I can sure see how things can go wrong if the panel bus rating is less than the sum of power sources if large loads are attached in spite of everything having properly rated breakers.
And yeah - general cheapening and lower quality parts does not help!
@@carylamari6546 Well I just came across some Cutler-Hammer Arc Fault receptacles on sale, so I will be trying to see what sorts of arcs can trip them. Still have to figure out how to do it - probably with everything running though either a gfci or isolation transformer (I have kw sized one) and making the arc using a switch with poor snap action or some sort of touching cables current limited buy a light bulb ... . So Arc Fault stuff to come in the future!
I worked in cable, when foreign voltage melted our lines, it was always at the splice points of the tap or the ground block. We could cut the melted part off and the cable would still be fine. You need to test a longer length circuit with multiple splice types for an accurate test.
Torque screwdrivers! Use em!
That was interesting AND educational! Well done! Never thought to test house wiring before, but I feel a lot better about the wiring in my house now.
Glad you liked it but things are not as good as in this video when in a real wall - did some later videos where I built a section of 2x4 wall with insulation around the wire. The safety margin goes down quite a bit as expected.
@@ElectromagneticVideos I would completely expect that. I'm a communications engineer, and essentially what you are suggesting relates to heat dissipation, due to the resistance of the wire, it develops into heat, and as long as that heat can be dissipated, the wire is fine, same deal with a forced air electric heater. If the fan quits, that wire is going to burn up unless it is protected with a heat sensor to shut it down of course. If you don't have a thermal camera, they are great investments, as you can find heat and cold leaks in your house, and they are awesome for troubleshooting circuit boards and defective components.
@@jimturpin I actually did get a thermal camera for the later tests - great toy to have! Communications Engineer? What do you do - I used to be involved in HF/VHF/UHF comms. Now I'm more in the faint signals detection type of stuff in the microwave bands. HF was great fun - nothing cooler than transmitting vast distances with a few 100w.
Good video! As you started reviewing the wire nut I realized that most copper beyond the initial contacting twist also forms a heatsink for the bit of copper at that first mating twist, thereby helping to keep it from being the point of heat failure. Very nice little safety bonus I had never thought of before.
Thanks! Yes - as old and simple as the wire nut is, it is a remarkably effective device. I have tested other connectors in later videos - some are remarkably effective and arguably easier to use or disconnect, but nonce connects better than a properly used wire nut.
Growing up I remember just sticking in ends to see if it fits whatever it was I was trying to use and if it fit it was the right one. With that said, I’m very impressed I’ve never set a fire but I definitely gave my kids a live performance like you did here, showing how a cord will catch fire if it’s not meant for the device or the devices board will fry ruining it.
Always great to expose kids to science experiments if done with the appropriate safety precautions. Most kids naturally love finding how things work - at least until some of the textbooks used in school drive any intensest in the subject away.
NM cable conductor insulation is rated at 90C - 194F. The wire nut is rated at a minimum of 105C = 221F. NM amp in regards to the NEC is 15A
Interesting that NEC requires the wire nuts are rated at a higher temperature than the cable. I wonder if its because of an assumption that they might be a poor connection and more heat generated?
@@ElectromagneticVideos UL's connector standards try to assume worst case scenarios, there are some different categories too like usage in explosive atmospheres, Used to be that wire nuts didn't have a current rating at all and it was tied to ire size ampacity. But the basic connector standard now says 20 amps.
A lot of problems arose when there was a major push for WAGO connectors and adopting IEC standards, but the whole IEC standards are a joke! IEC does no testing and doesn't require any. 98% of IEC "certifications" are "self certified" by the manufacturer. Basically this means that the manufacturer attests to their device meeting the engineering standards. They use a statistical based "verification" process, meaning they don't question anything unless there are a very high percentage of complaints. In extremely rare circumstance, they may request 3rd party testing. Manufacturers are not even required to test or keep testing records, I've worked in industry for man years and IEC certified stuff is junk!
WAGOs tyoically say 32 amps on them and also has a UL certification. But the UL rating is 20 amps, 32 amps is the IEC rating! The Japanese rating on these is only 20 amps also. And strangely enough, Japan's residential voltage is 100 volts! WAGOs have been used all over Europe but they use 230-240 volts as the standard residential voltage. So on average, the typical currents for the same appliances, lighting, etc. operate at half the current of the same stuff in North America. So the odds of a statically significant number of failures is low and complaints are minimal. But all you need to do is take apart a WAGO to know it's not a good connection!
Part of the problem today is that most installers think certifications are equal. But the truth is that these standards ae apples tp oranges comparisons!
The inherent resistance of WAGO connectors is multiple times that of wire nuts. But because the dissipated heating is "I squared R" , twice the current is 4 times the heat dissipated. For the residential wiring installer, they just know that WAGOs are easy to use. Most of these installers have little formal electrical theory training and very few states require any kind of certification. I refuse to call these installers, electricians! They know how to connect things up and mist know the code, but few really understand the theory, Kinda like the cable installer guy who has no idea how the modem works! I find it interesting that WAGO markets to contractors but not engineers in the US. As an electrical engineer I would never approve or specify these connectors, I think these are probably OK for low current applications like LED lighting fixtures, but I would never use these in typical residential wiring.
'
Free air as well
just an FYI
the adoption of twisting wires before putting on the connector came from the use of Marr connectors which had a small screw in the side which held the two wires together. if you didn't twist the wires then they became flattened as you tighten the screw and there is a lot of chance the cross-section area of The wire would become very reduced and over a period of time of heating and cooling the Matt connector would loosen off.
Ken
The voltage suddenly dropped to nearly half at the point that the insulation began melting even as the copper heated and began increasing its resistance. Then it began rising again from the lower value.
I suspect a short part way along the cable, which reduced the impact further down the line (eg: at the far connector).
I was gonna try to do this, but I didn't know how to do it safely. Should've known that someone else would have already done this. Thank you!
Your welcome! I did more realistic tests with the 14-2 in 2x4 wall surrounded by various types of insulation. Not as exciting but a bit of an eye-opener as to how the safety margin drops drastically with insulation. Here is the link if you interested: th-cam.com/play/PLHUfJmsprIcTVwSgCkTJnkinJSWrZY7DY.html
When I bought my home 10 years ago most of the house was wired with 10ga cloth and vinyl wrapped wiring, with some scattered modern 12/3 for new outlets added, and they added 10/3 to dedicated outlets to each window air conditioner outlet.
The worst overload was the living room which had four lamps, each with a 100w bulb and run off a single run of 12/2 w/o any ground, which also included the front porch lights and two outside outlets and four single bulb fixtures in the basement below, each with 100w bulbs.
It showed no sign of any failures but I did run new 12/3 runs to each outlet, one to the porch and two to the basement lights on that side when I tossed the old screw in fuses for a new breaker panel. The old wiring was plastic insulated wires in some sort of silver cloth wrap.
A few bulbs in the basement still have that wiring but little by little I'm replacing those fixtures with LED units, and for now, every bulb in the house is LED.
I lived in a few houses with messes like that. An some that included silver cloth platic wireing that I think came just before NMD. Sounds like your a bit like me - every home I lived in was safer when I moved out than when I moved in.
that doesn't seem overloaded. 12/2 can handle 1900w without issue and upto 2400W for non continuous loads, if it was overloaded it would continuously flip the breaker
I think you do not understand electrical math? The chance you had 400 watts of lighting and then plugging in a 1500 watt vacuum is unlikely to trip the breaker.
Great demonstration. Thank you. The wire can really take quite a bit of amperage before it failed.
Honestly this is a terrible test. it gives people the false sense of safety on residential wiring.
no one should put 60 amps at 120v AC through a 14/2 wire. he had it at 2v before the coating started to melt.
your house doesn't run on 2v AC..
I'm not sure what this says about me, but if you keep blowing things up, I'll keep watching. Thanks for the vid!
I do blow up occasionally, but also do variety of those things so hopefully some more of my videos will be of interest!
This was interesting to see, and one should keep in mind this is in open-air. If you had a fan blowing on it, it would go higher, and if you put building insulation around it, it would heat up much faster and support less current. Finally, the fact it burned at the corner is also a clue, the thinner the wire is at a particular location, such as a bend or pinch-point, the greater the resistance there, and the more heat generated. So, to compensate for all of those factors and more, it is rated for 15A max to ensure safety.
Very good point. I actually did follow up experiments with the 14/2 in a fake 2x4 wall filled with various types of insulation and the results are exactly as you predict.
Tgis video is very interesting and educational. It also shows why you should never just upsize a circuit breaker. I enjoyed the video
Glad you liked it! Thats the perfect takeaway from the video! What has surprised me is that apparently some people do upsize breakers - a really dangerous thing to do! I did some later videos with wire inside walls filled with insulation - it doesn't survive nearly so well in that more realistic situation.
would like to see you get a hold of some old knob n tube wire and run this test.
I did! th-cam.com/video/Yk9P2pKIza0/w-d-xo.html
@@ElectromagneticVideos awesome. thanks! glad to see all the old wiring I've removed from my homes didn't look like that.
@@routtookc8064 Ha! Yes, probably a good thing!
Do it again with home insulation around the wire.
Many people put their wiring buried in home insulation.
Good demonstration.
Pretty Cool.. I'll never doubt wiring up a motor again with the yellows!
Yes! They are amazing good at higher currents!
My old 1956 house used 15 gauge wire with black woven insulation. Would be interesting to see how much that would take until flames. A few of the breakers were 20 amps and it hadn't burned down.
@Kelly Harbeson 14 gauge wire is far from rarely used. It's the standard wire for residential homes. At least around here. 12 wire is for 20 amp circuits where required, like bathrooms and kitchens. When someone at work tells me to start pulling wires, I reach for the 14/2 unless told otherwise.
There are plenty of limited current circuits in commercial work, and wether you're using THHN in FMC or MC in commercial, or Romex for residential, 14 gauge wire is 14 gauge wire. However, you're right, you really hardly ever use 14 in commercial.
How many blown 15 & 20A fuses were replaced with 30A?
@@fredmauck6934 100% this. My parents house has what appears to be a 500A main panel because they are all 30-40A fuses. Even with the oversized fuses the air conditioner will trip the fuse if the microwave is already on.
@Kelly Harbeson I don't know where you live, but here where I live everything but the kitchen is 14 gauge. The kitchen obviously needs more capacity so it gets 12 gauge. Some people don't like handing 12 gauge( harder to bend and also to manipulate in the boxes.
Great demonstration and demonstrates a (very) good reason to use fuses or circuit breakers...
Thanks! Yes - and probably a good example of what happened when put a penny under a on old screw in fuse in the old days ...
I recently left a wheelchair manufacturing outfit and part of my job was testing the electronics modules. The motors on ours were fed with No. 10 stranded wire, and if you stall the chair against a block and firewall the joystick, they would pull over 200A for a short time, which amounts to approx 100A per wire to the motors. No ill damage occurs.
The key is "for a short time". Not long enough to heat up enough. I assume the system has some sort of current limiting in the electronics in case of an extended stall?
The way you touch the wire is spine tingling, good luck
It not as scary as it looks! Because the end is shorted there are only a few volts needed across the conductors to push those levels of current though and generate the restive heating effects. I wouldn't be touching them if it was live 120V!
Would there be much difference if you had say 50ft of wire instead of 3 ft? In actual applications, you wouldn't have that short of a wire.
The dissipated watts per foot along the wire would be the same for a given current, so for the same current the same rise in temperature would occur over the length of the wire. There is a corresponding per foot voltage drop (which in these tests is the voltage I put across the wire). So at the end of 50ft you would get a resulting lowering of the voltage presented to the load. At rated current on a typical branch circuit, I believe the code says no more than 3% drop is allowed. So for this type of overload on a long wire you might get perhaps a 10% drop lowering the 120V the load sees to 110V or less. If the load is resistive that would drop the current by roughly the same percentage. But if it is a constant power load like a electronic power supply or induction motor, the load will draw roughly that much percent more current making the situation even worse. Of course in a real situation the wire also goes though 2 by 4s, insulation etc probably making it hot at somewhat lower currents.
What if I did it in a vacuum at -50degrees with a three phase capacitor……….
@@dirkdiggler2052 I think you would need a flux capacitor for that :) Actually you bring up a great point - it is really hard to keep electronics cool in a vacuum. Infrared radiation and conduction of heat to other parts of the structure is the only way to get rid of heat. I know the Soviets actually used sealed boxes with gas inside holding their electronics to help with cooling. I wish I had a vacuum chamber to try 14/2 in a vacuum and see how low a current would melt it.
Well everyone knows that the white should have been connected to the return and the feed to the black. It burned because it had reverse rotation. 😂
@@intheharness :)
Super video! I see a few suggested a thermal imager! Also would be cool (actually hot) to see actual degrees temperature along with your observations as to touching and explains the heat! Again, enjoyed the video!
Glad you enjoyed it. I'm getting more and more tempted to get a thermal imager. I do have a thermocouple temperature probe on order. Now that I think of it, I wonder if my IR temperature gun would work or if the wire is too narrow for it.
@@ElectromagneticVideos It would be worth checking and seeing if your IR temp gun will pick it up.
@@unclemarksdiyauto I will!
This is a short term acute test. High temps over time will break down insulation, which is a major problem, especially when the wire is within insulation or otherwise contained in an unventilated space.
Yes! I have also seen the insulation on cable that is 30/40/50? years old get brittle, particularity where outer plastic has been removed. Seen similar aging effect on plastic in vintage appliances. I wonder if modern plastics have improved and are less prone to that?
Great demo. I like your narration through the increasing amperage. Make sure to remind folks to not try this at home.
Thanks for sharing.
Thanks - glad you liked it! Yeah - maybe I need something at the beginning of each video saying "don't try this at home". Do a have warning at the end ....
@@ElectromagneticVideos yes, I saw the warning at the end. I noticed you stated the 14 ga wire was only supposed to carry 12 amps in a home situation. You did a great job. Thanks again.
@@thomasglessner6067 I really appreciate that Thomas! You know what was a disconcerting surprise to me - in some of the videos that came after this one I built a 2x4 wall section and did similar things with the 14/2 inside between insulation. The safety margin drops so much in that situation that if I was building a new house today, I would make sure 12/2 was used at least everywhere it goes though insulated outer walls or (worse) hot insulated attics.
Yes you can melt plastic with high heat. The problem is the gradual deterioration of 14 gauge wire with 20 amps over many years of use.
Yes - thats a huge problem with plastics over time. I have come across old 14-2 where the plastic is brittle and shatters where it enters a junction box. Unclear if modern plastics are better.
I'm curious what the resistance is for the length of wire you used and if you tried a 30', 40', and 50' length of wire if there would be any difference in the results.
Exactly. That would make a marked difference!
Well for a given current which in a normal situation is determined by whatever the load is, the heat emitted per foot of cable does not change if the cable is made longer or shorter. Your right the resistance goes up for a longer cable, but the result heat is distributed over the longer length and the temperature rise remains unchanged. What does make a difference is if the cable in a wall filled with insulation and as expected things do go bad at a lower current. I did do a FAQ video here if your interested in more details: th-cam.com/video/CP3-jcpzZeI/w-d-xo.html
At 2vac 60amps the wire is only pulling 114watts, the wire is rated at 1,710watts 120vac at 15amps. Try this experiment again but with a load that doesn't short out the voltage :) still a very educational video!
120vac at 60amps would be 6, 840 watts, oh wow.
It doesn't make any difference. At 60 amps this cable will always drop two volts and dissipate 114 watts. If you jack the voltage up to 120 and connect four electric heaters to draw 60 amps, the cable gets two volts and the heaters will get 118 volts and dissipate 7080 watts.
I'm a retired Engineering Technician, which means I built prototypes in the R&D dept. This was back in the day of wire wrap prototyping. I got curious one day and connected a length of AWG 28 wire (Kynar wire wrap wire.) to a Kepco 20V 50A power supply to see how much it would take to "fuse" it (melt it). It started to glow at around 23A and finally melted at 27 amps. Not too bad for such a tiny wire. Wire can handle quite a bit more than one would think, it's the wrapping material that usually gives out before the wire will. If you were to repeat this test to try to "fuse" a single wire, I doubt your welder could do it TBH.
I remember wire wrap prototyping! Also have a vintage Motorola TV from the early 70s where wires between circuit boards were wire wrapped. That TV was remarkably prone to intermittent connections at the wire wrap point - I'm guess int was due to a poor manufacturing process since wire-wrap had a reputation for making good connections as far as I know. (Am I wrong?)
It is remarkable how much current a wire can handle beyond what what its rated for.: 20+ amps for #28 sure sounds remarkable.
As far as fusing single wires - the antique welder is more powerful than you thinks. In more recent tests were we tested some connectors (Wagos and others), when we exposed #14 bare wire to over 200A, the wire melted and broke before the connector did in some cases (!). But - it take 5 to ten seconds to do it. So you prediction would have been correct with slightly thicker wire.
@@ElectromagneticVideos In my experience with wire wrap, there was never any issue with reliability (we had systems in service for >10 years). This was due to the fact that the wire was usually wrapped around a square post around 5 turns. So each turn had 4 corner contact points. The only issue was potential shorts if you bent the post as they were like a half inch long. We used it for both analog and digital prototyping. What was great about it was easy rework if the design needed changing, which it often did in early development. As far as wire testing, "fusing" is not really a valid test, other than to see how far you can push it. It serves no real world application. A 150A service main breaker would trip long before it would melt a 12 AWG wire, depending on whether it was a magnetic breaker or thermal. That's one thing I doubt many DIYers know about, the different types of breakers. That's kinda getting in the weeds.
@@markh.7650 So you have confirmed the the reputation that I thought wire wrap had - good quality connections. I did a little wire wrapping in the 70s and never has any issues - but that was all for short term hobby stuff when I was a kid/teenager. I wonder how Motorola messed up when they wire wrapped those TVs. My guess is maybe after wiring many TVs, the powered wire wrap guns wore in some way and became less effective. Or the posts they uses didnt have sharp enough edges. Probably didnt matter much since that was not too long before Japanese imports essentially ended TV production in Canada and the US.
I had a space heater at work under my desk and during the day while I was there the fan failed and the heater caught on fire. I unplugged it and threw it out. What would have happened if I had been away from my desk?
Thats a scary scenario. These days they are supposed to have thermal cutout fuses or fusible links to prevent a fire in situations like that, but clearly one cant those protective devices to always work.
@ElectromagneticVideos yep. This was back in 2004 and it was a plastic walmart heater. Small one.
@@ryanyoder7573 And I'm sure there are still plenty of those heaters around and in use. I wonder how many fail in as dangerous a way as yours did.
With household wiring, shouldn’t it be 120 volts?
Voltage has little to do with testing the ampacity of a conductor
This video reminds me of some scary pages on the subject of Federal Pacific Electric breaker panels. Despite several design revisions, independent tests have demonstrated that the circuit breakers in these panels are prone to failing to trip.
Yes - I have read about them too. Its hard to imagine how much worse it could be with those breakers. While the simple heating and melting of the plastic wire insulation would be similar if someone plugged in too big/many loads like heaters, once a short did occur in the cable as a result of the plastic melting the AC power system would not be inherently current limited to a few hundred amps like the welder is. You could easily expect 1000s of amps flowing and the copper wire vaporizing. Hopefully the main panel breaker would trip fast enough to prevent a more catastrophic result - no idea if the main breakers have the same failing to trip problems....
i still replace those zinsco breakers with aftermarket ones- people dont want to spend for new panel- although i tell them the dangers
Beware of Frank Adams as well
It would be interesting to run a strip of this wire between some insulation and apply the current to see when it gets too hot.
I am actually hoping to have time to try something like that this weekend. I'm planning to use two 2x4s to make a simulated 16" OC section of stud wall with fiberglass insulation. Will also be interesting to see what happens to the wire in the holes in the 2x4s.
@@ElectromagneticVideos please make a video with different types of conduit (plastic and metal) to see how much heat is dissipated. I think with a metal conduit inside a brick wall you can easily overcurrent 2 times without issues.
I'm so glad you made this video. I just had an argument with some moron and he was freaking out because someone else put a 20 amp breaker on 14/2 ... i was like Dude you're safe. for safety concerns they often quadruple and quintuple rate the wires for worst case scenarios. let the breakers do their job. they don't cut the ratings so close for safety reasons.
You know - even if it were just for insurance reasons the breaker should be switched. And some breaker have quite a large margin of error for when they trip. But take a look at some of the followup videos to this one - particularly the ones with 14/2 though insulation. With a well insulated wall there really is no room for comfort. So much so that if I were having a house built today, I would get 12/2 for the 15A circuits - I was not expecting that.
@@ElectromagneticVideos well that’s the code. 14/2 for lights and 12/2 for outlets. Because outlets typically have more shit plugged into them. Not a lot of people overload lights
@@chuckholmes2075 Interestingly I don't think 12/2 is required for outlets yet here (in Ontario) but I could be wrong. Certainly good to hear its in the code elsewhere.
@@ElectromagneticVideos in the NATION WIDE book it is.
@@chuckholmes2075 That's great to hear!!
In military comm school, you have to build a radio set using no solder, just mechanical connections between components - twisting the leads together 3 full turns seems to work well
Wow - building a radio like that must have been a great experience. I'm guessing it was more than a simple crystal set - so amplified crystal radio? regenerative radio? I'm guessing superhet would have too many connections to build like that?
I think testing it at the mains voltages(120v/220v)should give more realistic observation as the cable will be stressed both at high voltage and high amperage imitating the actual household scenario
Voltage doesn't matter
@@kylekirby6424 maybe you're right
@@AgentOffice Doesnt matter? Be caution! Its about the devices wattage. if u have for example an audio amp that will deliver a continu 600w of power, under a supply battery of 12v, that wire will explode at 50A.. u cant exceed max 10A.. its all about the delivered watt and your pressure, this wire can handle a device of max 100w
Thank you for noticing that! I felt like I was the only one lol I was thinking the same thing from the start of this video..
@@AgentOffice yes, the fuck it does… voltage makes a big difference plug 120 V lights into 240 V circuit. and you tell me what happens! But I will insist for you not to because of how destructive and potentially dangerous it could be!
A good idea would be to use an infrared thermometer.
Sweet video. Intentional electrical fires in the garage has been a pastime of mine since it was my parents complaining about the smell. Would be interesting to see how different environments effects this, such as bundled conductors, passing through studs, different conduit types, or buried in insulation. I’ll have to do some tests of my own.
Go for it! I'm going to try 14/2 though fiberglass insulation between studs and also covered in spray foam which should really hold in the heat and make cable insulation melt at lower currents. Conduit would be really interesting. I dont really trust the PVC conduit - if you try it please let me know!
@@ElectromagneticVideos i dont trust the pvc conduit either, keep the videos going!
The connection point to a cheap receptacle .
Makes a super hot spot. That high current kettle in the kitchen. Is a prime place for a fire.
@@assassinlexx1993 And if the kettle itself is old with blades on the plug being tarnished, put that in your cheap receptacle and the combination is even worse!
@@ElectromagneticVideos electrical tea kettles ?
You had a great tight twist in that wirenut. I wonder what it would look like if the wires were not twisted at all?
I really should do some testing of that sort of thing in a video. I'm sure it would create some heated discussions - there seems to be a huge divide between electricians with some adamantly advocating pre-twisitng wires and others being against it.
Excellent video, and I am totally amused by the 'experts' who keep commenting you have it all wrong... you need 120 Volts. The wire is 'rated' for 1,800 W, (120 V x 15 A). They conveniently leave out the 'R' parameter of Ohms Law. The only thing that matters is I and R to determine P (the heat energy over the length of the wire). Nobody cares about _supply_ voltage. The topic of the video is _voltage drop_ across the wire, hence the low voltage, which results in high current, due to low resistance and therefore significant heat (Watts). The formula for this test is *_I² x R = P_*
Yes - I reply to the people who nicely express they confusion about that and try to explain, but totally ignore the "your an idiot" type comments. You can have a discussion with those types.
You certainly explain it very nicely.
The legitimate complaint some have mentioned is the cable is in open air. A number of followup videos are with the cable in a 2x4 wall section with different types of insulation. The safety margin sure goes down!
Good test but time also plays an very important role. I tried the same thing with a 0,75 square mm (typical lamp wire size) wire and it could do 100A for about 10 seconds. Impressive but 10A for an hour or two will also melt it.
The real test would be to use a 15 Amp CB, and see if you can cook the wire without tripping the breaker
@SomeDumUsrName he wasn't talking about 14g wire, from what I can tell. He said 0.75 square mm wire, which I'll assume is the common way wire size would be measured outside america. (I'm used to awg so idk)
Very bad example I would not call it a test. Use the formula not the amp probe. The resistance is for all practical purpose is 0 If you look on a breaker 15 Amps or 20 Amps they will read 10,000 Amps RSM 120 volts/0=( dead short) And also with # 14 which is rated at 15 amps. You are not suppose to have but 80% continuous . The capacity of a conductor is based on the insulation.
I was hoping this experiment would tell me what amps were dangerous with household systems. However it’s not obvious whether what matters is amps or watts. I’m guessing it’s amps in the wires rather than watts in the whole circuit. My mcb s are 15amp. The plugs and sockets and wiring are rated 10 amps. With a double socket it would be possible to have 20 amps going round with a kettle and toaster and maybe something else.
i did a similar test with new wire to K&T wiring, and it actually failed in order from new to old, though the K&T never failed. it took 90 A never failing (it did get very hot, and oozed rubber out of the cloth)
K&T generally is so far apart that it is considered 1 wire suspended in air, and can dissipate more heat into the surrounding air than the two wires adjacent to each other inside the sheath shown here. It's all about if the wire can dissipate enough heat to avoid burning the insulation.
@@glenndoiron9317 yes, that's why it can be used at somewhat higher currents for a smaller wire size.
90A! Wow. Its held by ceramic insulators, right - they didnt crack when it got hot? I had heard it was great as long as it didnt get messed up by modern upgrades.
@@ElectromagneticVideos didn't crack or anything, and it didn't even get that hot, i could put my hand on the wire, the 1940's "Romex" style wire held up very well too, until the outer insulation cooked til' it became conductive carbon and started glowing. Yes, it is fantastic so long as it is not covered by insulation and doesn't get over loaded by dangerous modern additions, usually by homeowners that do not know what they're doing. i have actually wired one of my storage shed's with it, and used an 1800's fuse board that i built myself. works fantastic. I'll one day do a video on it
@@gtb81. Incredible that did vintage setup like that! I hope you video it - I just subscribed to your channel so I dont miss it. Just watched the vintage lightbulb video!
14 is rated at 20 amps in the table , derated to 15 for safety and again to 12 continuous.
at this rate why not derate it for 0 amps. thats 100% safety.
@@nicksgarage8295Right 😒 thinking the same thing over here
Thanks for this video. I now understand why our local code limits voltage drop on cables to 3%. In extra long cable the heating effect would be even greater and so the current capacity even less.
Yes - the longer the cable, the more total heat generated for given current and with a proportionally grater voltage drop. It is worth pointing out the heat generated per foot depends on the current (and resistance per foot of the wire) so the extra heat generated is distributed of the longer length and the temperature rise is the same regardless of length.
That's a good point. The code is based somewhat on voltage drop, not just heat in the conductors. A large voltage drop can burn out motors.
Not at all. If voltage drops, current drops too. To long wires would make the installation simply not usable. The breaker will trip if the current exceeds 15 amps. The wire is designed to handle 15 amps safely and should not melt even when it is 1 mile long, but how your 120 v bulb or heater can work if there are 20 volts coming into it?
Would the results change if it was 50 amps at 120v ?
It would not change. The heating per foot is from the current running though the wires, not the voltage between them. So only the value of the current matters.
Now if it was hooked up to a real 120V circuit with a load at the other end, one difference would be that there would be a circuit breaker in the circuit, and the moment the plastic insulation melted to the point that the wires in the cable shorted, the breaker would trip and cut the power. So it would be less dramatic than in this test where the current keeps flowing after the cable shorts internally.
Seems to me that the wire nut never saw more than 70 amps, if that. A short circuit apparently occurred in the first third of the wire as the insulation melted.
rsA couple of things.
I'm not sure the wire nut had the full 60 amps at all. it looked to me as though the wire had melted and shorted at some point, diverting the current away from the wire nut. Nevertheless, it did hold up pretty well which is good news.
The real 'safe' current carrying capacity depends on more than the wire itself, but also in all the situations in which it might be installed, according to regs etc. Even a much lower current will cause a failure if the wire isn't able to dissipate the energy at a temperature below the plastic melting point. That's why extension leads should always be completely uncoiled, regardless of the length actually needed for a given application. I've seen whole rolls of extension cables drums fuse into a solid mass of plastic - even when used well within the rated capacity of the wires.
I worry that people watching your videos might come to an unsafe conclusion, thinking that a 15 amp wire (which as you say is only rated for 12 amps continuous), might actually handle 20 or so amps - way below the 60 amps you demonstrated to be a problem.
I once witnessed a house fire in a house near me. All put put fairly quickly once the dire department showed up. On investigating the cause, it turned out they had trapped a thin brown two wire extension cord under the leg of a desk. Even though the load was way under the limit for the wire, being trapped in a tight space, the wire slowly got hotter and hotter until the wood of the desk leg itself ignited. If the wire had shorted, it would have presumably tripped a breaker and not started a fire.
Interesting video, but of you can, please make it clear that no-one should run wires anywhare near their maximum continuous current ratings. Even if the wire nuts hold up.
Cheers
"I've seen whole rolls of extension cables drums fuse into a solid mass of plastic - even when used well within the rated capacity of the wires." I'll bet may extension cords are in use spooked up like that. Can sure see how the heat can build up dangerously.
Your point about warning people is well taken. I do say it in the description - would hope people read it.
60amp on 2v.. but if u have a supply of 12v and having a current draw of 60amp, that cable will explode in a instant.. its all about watts.. people should do the math..
The thing I don't like about 14 is that about the time you want to give it one more twist, it breaks off.
No
At 7:48 - started to burn at the sharper bend. How long would it last at 20A? 5 minutes?
I would guess almost indefinitely unless sandwiched between thick thermal insulation. There is a significant margin of safety as there should be. Many circuit breakers can be quite inaccurate as to what current it takes to trip them and after how long. I have seen specs for some that allow a 2x overcurrent for up to half an hour before tripping. So the #14 should be able to survive a 2x overload (2x15A=30A) for half an hour without failing and it seems to be able to. Of course that should not be taken to means its OK to use #14 for 30A!
Wow, that demonstration really lets you appreciate the codes and the wiring that we have in place in the United States. Barring any malfunction of a breaker, any short circuit in the system will immediately be terminated and I guess the biggest danger in the house that’s wired to code is WHAT THE HUMANS WHO LIVE THERE DO TO CREATE A PROBLEM😳
Thank you for this demonstration. Wonderful. Makes me feel good about the home I live in.
Its great to see how large the margin of safety is! But is not always as good as in this video. Take a look here at a later video I did th-cam.com/video/lFdSXTKsKwA/w-d-xo.html - one of a number where the wire was in between insulation in a wall. As expected, melts at lower currents and I would actually use a larger than code required wire in places like a hot attic if I was having a new house built - or even anywhere where the wire is embedded in insulation. . .
Testing to failure is aerospace-level stuff. Thanks!
Its always interesting to see when things fail!
Always good to remember that the capacity of the wire is a factor of length.
A short wire is a lot more robust than the same wire at 250'
In the real world yes, a longer wire increases the voltage drop which then further increases the current. For this test its irrelevent. Resistance and heat dissapation should increase equally as wire length increases.
@@otov100 could you please explaine how?
Can you please explaine ?
@@insylem one would think that for uniform wire what matters for failure/melting is wattage dissipated per unit length. Since resistance grows linearly with length, voltage drop and total wattage grows linearly with length, and wattage per unit length remain constant
@@otov100 in the real world the shorter wire isn't more robust though. A 250ft wire will fail at the same current as a 2ft wire. That larger voltage drop is spread over a longer distance so the heating per ft stays the same.
But you do end up with much less usable voltage at the end
Best most reliable connection is to strip wires about 7/8" then pretwist using long linesmen pliers, trim ends of wire even, install wire nut, twist with linesmen pliers until at least one full turn of insulation , Tape with a few wraps if quality tape.
You know, its been ages since I have seen tape around the bottom of a wire nut!
@@ElectromagneticVideos Started out in a large slaughterhouse that between all the vibrating crushers, vibrating screens, high speed centrifuges and nightly high pressure wash down had to tape every wire nut. Opened up junction boxes that had 4" of water and energized 240 volt submerged well taped wire nuts that still worked. If not taped would have grounded out. Also always taped every device ( switches & receptacles ). Can never remember ever having a wire come loose on a screw that had a few wraps if quality electrical tape. Pays to go the extra mile.
@@JohnThomas-lq5qp That must have been interesting. I am amazed that wire nuts did so well in such a wet environment even with careful taping like that. Equally impressive surviving longer term vibration. I once had to vibration certify an embedded device - it was staggering how quite mild vibration will eat through insulation or anything else that was rubbing over a few days. You certainly convinced me that taping a wire nut is the thing to do. By the way - the best thing about this video for me has been comments like yours. So interesting to hear things like that!
I'm not an electrician but that was a very good demonstration thanks..
Your welcome! However, please be aware that this is a somewhat unrealistic - the cable in normally confined in walls with much less air flow, and often surrounded by insulation. Under those real circumstances, it fails with considerably lower currents. Here a link to those tests: th-cam.com/play/PLHUfJmsprIcTVwSgCkTJnkinJSWrZY7DY.html
Like the weakest link in a chain, it's the compromised inch of copper wire or bad connection that starts the fire. Great test, thank you.
That a really good point - a bend, scratch, tarnished area, loose connection ......
That is a fun video to watch.
However, I would caution viewers of this video from assuming that Romex/NM-B wiring has "lots of built in margin" and can safely be pushed beyond its rated ampacity limits. My understanding of the electrical code is that it is acceptable and allowed to bury NM-B wiring under insulation, inside walls and attic spaces. Therefore, it is not uncommon for the wire to experience much higher thermal resistance (compared to being exposed to free air), and consequently much higher temperature rise, for a given current level. For example, fully encasing an NM-B wire inside "R13" rated insulation should theoretically increase the thermal resistance and temperature rise by a factor of approximately 13, compared to having the wire free standing in air.
Since thermal power dissipation per unit length (and therefore temperature rise) is proportional to current squared (ex: P = I^2 * R), encasing the NM-B wire in R13 insulation is probably going to result in a somewhat similar temperature rise to running the wire at 3.6x of the rated current, but in a free air environment. In other words, for 14/2 Romex/NM-B wire, which is normally rated for 15 Amps maximum, when fully encased in R13 insulation, may experience about as much temperature rise as it did in this video, when he was pushing the wire to approximately 50-60 Amps (since 15 * 3.6 = 54A) in free air.
It should also be noted that most electrical related fires probably originate from the electrical connections at the ends of the wires. Thermal cycling from repeated heating/cooling often causes loosening of the screw terminals and other interconnecting devices over time. This is due to the thermal expansion coefficient of the metals, causing them to grow and shrink dimensionally as they heat and cool. The subsequent loosening of the interconnection causes increases in resistance of the connections, which then brings even more heating and more severe subsequent thermal cycling degradation. Additionally, bare copper and brass love to oxidize freely in air, which causes a buildup of oxide layer on the surface of the interfaces, leading to more resistance (and therefore much higher heating) over time.
Ideally, manufacturers of wire interconnects would get their act together and start making better quality connectors, which have high safety margin, redundancy of contacts and retention mechanisms, along with active strong spring retention force, rather than single fixed screw/bolt terminal connections, which often loosen over time due to thermal cycling.
What a fabulous summary of all the concerns and considerations! Thanks for taking the time to write it. Your point regarding the effects of insulation: Assuming I have time, I am planning to do a similar informal test of 14/2 in an insulated wall section tomorrow. It may be a less dramatic video but will be interesting to see what happens.
I don't buy how hot type NM-B cable can get inside a R13 insulation. When they switched from NM cable in early 1980's the type TW insulation was only good for 60 degrees C. Type MN-B has type THWN insulation and rated for 75 degrees C . Have removed thousands of feet of mostly older type NM cable from homes & businesses and never came across signs of overheating on cable jacket and the individual conductor insulation. Now that the NEC requires all screws & bolts used to secure wires must be done with a torque driver or torque wrench greatly improving reliability. At an IAEI continuing class the instructor told us that UL went around the country and rounded up hundreds if not thousands of existing device and took them back to test facility to check for proper torquing. Think less then 35% had the proper torque , 20 % excessive torque and remainder too low torque. Told us that over torquing is just as bad as not enough torque. Out of they over 100 attendees that night less then 10% sorry to say owned a torque driver. Before retiring I worked at a rich fortune 500 company who refused to purchase torque drivers, IR camera & circuit tracers.
@@JohnThomas-lq5qp That survey of devices where only 1/3 were correctly torqued is telling. Would be interesting to know how many of them had signs of problems as a result. When you started, I'm guessing torque to a spec was not a thing, other than perhaps really hi powered stuff. I wonder when it started becoming common if not required.
@@JohnThomas-lq5qp you never came across overheated jackets on old NM wiring? Really. I find this fascinating because I have seen it quite a bit. I've even seen it in my old home (built early 1970s) and had to replace it. All the NM was in attic and experienced very high heat for decades plus current draw from kitchen appliances.
@@theelite1x721987 I started out doing residential work first few years then after 15 years seldom did any residential work due to fortunate enough to get tons of commercial work. Myself and another 10th grade industrial shop Vo Tech student rewired a 3 story row house by our selves. Took 250 man hours to rip up floor boards, chisel out paths in plaster over brick walls, etc. Did a lot of machine shops, tool & die shops and injection molding plants but would do work in owners, friends & relative homes. Even was lucky enough to do some electrical work in a 300 year old Quaker meeting house, newspaper, hospital and some 200 year old homes. I upgraded at least 30 or 40 old row houses that only had a 30 amp 120 volt service and they always had deteriorating cloth over rubber insulation. I would often have my helper strip a couple of feet of old Romex to tie up extension cords and even then can not recall seeing either the outside jacket or the black or white insulation showing signs of overheating. Heard one of the reasons they switched from 60 degree C type NM Romex to the far superior 75 degree C type NM-B cable back in the early 1980's was due to the NM deteriorating in attics of homes in the south. Most old homes up north had very few wires in the attics. Most were just for bedroom & attic luminares. At one of my post I mentioned that while attending an IAEI continuing education class the brilliant guy from UL labs told us that UL collected old maybe hundreds if not over a thousand samples of Type AC ( BX ) & NM cables from all across the country and did extensive testing on them. Old clothes over rubber insulation in old AC cable failed think he said it was the Megger test along with some others. The thermoplastic ( always looked like TW insulation to me ) on type NM cables were in fair to good shape.Often came across burnt wires due to loose screw on cheap receptacles. Maybe only an inch or two of insulation was burnt. Came across a burnt ground wire the entire length of a 50' 10/4 cord that feed a portable welder. Somebody used a very long lug to connect the ground output from the generator that was firmly touching the welding case and the ground stinger had most of the fine wires broken off and a worn out stinger clamp that did not attach tight to anything causing most of the 150 Amps or so to be carried by the 30 amp #10 guage cord. Only time I came across a long cord that was smoking it's entire length.
I have attended numerous demonstrations and seminars by most major wire nut manufacturers (Ideal, 3M, Wago, etc) and they all say that if you install the wire nut properly, there is no need and no advantage to pre-twisting the wires. In fact, at least one of them indicated that pre-twisting actually has a negative effect on the quality of the connection. Pre-twisting is an old skool method that is no longer necessary.
For what it's worth my dad always taught me to have a good mechanical connection before wire nut or before soldering or before whatever always have a good mechanical connection first!!
Mechanical connection prior to the wire nut is in the nec code book
You can listen to wire nut manufacturers all you want, and I don’t doubt that if done perfectly every time they would be fine, but the point is that NO connection that has been properly pretwisted and then capped with a wire nut is going to fail. They just won’t. Whereas plenty of connections that weren’t pretwisted and were only capped with a wire nut and then twisted have failed.
I would have liked to see how 12/2 wire would have faired. This would have been an excellent way to show viewers how circuit breakers work. Maybe the same test using a 15 or 20 Amp outlet. I've never seen an outlet on fire, thank GOD. This might be a wait-up-call for some people.
You know, might be neat to do a test focusing on the outlet - maybe even #10 wire and see what it takes to burn an outlet.
Receptacle, not outlet
If you read the instructions for installing a wire nut, it specifically says do not twist the wires together beforehand
It actually depends on the manufacturer - some say that, other dont.
In my experience with wire nuts, the twisting of wires is automatic when you twist the wire nut onto the wires, and it bites into the conductors
A number of people have reported similar things. I think in the end not all wire nuts are made the same ....
You've the exception then for wire nut effectiveness. Love WAGO utility but a pre twisted wire under a wire nut is gold standard for connectivity. And stranded wire never holds un pretwisted against solid wire. WAGOs are heavens gift for solid/stranded connections.
Great video, it's nice to know we can depend on our house wiring! Though most failures that cause fires happen at connections that are improperly made (untwisted wires inside wire nuts or loose screws at outlets). I'm installing Wago's now every time I have to do wiring around the house.
this test doesn't represent a residential application. the wire would burst into flames well before 60Amps at 120v.
do not try to correlate this test to your homes wiring amp capacity.
there is a reason 14/2 is limited to 15amps breakers. and 12/2 on 20amp breakers.
@@darkshadowsx5949 Obviously, but I'm just saying that failure points are at the connections, not the wiring inside walls, unless they are damaged somehow. A nail or a screw driven through a cable is never a good idea, but 💩 happens! Observing the code and minutea are your best friends.
I would like to see the same test using wagos. I think wego's would fail before a wire nut would. I don't think the wago holds the wire as tightly, therefore creating more resistance and heat.
I'd like to see it under 110vac with increasing current. As it stands, 70 amps at 1.47vac (that's what I think that I saw on the meter) is ≈ 103 watts. Under nominal conditions (110vac and 15 amps) it should be fine up to 1650 watts. So this isn't a proper test.
15 gauge? I have never heard of that for AC wiring! I had heard that knob an tube was thinner wire - I wonder if know and tube was 15 gauge. Many the woven insulation was more able to handle higher temperatures than soft plastics?
Voltage is irrelevant to ampacity. Regional high tension lines are limited to 500 amps due to wire size. To get more VA or wattage if your power is 1 they raise the voltage to many thousands. The limit then becomes the arc distance.
The setup he has is actually dissipating 103 watts. Very different than being able to carry safely enough electricity for an appliance to be able to dissipate 1650 watts.
That meter was only really measuring the drop across the romex cable, not what was trying to be supplied. Supplying this test wire with a 110v source would yield a roughly similar voltage drop as this ~10-50V source as it's a near dead short. Amps is amps, voltage is largely irrelevant in a short circuit type test such as this. Well, to a certain point where arcing and insulation breakdown comes into play.
That 1650 watts goes to the device it's powering not the wire. A wire will fail at the same current regardless of voltage.
Very good experiment. One thing I wished you would have done is actually measure the temperature of the wire while you are cranking up the current.
Glad you like it - your not the only one who said that about measuring temperature. When I did it I just thought it would fun to see how much current #14 wire could handle beyond the rated 15A. Never expected the video to get this much attention. I have ordered a thermal prob so may some temp measurements in the future.
I wonder if soldering would provide a better connection than the prehistoric wire nut
Apparently before wire nuts (and I think into the 50s) it was acceptable to twist the wires, solder, and then cover with tape. In a junction box of course. I have never seen it - I wonder if anyone here has, and if anyone has seen any failures on those types of connections.
Would like to see a repeat of this video, but with two wires of the same length. Then rough up one of the wires and fold it in half to see how rough handling the romex affects how much stress it can handle.
That is actually a very interesting idea. I will put it on my list of videos to do. Can do it right now - the weather is too cold to do outside and can do it inside with the toxic fumes. But next summer!
Fire is caused because of temperature, not current. So, you should repeat this test but with the cable inside a conduit, with the maximun amount of cables inside the conduit permited by regulations, and with those other cables at their maximum current permited by regulations. That way the temperature inside the conduit will be higher than in your test. The current to start a fire will be much, much lower.
Edit: the conduit and the maximum amount of cables inside the conduit depends on where you install the conduit. There are regulations for conduits inside wood walls, brick walls, air, ceiling, soil, etc., because the heat transfer to the surroundings depends on the material of the surroundings. You should repeat your test following regulations. The current will be much, much, much lower.
NEC says you can't put wire with sheathing in conduit. Also a cable typically is a multi-wire strand which can't go in conduit. Just insulated wire. But I don't know where you are.
wire currant rating has nothing to do, directly, with heat. its all about the voltage drop due to resistance. though you are showing the said voltage drop, a 50 foot wire would be, well, about 50 time grater than your measuring...
also agree with other comments about twisting wires before a wire nut. there is no code to do so. also if you have to take it apart for testing you will need to cut the twisted part off every time as the twisted parts are physically compromised.
The current (amperage) has everything do with heat. Without current no heat can occur. That's why when the Amperage was increased the wire began to heat up and even melt the insulation. Every electrician I've talked to (being an electrician myself) has agreed with the statement, "that when you think of amperage, think of heat. The more amperage you have the greater the heat." So the insulation on conductors isn't just about voltage, but it's rated for a certain amount of heat it can handle before malfunction. This video was somewhat based on that theory, but no temperature was given to help correlate the temperature to current.
The other factor is based on load for sizing wire. And load is correlated to current. As an electrician when someone wants for an example a spa I need to know the Amperage to properly size the wire, because the voltage will always be the same, 120/240 coming from the sub-panel. And a to small wire would burn up under the load or amperage needed
@@TheForgottenMan270 Exactly, now tell this reviewer what every electrician worth their salt does to a wire prior to adding the wire nut and the wire nut package advises electricians to pre twist the wires prior to adding the wire nut.
Wire nuts are not meant to creat a solid connection, they ware meant to protect the open wires like the insulation does.
I wonder what would have happened to a Wago connector instead of the wire nut.
I actually did a wago test last summer. Here it is! th-cam.com/video/UT_hR0vwM8A/w-d-xo.html
So how do people get buy using space heaters that are rated at 1500 Watts and use 1.5 KW hrs?
Because at 120V (assuming you are in US or Canada or other 120V country) the current the heater draws is 1500 divide 120 = 12.5A whoch is way less than the currents needed to burn the wire. I can do it will less voltage because I am not supplying power to a heater or load at the end of the wire. All that matters in terms of the the wire heating is the current flowing.
The voltage tolerance on a 120 volt line in the US, according to the NEC, is 5% to the furthest outlet, or 114 volts. Most local power companies also allow 5% tolerance on the secondary side of their 7200/15400 lines, though the voltage is generally adjusted 2% over voltage to accommodate heavy evening loads when everyone gets home and starts loading the power grid simutaneously with H2O heaters, ovens, microwaves, and now, electric cars. I don't know why I find it hilarious that electric cars in many places are charged by coal powered facilities. Carry on sir 🙌
I guess that makes a Tesla a coal powered car :) People sure dont understand the greenness of electric vehicles is directly related to the power plants. Your point about voltage: With little current draw in my home, I have measured the AC from about 123V on low consumption times/days to as low as 115V on a day when air conditioners would be one. I'm sure if I repeated with my AC on it would be a volt or 2 lower. Almost exactly as you described.
@@ElectromagneticVideos Well, they don't give a Masters License to anyone man! 😜 That video was super cool, I've repaired cables that looked similar, but not a bad as that, and always wondered how spectacular the actual failure was.
Thanks for the demonstration!
I was also thinking about the fact that you used a welder, which produces pulsed direct current. Line voltage in a home is alternating current, and there are differences in how those two conduct through metals. DC tends to move electrons through the core of a wire, but AC tends to only move electrons on the surface of a conductor, and this phenomenon is called "Inductive skin effect." This is why stranded cables are used in industrial and commercial applications, they have much more surface area than a single round conductor. I'd like to see how many amps of AC power it takes to achieve the same result. I'm going to have to replicate your project at my shop someday, my curiosity has been more than stimulated 😃
@@CommunityGuidelinez Its actually such an old stick welder that the output is plain old AC! The skin depth for 60Hz in copper is about 8.5mm so for 1.6mm diameter #14 wire I would expect little difference between AC and DC anyway. But for larger industrial cables your absolutely right. I deal with a lot of RF stuff where in the Ghz region the skin depth is in the order of μm. For MHz RF sometimes Litz wire is used - essentially woven stranded so much like you described. By the way - great skin depth description! I hope you try the experiment. If you ever get to remove some 1970s Aluminum 12/2 would be really interesting to see how that holds up to overcurrent. It was used everywhere around here (Ontario, Canada) till houses started to burn down. Not sure how common it was elsewhere.
@@CommunityGuidelinez One more question for you: in RF metal pipe is often used since nothing flows in the center anyway. Is that ever done with high power AC power distribution? Or is stranded enough to mitigate skin depth for even the largest wires?
@@ElectromagneticVideos Thats an AC welder!? Wow I had no idea, that's really interesting, I knew they existed but it didnt cross my mind while watching. That's a great point about the skin depth of 60Hz AC in a small 14 gauge wire, there would likely not be a significant change. I'm in the US and go by the NEC/NFPA 75 code, and as far as our 2020 edition is concerned, stranded high power AC Conductors such as a 750 KCM can mitigate the skin effect. There is an adjustment factor for the conductors that can be determined by dividing AC resistance as listed Chapter 9, Table 9, by the DC resistance as listed in Chapter 9, Table 8. Funny thing is that these formulas were calculated on a specific size and type of cable that was determined in 1966 🤣 (Somewhere back near those tables is an informational note regarding that). Going a little bit outside of the box though, NFPA 780 covers traditional lightning protection system requirements, which I believe one could call "high power application." One of these requirements is that conductors intended to deliver electrical discharge from lightning strikes through a building or house should be a Class 1 copper type, hollow, braided wire. So in a way, yes there are similar applications in high power AC to running RF via metal pipe. Good stuff, thank you for responding with good conversation mate. 👍
run this at 120v as intended (or 600 if you read the rating) and see how many amps you get. 1500 watt heater runs at 11A-12A at 120V. i would almost guarantee if you use this for a dryer(30A) there would be a fire in a short time. am i not getting some point to amps here watts dont mean anything. all it is is volts x amps = watts. 50 watts is essentially a dim incandescent light bulb
Watts are important because you can measure heater output in watts. 50 watts for an incandescent bulb is not a lot, but three feet of cable inside your wall pumping out 50 watts of heat sure is.
It would be interesting to see if it did the same thing at lower current with more volts
The voltage here is along the wire - even at high currents - which is what produces the heat and is the same as what would happen in a real overloaded circuit. If the voltage between the wires was typical line voltage as you suggest (120 or 240V) the only difference would be when the insulation melts or chars to the point when the wires touch and short, we would have a massive over current similar what is shown at the end of the video. I would need a much more elaborate setup to do that safely so unfortunately I cant demo that right now.
Hi Grill Master, voltage and current are not independent. Think of voltage as the pressure that causes the current to flow. Apply a higher voltage (more pressure) and more current will flow. It's just like a water faucet where if you increase the water pressure you will have a higher flow rate of water.
@@wd8dsb Wonderfully clear explanation!
@@wd8dsb and since in a real world scenario, house current is typically used at a higher flow rate; ergo, this experiment is invalidated and the results should be viewed as inaccurate... In relation to real world applications, that is.
Something else to consider is the temp that would cause breakdown of the insulation over time causing material failure (brittleness for example), rather than just reaching the deformation temperature.
This weird - I answered this a day or two ago, but it seems to be gone now. My apologies if this shows up as a duplicate ...
Yes! And even just exposure to air seems to make the plastic insulation around the conductors get brittle over decades. Sometimes you see this in connection boxes. Add some warmth and I'm sure the process speeds up significantly. I remember from taking chemistry class as a student there was some sort of rule of thumb that for every 10C(?) rise, reactions in water tend to double in speed. I would bet there is some sort of similar dramatic increase in deterioration as the temperature rises.
I wonder if there is a noticeable difference in cable that has been in warm attic for decades compared to the same cable in the same house in a nice cool basement or crawl space?
Very Interesting video..
Was an electrician for almost 20 years.. I have seen whole houses with washer/dryer, electric ranges etc running off two of those old arse glass screw in fuses with PENNYS behind them because they were blown.
Wheat penny lasts forever. lol
I have heard about old home with only a few fuses - and pennies as fuses. Amazing that someone would install high power electric devices like ranges and dryers and not increase the the size of the fuse panel. Scary!
Would like to see this test at a constant 120vac reference. With the division of volts and amps you could run thousands of amps at a minute voltage. Show the limit in real world situations at 120v just nit picking, none the less interesting experiment 👍
Ohms law prohibits this unless you put a load in the circuit. Normally current is controlled by the load with a constant 120vac. In this demo there is no load (very small load of the wire) so the current is actually controlled by the voltage. The voltage drop of the wire is a factor of the wire's internal load. In a house the current is controlled by the load.
This is why I ran 12/2 instead of 14/2 on the 15 amp breakers. Rather trip a breaker than burn down the house.
Completely agree - If I was building a new house I'd sure do the same!
This was an interesting video of how to destroy a cable.
Just a thought. You are giving the impression that it takes 50 to 60 amps before the conductor insulation is damaged. This is not correct! The insulation on the copper is rated at 90C or 194F. Once the copper goes over that temperature, the insulation starts deteriorating. So, over time being exposed to higher temperatures, the insulation will fail and a short circuit will happen. Also, a ampacity rating means it can be utilized at that amount of amps continuously and not damage the insulation. Not as you suggested. Most breakers however are not continuously rated at their size. They are rated at 80%.
I think you miss the point of the video. This is not "to destroy" the wire or he just crank it up to 100 to see it get destroy right away.
This video showing the limit that wire can handle.
And yes all the usage rating is set before reaching the deterioration limit.
Yes - I really just thought it would be interesting to very crudely see how big the safety margin was between the rated 15A and when it really melted and failed.
AWG 14 Rating for house application is 15amp. However, if you look in the CEC/NEC, there are application where you can do 20 and 25 amps. (For example, chassis mount, place where there is no Insulation).
Wire nut, when the connection is properly made, have double the thickness of copper. So, they can carry more current than the wire. When they are hot, the connection is wrong. We sometime test them using a thermal camera.
I didnt know that CEC/NEC specifically allowed more than 15A on #14 in some circumstances.
Thermal cameras - amazing technology. I got one and used in on later videos with 14-2 in insulation etc.
Since lightning is more frequent, question comes to mind, if one should have lighting rod system on roof like on farm steads ? Live in small city but have couple fir trees slightly taller than 'A' frame house but quite adjacent to them.
That is a really good question. I can only guess at the answer: its probably a cost benefit thing. The chance of lighting hitting any particular house is low and when it does, what is the typical cost of the damage? Many years ago I arrived at someones office that was located in a house minutes after lighting had hit. The EMP pulse took out the photocopier (they had unplugged it prior to the storm) and a a couple of computers were damaged (unplugged but on a wired network which acted like an antenna). Would a lighting rod have helped? The EMP would still take out a lot of electronics.
It probably depends a lot on the home construction style in an area and the frequency of lighting. Insurance companies would insist on lighting rods in any area or situation (barn, tower of some kind) where they would produce a significant benefit.
Wire nuts are theoretically ideal, but in practice are error prone, especially for casual, careless, or hurried installers, or when combining dissimilar wires (such as 14-2 solid to a very flimsy stranded wire for a lighting fixture).
And while wire nuts measure as the least resistive compared to push in and lever couplers, the amount of resistive load is not high enough to make a difference for safety or for efficiency, while lacking the clear see through body that allows for easy confirmation of proper wire insulation stripping distance and fully inserted and secured wire that prevents loose wires (shorts or disconnection) and the very real risk of fire starting arcing.
The fact that the push in and lever couplers are faster (time is money) and easily reconfigurable more than make up for the minor increase in cost, a no brainer for anyone that isn't a technophobe or a stubborn "this is how I've always done it" luddite.
Thats why we pull test them before we move on.......the only ones doing this are homeowners and badly trained apprentices.
@@SuperChad1313 yes, with training and vigilance you can use wire nuts just fine, but it's not a perfect world and humans most definitely are not perfect, even professionals, so it remains that wire nuts are now an inferior out dated product where widely available affordable alternatives exist that are better suited to the purpose, with little redeeming qualities to wire nuts beyond industry inertia and reluctance to change.
From an engineer's standpoint it all makes perfect sense. But then I need a special wago for 2 wire connections, one for 3 wire connections, one for 4 wire connections. Wire nuts are more compact and versatile at a fraction of the cost. I keep a few wagos on the truck for certain situations, but I use them sparingly.
I strongly disagree with this demonstration. #14 AWG wire cannot handle 40 A at 120 or 240 Volts. #14 is rated for 15 A at 120/240 V, but only for 80% duty cycle (80% Duration ON with 20% duration OFF in 5 minute increments). All electrical will generate heat. For anything to work, there must be sufficient capability to dissipate the heat, or limit the current to prevent heat generation to the point of destruction. Even with lower voltage (12 to 80 V) driving a stepper motor which has 100% constant on, I will only use #14 AWG wire as 12 Ampere constant on.
I agree. His title was how many amps but no mention of
Volts. So I’ll give him that. But 60 amps at 120v or higher that wire would be glowing. 60 amps at 2 volts is only 120 watts. Vs 7200 watts at 120v. What I don’t like is if some homeowner or handy person who doesn’t understand electrical principles might think they could run 14/2 for say their electric water heater or something with a high current and it will fry. I’d like to see this with a high voltage.
The voltage reading was the voltage drop across the wire with NO LOAD. This was a current control source, not a voltage control source. If you dead short any wire with 120V ac you will certainly get a MUCH MUCH higher than 40 amp current. Like maybe 400-4000 amps. That's why a dead short blows the breaker so fast and throws hot melted metal in your face if you accidentally touch wires in a box. Current control is not generally used so most people don't understand it. We are mostly used to voltage control.
Point being, you will never get 40A at 120V across a dead short. You'd have to have a load to do that. If you put a load (like a light bulb) and it had just the right resistance to make 40 amps at 120V, then the result would be exactly the same as what this video shows. It's the amps the fry it, not the volts.
@@hastypete2 thank you for the the reply I think I may try this experiment. I understand yes. That wire would explode. I’d like to see if that is in fact the case in real world scenario. I can run 14 on a 50 amp breaker powering a heating element out of an air handler.
You missed the point.... 14 gauge is rated to SAFELY be used in a 15 amp circuit.... But you are wrong.... 14 gauge can handle 100 amp in some situations..... He was looking for the failure point in HIS situation.
NEC rates 14 awg NM 15 amp at 120 volts . That's a power rating. Test it at a millionth of a volt and you'll get a bunch of amps before it gets 🔥. It's all about the watts. Run your electric water heater on 120 volts and try to take a hot shower.
The wire is rated for 120V@15 amps. That is around 1800 watts. Your set up is wrong for measuring voltage. The welder at 15-20 amps should still be pushing 20-25 volts or in that ball park. Your grounding clamp should not be touching the ground. My vacuum cleaner pulling 15 amps can get a lot warmer than your set up at 30 amps. Instead of twisting the ends together you need to connect them to a dummy load. Shorting them out is not really a valid test to show how wiring reacts when electricity flows through it.
The cable is probably rated for 600V (this is the insulation rating), so it could theoretically carry 600V*15A = 9kW of power (that is not the same as how much power the cable itself will dissipate as heat). His test setup is fine; he is measuring the voltage drop across the cable which shows him how much power the cable itself is dissipating as heat due to its finite resistance. If the grounding clamp was not connected to ground, there would be no current flow. Where else would it be connected to? The cable can't tell the difference between your vacuum pulling 15A and his test setup pushing 15A through the cable. It all essentially "looks" the same to the cable (the voltage drop would be the same across the cable).
The welder may be designed to operate at those voltages and currents in normal operation, but with it's output shorted with a short length of wire like this it will fail. Ohms law says that the voltage will be the current in amperes multiplied by the resistance in ohms. No exceptions. Your vacuum cleaner gets warmer at 15 amps because the voltage is 300 times higher. Watts is voltage multiplied by current.
@@david672orford Neither the cable nor the vacuum are dissipating 1800 watts as heat. The wire is dissipating much less because its resistance is much lower. The video is demonstrating the amount of power that the cable itself dissipates. The vacuum might heat up, sure, but the majority of the power is being used to create the vacuum, not heat it. Since you're aware what Ohm's Law is, you would have to agree that the cable can't "see" the difference between the the test setup in this video and the vacuum example. With 15A flowing through the cable (in this test setup or the vacuum), the voltage drop across the cable is the same.
@@stuckbreaker8586 Yes, I agree with you completely. The test rig shown in this video produces correct results. Those who keep bringing up how many watts this cable could deliver to a load at 120 volts are confused about what is being measured in watts in this video. And yes, only part of the 1800 watts remains behind in the vacuum cleaner as heat, but it is easily far more than the 21.45 watts which this cable dissipates at 30 amps. So Bryan Rocker should not be surprised that the vacuum cleaner gets warmer.
@@david672orford Agreed, I misunderstood your previous comment and thought you said the test setup was a failure.
In RC aircraft they push more than that, but they are fine stranded, very short and use high temp silicone insulation. It is a tradeoff between power loss as heat and weight.
Good point about that - there is always a tradeoff and your RC case is a perfect example of how different tradeoffs are appropriate for different applications.
According to the instructions for most wire nuts that I can find (actual information from the manufacturers) pre twisting is acceptable but not required for installation.
there's always one in every crowd... a fucking book engineer, just not so good with the real world.
@@chuckholmes2075 You okay?
@@DoRC i was gonna ask you the same thing but I already know the answer
@@chuckholmes2075 I'm okay.
Just throwing this out there, I've been in construction for 15 years, and I've never seen an electrician pre-twist the conductors, before putting on a wire nut. I'm not an electrician, but I have quite a few friends that are, and that just doesn't happen on a typical commercial jobsite.
There was another comment (that I cant find now) from an electrician saying he was specifically taught not to twist them to make it easier to change later (I'm paraphrasing). My comment was maybe it is a regional/local preference one way or the other. I'm in Ontario, Canada and most houses I have lived in (except one) twisting seemed to be the way it was done. Course that's a very small sample set - way smaller than what you would have seen over 16 years in the business. So maybe not twisting is more common.
I work construction and most electricians pre twist as it’s a more solid connection, GC must go for the lowest bid if you rarely see it in commercial
@@Nick-bh1fy That's an interesting comment. I actually did a stress test in another video where I massively overloaded a twisted and untwisted connection and the twisted one was in surprisingly good after 270 Amps. Untwisted not so good, which really supports what you said. Its here if you are interested: th-cam.com/video/Y-2LmKlQW2A/w-d-xo.html
@@ElectromagneticVideos the way I was taught was the marrette is only there to insulate the connection and not act as a physical bonding connection between multiple conductors. I strip wires slightly longer, twist from the end and cut off the copper that has been nicked and you’ll have a connection that won’t come apart.
@@Nick-bh1fy Sounds like a real quality way to do it. The wire spring thing in the standard marr type connector really seems quite flimsy, particularly with the softer plastic used today. The old black ones with much more rigid plastic probably could exert more force on the wires, but even then I'll bet your technique would produce a much better connection.
A large toaster.
Stopped watching at 1:21 after improper installation of the wire nut, see manufacture instructions.
If you mean because I pre-twisted the the wire, pre-twisting or not is a manufacturer specific thing and it seem like half the electricians pre-twist and half dont.
As a commercial tech. I was taught and always pre twist, just like every credible tech I meet.
A bad connection is a hot connection and is likely to melt and burn. If you haven’t found melted wire nuts then you haven’t a clue of its importance
@@supabiscuit I completely agree with you! But you wouldn't believe the (or maybe you would) the number of people who vehemently argue against it. Seems like electricians are divided 50-50 on the subject.
@@supabiscuit Heat sure is an indication of bad connection. I would guess that with thermal imaging cameras getting so common place nowadays many more bad connections are getting found before something bad happens these days than they use to.
Rated at 15 amps, which is about 20% less than what it can really handle. There are amp ratings PER HOUR for every wire we can use.
I think appliances are rated for 1250 watts or about 1/2 of what the wire can really handle.
A good splice on wire is created by mechanically joining the wire, solid or stranded. The 'wire nut' is just there to replace the insulation if the wires are properly twisted together first. 3M Red/Yellows are my favorites, but I never rely on them to make the splice. Strip, pinch and twist, then cap the splice with a good wire nut.
The wire nut does twist as well, and bites on to the softer copper. There are arguments both ways as which is better.
It says not to twist first
@AgentOffice I've only been an electrician for 40 years. Splices that are twisted tight first then capped do not come apart. Just write nutted? Those are the fails that result in call backs to fix.