A co worker would torque wires above #8. Then shake them halve hour late to what he called settling in the many strands then performing a little more torque.While performing quarterly PM on a year old 200 HP fire pump found several factory installed wires on a starter 40 degrees hotter then room tempetature due to not being torqued enough. As an apprentice we were taught to never trust tightness of factory made panels. Ones shipped across the ocean always were the worst. We retorqued every connection including wires on start stop buttons. Thanks for another great vid. Observed many techs & service companies performing maintenace on 480, 4,160 & 13,200 volt equipment never using a torque wrench.
The part about tightening a second time, in my experience with al and it's ability to appear tight but actually be loose, I always have the electricians re-tighten. Too many times I've seen al mechanical connections that appear tight and in reality they are not (and they fail spectacularly). I deal with uniterruptible power systems and until very recently al wasn't an option we allowed due to the tightening issue, unless compression lugs were used. Interesting information overall, thanks!
Worked at a large slaughterhouse years ago where we always installed lockwashers on all bolts ( stakon splices motor bases etc ) due to a lot of vibration by crushers hammer mills skakers etc. Made sure all connections were made super tight. Had to get use to not breaking heads off of 1/4" hex headed screws while tightening with a breaker bar.
Thank you Ryan. I have been doing maintenance- electrician- at a zoo for about ten years. Probably 90% of the electrical equipment is from 1986-87. I’m a little embarrassed to say I HAD gotten into the habit of “ red-faced torquing” . You know, just short of popping a vein. A lot of what I do is trying to maintain our existing equipment so again.....thanks. Doug.
Over tightening bolts & screws not a good thing. When I was a young strong apprentice would drive my coworker crazy breaking 1/4" by applying too much force. While at an IAEI class the instructor told us that UL went around and checked torque on various connections. Only 30% were correct and think it was 50% too loose and remainder over torqued.
I worked for a large commercial electrical contractor in Florida I was assigned to build switch gear. When I asked the shop for a torque wrench , they didn’t even know what I was talking about! None of them! They looked at me like I was into voodo/ black magic. For real! Scary willful ignorance.I hated that place.
How many mechanics don’t torque bolts when changing wheels or even basic bolts? I can’t tell you how many people have warped brake rotor’s or rounded heads because of it. When you consider most lugs in a panel or receptacle will not be touched again for decades, why not take the time to do it right.
I’m glad to see the code start addressing this a bit further. Before I retired I spent the last 8 years of my career as an electrician in a specialist role where there were four of us that did all of the check outs and commissioning of new installations, power distribution and substation maintenance, and infrared pm’s of all of the electrical equipment in a large chemical plant with about 2000 employees. The number one problem we found was improper torquing of terminations! And twice we had to have an unplanned emergency shutdown of a facility because of inadequately tightened horizontal buss splices in brand new installations of Allen Bradley motor control centers. It doesn’t look good when you convince a plant superintendent to spend $250,000 to tear out an old overhead exposed buss with rack mounted disconnects and starters that’s been working fine for 50 years and replace it with a new MCC that fails in 48 hours. The most common poor connections we found were breaker terminations in lighting panels and motor lead terminations in motor control centers.
Except most of those torque wrenches must be sent off for factory calibration every year or so depending on use. That is what will trip most people up. Either the company must maintain a policy with spares or the individual must have 2 so one can be sent off every year.
Before I retired a few years ago my very smart senior electrician showed me one of his electrical books ( not the NEC ) told you that you should never retorque wires that were torqued. We had an on going arguement with the cheief electrician who insisted that we retorque every connection every time we performed a 6 or 12 month PM on hundreds of VFD'S that were running. At that time nobody made an insulated torque wrench so even with PPL refused to do it unless the drive ccould be shut down & LOTTO.
As a building inspector, they had to go work as a millwright when we had to crash in 2008. Well I found is electricians do not tighten things tighten enough. I found loose lugs loose wire nuts and some poor installations. It’s nice to be back as inspector since 2013. But that short time off taught me that I need to pay more attention to what the guys are doing out in the field.
Ryan, thank you for all you do to teach us the code in a very down to earth way. Is there anyway you could cover 110.14 (C)? There is much confusion in my area with temperature rating and ampacities. An explanation of this code would be very helpful. Thank you!
Wow! Thanks for the clarification, I did not know that. Waste my time, please! I'll be busy learning from you. I'm at the beginning of my electrician journey. I want to be a very good electrician.
Informative. I was always taught "snug, not crush". Being part of the "younger" generation of electricians I try to get rid of the old bad habits or the accepted bad practices others have allowed, so I'd went out and bought a torque wrench. Read the directions, tried it on a small meterbase to their specified value, and promptly stripped the lug. That was the first and last time I tried using any torque wrench.
@@MrMaxyield Yea, but my point was that more and more electricians are using Wagos. The double standard is calling out the Backstabbers as hacks yet using Wago connections.
Food for thought. On several panels that I know were torqued a year earlier had hot breaker terminals under load when viewed by FLIR thermal imaging. All popular brand breakers with both solid and stranded copper wire. The they were re torque and the heat went away. Pulling and inspecting a twice torqued conductor shows no excessive signs of damage,pinch off, extrusion. Only good contact area. Soft metal cold flows and 85% is initially, the rest comes later, but it greatly reduces and is not indefinite unless there conductor/terminal aren’t compatible or sized correctly. One lifetime torque is BS and a great way to service call. I predict the NEC will address it better. For the first tightening on stranded is to gently orbit the wire as I come up to torque to help settle the strands. Makes hell of a difference in integrity of the connection.
Also for mechanical torque wrenches they are usually recommended to be unloaded when not in use. Don't leave the torque value set over time it will stretch the spring and throw off the value.
I've heard that for air compressor regulators too. there may be some truth to it, not really sure, but... it's a tool, so yes. be good to your tools and they will be good to you. I think it really depends on the design of the tool. metal fatigue is a real thing.
For normal torque wrenches with a turn handle. There are some that this doesn't apply to. I'm a a car mechanic. We have a tire torque wrench that doesn't require turning it down. It uses a different setup.
That is a GREAT question. The way I always answer it is to refer to 8.11 of 70B and do the 90% test. Anything beyond that could easily be viewed as a destructive test.
@@RyanJacksonElectrical so, inspectors could test for undertorqued, but not for overtorqued, without marking and releasing and retorquing... which wouldn’t be accurate either... since the conductor would be over compressed by the original overtorquing...
Still, never will use aluminum other than service conductors, some large feeds, that is where the copper clad may benifit, but CCA still needs to be treated as aluminum, is more brittle, termination torque etc, I will never use CCA for any branch circuit installation. After having dealt with some of the AU home wiring back in the day and those problems, never would I ever install it now, even if copper cladded. Same for low voltage (reference data/security etc) had gotten some CCA wiring for some data, security was cheaper did not notice, eventually so many issues with failed termination, I ripped out what had installed, got pure copper no problems, basically all that CCA when to the dump where belongs! Learned my lesson with that costed me, the money wasted on the wire, the time redoing stuff. I do not want call backs and have no time for installation issues either. Just not going to be part of my inventory.
Like how some switchgear manufacturers mark heads of all hex headed bolts with a marker. By looking at original drawn line between bolts and buss bar or breaker connection easy to see if connection came loose.
And if I am working in the panel, - do I have to remove every component to look for the torque value of each of it, because it is not visible from the front, to find out what is 90% of the required torque value is?
I would imagine that the skin effect is very slight with only 60 cycle current and that the real reason for the diminishing returns with larger conductors is the diminishing surface area to volume ratio. The volume is responsible for the generation of heat, but that heat can only dissipate via the available surface area.
Most likely not that much effect at that low of frequency, probably some but doubt it I think the most obvious reason for CCA is cost period as the major driving factor.
Most of current travels near the surface of the wire. With larger wires you can theoretically get more current capacity for less money by cladding aluminum with copper. The current cost of materials and cladding will dictate when it makes sense. Of course I would rather have copper only and not worry about issues with aluminum. Back in the 1960s I worked with circuit boards that had silver or gold conductors, not that anyone could afford gold for wiring a structure
sheer bolts common for "donuts" or "biscuits" that connect multi family meter packs next to each other. the head breaks off, and a colored plastic washer is left behind that shows its been torques.
Some meter cans broke way to easy. But haven’t had that problem in a long time. Perhaps there was a time they were defective. Because I’ve seen many lose connection it isn’t funny.
are they plastic? I watch videos of electricians in some european countries... who what........ I don't even know...... main circuit panel for houses, all plastic, box and all..... and the work they're doing in the video is to replace the previous circuit panel which is now missing, bits of charred plastic hanging from the wires. wow.. code books and local laws say this is ok.
I’m installing a temporary electric pole for my home construction. I ran copper to the meter base and I am running aluminum to the top of meter base for power company hook up to. I s that ok ?
The engineering term is creep. The metal literally flows like a liquid under stress over long time periods. The higher the stress the faster. So under a screw the contact points are extremely high stress, and will flow a bit to relax that stress in a short time. Interestingly if you have a small leak in gas NPT fittings leaving them for a week they often creep and will seal up.
I should try to using the correct terminology as well. I believe the correct term would be "MECHANICAL SHEAR BOLT TERMINAL LUGS". I also found out that they are used by some manufacturers for medium voltage terminal connectors, such as cold shrink and heat shrink kits.
BTW, the MFG of the termination, as far as I know, does not specify strand count. There is a missing link in that regard. Degradation in this case is that the wire just falls out. No, MFG spec is not good enough for low-strand count cables. Crimp lugs only. SAB cable. Great prices but you better crimp and not skimp.
Most every day MECHANICAL lugs are listed compatible with Class A & B stranding only. A & B is the ordinary building wire we use every day. Class C & D stranding are the highly stranded conductors like welding cable. As far as I know only compression lugs are available for Class C & D
I've always wondered about these torque tools when it comes to the do-it-yourselfer. It's not like you can pick up these things at Walmart. I'm not even sure if Home Depot or Lowes sells them. I've looked on the Internet, and they are not cheap. Exactly how is an inspector supposed to know it was torqued properly if it doesn't have sheer bolts? All you've got is the honor system. They'll probably make you torque wire nuts properly too. I seems to go in the category of arc fault receptacles and breakers. Just something not necessarily proven that you have to buy.
Pretty sure the lug pictures around 3:45 is aluminum, not steel. I have never seen a steel one ,and it wouldn't make sense to use steel due to the higher resistance, differences in thermal expansion and lack of corrosion resistance (they would have to galvanized). The skin effect for current really isn't significant at 50/60Hz. The skin is about 8.5mm thick so no home wiring is large enough to not have the current flowing thru the entire wire cross section. Please don't suggest using torque indicating screws. They are one time use, and very expensive. Fix problems that actually exist. We aren't having failures of these connections so don't add cost by more complex hardware or inspection requirements.
That is an aluminum lug. A tin-coated aluminum lug. It is common to use tin-coated aluminum for lug materials, and for them to be rated for use with both copper and aluminum wire with an appropriate antioxidant for aluminum. Because of copper having a higher thermal expansion coefficient than aluminum, it is common for aluminum lugs to be dual rated for both materials but copper lugs are exclusively for copper wire. You want the wire to tighten its contact with the lug as it heats up, rather than loosen the lug.
I've never seen a torque specification I liked. Most local switchgear hasn't even got one, but then you get the European stuff (*cough* Gave *cough*) that tells you 0.2Nm, but has space for anything between 1mm² finely stranded to 16mm² solid.
@@madzmadeit Oxidation and the ability to be complaint with copper only terminals, which are numerous. Also for CATV drop cable they use copper clad steel. The reason is the steel core is very strong and can support the cable for long runs. At the frequencies involved, the copper coating is all that is needed to carry the signal due to skin effect. At those frequencies the signal rides on the conductor surface with little penetration into the center of the conductor.
@@andydelle4509 thank you for being one of the few to get that right. it's interesting to see how the big old tv transmitter stations work. the huge cables that go from the transmitter to the tower are actually all just hollow pipes, almost like plumbing pipes. very thin wall. then they vacuum down the pipes to lower the capacitance of the cables. interesting but beyond me. I think where people get confused, they hear about this skin effect and assume it's all electricity. one real reason why cables get so big, diminishing returns on size, it's the heat dissipation. the bigger the cable, the less surface area it has relative to the cross-sectional area.
it's like working on a car with all plastic parts in the engine compartment. you tighten down a bolt until you hear the crack, then back a quarter turn, perfect!
My only disagreement after watching the video is to only torque once. I've followed those electricians around far too often. One of my first lessons in the field was to always retorque connections, specifically every stranded wire connection. The stranded conductors will "settle" and should be re-torqued 24 hours later.
First, that terminal block is made from aluminum, and not steel as you stated. Second, if your skin effect argument was true, the ampacity of CCA would be higher than that of aluminum wire, but it is not (at least, at 60Hz), as the skin depth at normal utility frequency is far deeper than the thickness of the copper plating.
The ampacity of copper-clad aluminum IS greater than aluminum. That is not my opinion, that is a fact. When CCA is created it becomes a bimetal with different characteristics than copper or aluminum. The ampacity of the product lies between the two. The values in Table 310.16 are not going to be changed, however, because creating an ampacity table showing an ampacity table of 17A, for example, would be of no benefit.
soon they will add next changes as well for dipping some coating for copper strands for number 10 to 6 for subpanels and as well for ac disconnect switch..are we overdoing the safety..i am sure coating with wire goo would not rust the wires...but what cost doing so ?? its only 30AMPS to 60AMPS
@@SuperVstech any amperage is dangerous for your heart...BUT NOT WITH SCREWS THAT GRAB THE WIRE TIGHT..TORQUE SPECS IS BS..i usually never over-tighten..longest i can tell the stranded wire is not wobbling at the screw lugs..you are good to go for installing breakers and final test of turning on the feeder breaker from main panel..JUST RELAX...everything is grounded correctly for both panels...1st pane,l I always check its bonded first before 2nd or 3rd panel are not..its right order and both detached from home and garage area/storage room have each ground rod...we are safe
@@user78405 wow... apparently you are an expert on wire contingency... code should just ask you for safety and consequences be damned... torque specs aren’t there for grounding issues, or hear stopping faults... It’s there to prevent fires. Improper conductor securing can cause building fires.
Damaging the conductor, damaging the damaging the terminal, damaging the equipment. No, there is no such requirement because the NEC ends at the installation [90.2(A)]. Maintenance is not within the scope. See NFPA 70B for recommended maintenance practices.
bolts stretch when they are over-tightened. they can also stretch somewhat when they're properly tightened, hence why there's a specific torque. an engineer figured the exact amount that bold should stretch to be as secure as it can be, without the risk of damaging the metal. if you keep making a bolt tighter and tighter, you get to a point where not only does it not tighten more, it'll start to fail and give way. most times in the world, good is good enough. but with electrical installation, much of the time you want that install to absolutely never fail. sometimes guessing with your own strength isn't good enough.
@@lorenzo42p I'm 60 years old and have been working in the repair field most of my adult life and even as a youngster growing up on a farm to a certain extent. I spent several years in related schooling. I'm very familiar with bolt stretch. I'm also very familiar with the fact that there's a difference in bolts. All that being said, it's really not realistic to think that screws in a 60hz ac system is only going to ever need tightened once. Not one time in my entire life have I had a connection fail because I didn't tighten it correctly. The only problem with connections is from a less than desirable tech and using a torque wrench isn't going to fix that. It will only hurt the ones that didn't need to use it in the first place.
@@engineclinic I want to prove you wrong,. But, I can't. There are estimates. Estimates don't prove much. However, there really isn't any other data, because in 1980, statistics weren't really that concise. I am a better safe than sorry type. The estimates are that there are currently half as many fires caused by electrical malfunction than there were in 1980, when you began. However, most electrical fires are NOT caused by poor quality in workmanship. In fact, it doesn't even rank in the top 7. Aging equipment, DIY repairs, turkeys, overloads, heaters, and extension cords all made the list. If I were to guess, if the 50% estimate were remotely true, it has very little to do with over or under torqueing connections. It probably has more to do with organizations like the NFPA creating awareness of the dangers of things like turkeys and tip switches on heaters. You can't educate the DIY'ers anymore than they choose to be, but I think that currently the DIY'er is a bit more savvy than they were 40 years ago. A lot of that has to do with the availability of information.
electricity doesn't flow mostly around the outside of a wire, that's mythical bull. that only applies to high frequency, which power lines are closer to dc than they are to a high frequency. the real reason you have diminishing returns on larger cables is the surface area, yes, but for different reasons. heat dissipation. that is also a reason why animals can't get much bigger than an elephant and why smaller animals have a much faster metabolism, surface area to get rid of waste heat. electricity flows for the most part evenly through the entire area of a cable. a down side of copper clad, it creates more heat internally, which needs more surface area to dissipate, which means a much bigger cable.
Goto any commercial construction site an find me electrician that has a calibrated torque wrench/screw driver. Then see if it looks used. Anyways love the idea but it’s only practical if you pay to have someone sign off on every panel during final install. (QA engineer) Most jobs can’t justify the cost.
Ooof! Control panel wire...especially power wires, depending on the termination type(mechanically) depend soo much on strand count. A-B is the worst, IMO and ABB is the best. Nonetheless, course(low strand count) wires must be terminated with crimp lugs. Else, you could tighten them every hour and find that they are loose no matter the torque. VFD cable is good example. Low strand count is cheaper but demand crimp connectors plain and simple.
Alot issues to consider here Hitachi no login here squeal thinking that's too tight odds are the thread just broke cad aluminum and copper wire torque the same ? regardless the lug material the problem is the lug itself the manufactured should require a torque setting on the lug another thing to consider is does bolt or nut stretch , torque It loosen it up and torque it again and yes moving wire round when it comes to bus duct bus bars 480 hanging bar system with removable buckets around the room most buckets were 30 to 60 amps the manufacturer required to be retighten every year and I would think that would go to the account of room temperature Four Seasons minimum maximum voltage draw vibration of the system we torque bolts about every two years and mark the bolts with different pin colors different years So when you say doing maintenance torque it one time and that's good enough leave regardless what that books reads ask yourself why don't Transformers come with lugs but they'll give you torque settings leave it up to the electrician to get you the bolts and nuts the washers and that great shit from the supply house from China which many lugs should have a torque setting and don't tell me to go to the manufacturer website and try to figure it out it all comes down to liability the Transformer , electrician , lug manufacturer, code book.,,,, how long is the warranty good for lol. Thanks for the discussion when you asked your inspector he reply why you asking me about proper torque settings ? He'll answer Don't put me in that situation lol
code should be a guide, not end-all be-all. my opinion, and why I don't like "code". most people don't understand the reasons why code says to do it one way and not another. even in this video he got some things wrong.
Hate to be a noodge....It's Pounds Inch, I know Inch Pounds is commonly used, just like people often erroneously say Foot Pounds.....BUT,,,details matter, and you seem to be a detail guy, just a little bit,. Torque = force x distance, like Newton Meters....not Meters Newton.
“ properly calibrated “ haaa….Nothing should ever be assumed is obvious, when dealing with humans who are paid to hurry… are you kidding me.. that’s like saying it’s obvious we need to wear seatbelts , so who needs a rule to enforce it..
Codes are always changing just so the kids in school will have to buy new books and longer the length of time that one has to attend school to graduate.... take the test pass and get the patch... just like every other degree in colleges.... add more books add more time for the degree and of course add more dollars to attend...! then graduate....
As a electricain who knows it all. When I watch your channel I find how much I don't know at all
Videos like these are excellent reminders to those who care about their work quality. Thank you, sir 👍
A co worker would torque wires above #8. Then shake them halve hour late to what he called settling in the many strands then performing a little more torque.While performing quarterly PM on a year old 200 HP fire pump found several factory installed wires on a starter 40 degrees hotter then room tempetature due to not being torqued enough. As an apprentice we were taught to never trust tightness of factory made panels. Ones shipped across the ocean always were the worst. We retorqued every connection including wires on start stop buttons. Thanks for another great vid. Observed many techs & service companies performing maintenace on 480, 4,160 & 13,200 volt equipment never using a torque wrench.
When working with stranded wiring in lugs I always give it a wiggle and torque it twice!
Yes people, a wiggle. I do the same,especially with stranded wire. #8 and bigger, wiggle, strands place themselves and I retorque
Wise advice! I'll guess this is the factor that will always trump exacting torque.
the information you put out is great i am addicted to your videos
The part about tightening a second time, in my experience with al and it's ability to appear tight but actually be loose, I always have the electricians re-tighten. Too many times I've seen al mechanical connections that appear tight and in reality they are not (and they fail spectacularly). I deal with uniterruptible power systems and until very recently al wasn't an option we allowed due to the tightening issue, unless compression lugs were used.
Interesting information overall, thanks!
Excellent! There is very little information on this subject and that was about the best summary I’ve ever seen. Thanks
Worked at a large slaughterhouse years ago where we always installed lockwashers on all bolts ( stakon splices motor bases etc ) due to a lot of vibration by crushers hammer mills skakers etc. Made sure all connections were made super tight. Had to get use to not breaking heads off of 1/4" hex headed screws while tightening with a breaker bar.
Thank you Ryan. I have been doing maintenance- electrician- at a zoo for about ten years. Probably 90% of the electrical equipment is from 1986-87. I’m a little embarrassed to say I HAD gotten into the habit of “ red-faced torquing” . You know, just short of popping a vein. A lot of what I do is trying to maintain our existing equipment so again.....thanks. Doug.
Over tightening bolts & screws not a good thing. When I was a young strong apprentice would drive my coworker crazy breaking 1/4" by applying too much force. While at an IAEI class the instructor told us that UL went around and checked torque on various connections. Only 30% were correct and think it was 50% too loose and remainder over torqued.
Excellent video, just showed this to the maintenance staff during training for the 70B.
I worked for a large commercial electrical contractor in Florida I was assigned to build switch gear. When I asked the shop for a torque wrench , they didn’t even know what I was talking about! None of them! They looked at me like I was into voodo/ black magic. For real! Scary willful ignorance.I hated that place.
Typical for ropers who moved into commercial
How many mechanics don’t torque bolts when changing wheels or even basic bolts? I can’t tell you how many people have warped brake rotor’s or rounded heads because of it. When you consider most lugs in a panel or receptacle will not be touched again for decades, why not take the time to do it right.
Thank you, Ryan, for doing the deep dive, 90% rule is now knowledge I did not have.
Thank you Ryan for yet again another awesome video.
What a nice way to explain these concepts. Nice and easy. Wonderful video. Thanks for your class.
If you can’t tell from all of the recent likes on your videos, I have found your channel & am now subscribed. Thank you for uploading!
Thank you!
I’m glad to see the code start addressing this a bit further. Before I retired I spent the last 8 years of my career as an electrician in a specialist role where there were four of us that did all of the check outs and commissioning of new installations, power distribution and substation maintenance, and infrared pm’s of all of the electrical equipment in a large chemical plant with about 2000 employees. The number one problem we found was improper torquing of terminations! And twice we had to have an unplanned emergency shutdown of a facility because of inadequately tightened horizontal buss splices in brand new installations of Allen Bradley motor control centers. It doesn’t look good when you convince a plant superintendent to spend $250,000 to tear out an old overhead exposed buss with rack mounted disconnects and starters that’s been working fine for 50 years and replace it with a new MCC that fails in 48 hours. The most common poor connections we found were breaker terminations in lighting panels and motor lead terminations in motor control centers.
Very slight correction around 5:40, 380 to 665 is a 75% increase (1.75*380=665)
Except most of those torque wrenches must be sent off for factory calibration every year or so depending on use. That is what will trip most people up. Either the company must maintain a policy with spares or the individual must have 2 so one can be sent off every year.
Most people just tighten it as tight as possible and mark it with a sharpie
@@crack1270 did you watch the video? That's just as bad, and the reason i do my own work.
Your electrical and code explanations are so on-target.....
I’m waiting for your spectrum analyzer/ 2-way radio duplexer tuning video series..
😷😀👍🏻
but it's not all exactly true. I'm definitely not always right either, but it's great to learn.
Good info in this video.
Too many do not want to understand this important concept.
Before I retired a few years ago my very smart senior electrician showed me one of his electrical books ( not the NEC ) told you that you should never retorque wires that were torqued. We had an on going arguement with the cheief electrician who insisted that we retorque every connection every time we performed a 6 or 12 month PM on hundreds of VFD'S that were running. At that time nobody made an insulated torque wrench so even with PPL refused to do it unless the drive ccould be shut down & LOTTO.
As a building inspector, they had to go work as a millwright when we had to crash in 2008. Well I found is electricians do not tighten things tighten enough. I found loose lugs loose wire nuts and some poor installations. It’s nice to be back as inspector since 2013. But that short time off taught me that I need to pay more attention to what the guys are doing out in the field.
Ryan, thank you for all you do to teach us the code in a very down to earth way. Is there anyway you could cover 110.14 (C)? There is much confusion in my area with temperature rating and ampacities. An explanation of this code would be very helpful. Thank you!
I'll put it on my to-do list.
Wow! Thanks for the clarification, I did not know that.
Waste my time, please! I'll be busy learning from you. I'm at the beginning of my electrician journey. I want to be a very good electrician.
Always enjoy your information. Keep posting
Thanks Ryan for clarification.
Ge and Eaton both have breakaway boltheads, and the torque indicating color changing heads. Pretty neat
The terminal in the first picture is actually aluminum not steel. It's very rare that you see a steel lug
Informative. I was always taught "snug, not crush". Being part of the "younger" generation of electricians I try to get rid of the old bad habits or the accepted bad practices others have allowed, so I'd went out and bought a torque wrench. Read the directions, tried it on a small meterbase to their specified value, and promptly stripped the lug. That was the first and last time I tried using any torque wrench.
A snug not crush mentality seems ludicrous to me. I don't see how you can get a connection too tight.
its funny that the code requires torque values and yet we still can stab 14 gauge wire in the back of switches and receptacles
And....
More and more electricians are using wagos and praising them.
Wago is a backstab receptacle
True although any electrician worth his salt knows backstabbing is for hacks...
@@MrMaxyield
Yea, but my point was that more and more electricians are using Wagos.
The double standard is calling out the
Backstabbers as hacks yet using Wago connections.
@@itaintrocketscience I agree.. they're essentially the same...
Not at all
Another very informative video.
Thanks for sharing your knowledge.
Food for thought. On several panels that I know were torqued a year earlier had hot breaker terminals under load when viewed by FLIR thermal imaging. All popular brand breakers with both solid and stranded copper wire. The they were re torque and the heat went away. Pulling and inspecting a twice torqued conductor shows no excessive signs of damage,pinch off, extrusion. Only good contact area. Soft metal cold flows and 85% is initially, the rest comes later, but it greatly reduces and is not indefinite unless there conductor/terminal aren’t compatible or sized correctly. One lifetime torque is BS and a great way to service call. I predict the NEC will address it better. For the first tightening on stranded is to gently orbit the wire as I come up to torque to help settle the strands. Makes hell of a difference in integrity of the connection.
According to my calculations, going from 380 Amps to 665 Amps is a 75 percent increase, not 59 percent. Am I missing something? Thanks.
Thank you, came to post the same thing.
by my math, 380 is 57% of 665. not sure where 59% comes from. 665 is 175% of 380, so you are right, it's a 75% increase over the original 100%.
Yep, agreed. My bad. I had that number in my head for whatever reason.
@@RyanJacksonElectrical No problem. Either way you still gave us the concept. Thanks.
@@RyanJacksonElectrical very common mistake, happens all the time. Thanks for the great video.
Also for mechanical torque wrenches they are usually recommended to be unloaded when not in use. Don't leave the torque value set over time it will stretch the spring and throw off the value.
I've heard that for air compressor regulators too. there may be some truth to it, not really sure, but... it's a tool, so yes. be good to your tools and they will be good to you. I think it really depends on the design of the tool. metal fatigue is a real thing.
For normal torque wrenches with a turn handle. There are some that this doesn't apply to. I'm a a car mechanic. We have a tire torque wrench that doesn't require turning it down. It uses a different setup.
I do have a quick question. How would a inspector verify that proper torque was performed on circuit breakers?
That is a GREAT question. The way I always answer it is to refer to 8.11 of 70B and do the 90% test. Anything beyond that could easily be viewed as a destructive test.
@@RyanJacksonElectrical so, inspectors could test for undertorqued, but not for overtorqued, without marking and releasing and retorquing... which wouldn’t be accurate either... since the conductor would be over compressed by the original overtorquing...
@@SuperVstech Agreed. To the best of my knowledge, the only totally accurate way to inspect it is to witness the termination.
@@RyanJacksonElectrical usually they just want us to show them the torque wrench as proof.
@@galaxybounce82 "...Yea, we torqued it" ok here's your green sticker
Still, never will use aluminum other than service conductors, some large feeds, that is where the copper clad may benifit, but CCA still needs to be treated as aluminum, is more brittle, termination torque etc, I will never use CCA for any branch circuit installation. After having dealt with some of the AU home wiring back in the day and those problems, never would I ever install it now, even if copper cladded. Same for low voltage (reference data/security etc) had gotten some CCA wiring for some data, security was cheaper did not notice, eventually so many issues with failed termination, I ripped out what had installed, got pure copper no problems, basically all that CCA when to the dump where belongs! Learned my lesson with that costed me, the money wasted on the wire, the time redoing stuff. I do not want call backs and have no time for installation issues either. Just not going to be part of my inventory.
not sure the book can take more pages next...we be running out page numbers soon
Like how some switchgear manufacturers mark heads of all hex headed bolts with a marker. By looking at original drawn line between bolts and buss bar or breaker connection easy to see if connection came loose.
And if I am working in the panel, - do I have to remove every component to look for the torque value of each of it, because it is not visible from the front, to find out what is 90% of the required torque value is?
Any recommendations for a good torquing screwdriver?
Wiha
I would imagine that the skin effect is very slight with only 60 cycle current and that the real reason for the diminishing returns with larger conductors is the diminishing surface area to volume ratio. The volume is responsible for the generation of heat, but that heat can only dissipate via the available surface area.
Most likely not that much effect at that low of frequency, probably some but doubt it I think the most obvious reason for CCA is cost period as the major driving factor.
Most of current travels near the surface of the wire. With larger wires you can theoretically get more current capacity for less money by cladding aluminum with copper. The current cost of materials and cladding will dictate when it makes sense. Of course I would rather have copper only and not worry about issues with aluminum. Back in the 1960s I worked with circuit boards that had silver or gold conductors, not that anyone could afford gold for wiring a structure
sheer bolts common for "donuts" or "biscuits" that connect multi family meter packs next to each other. the head breaks off, and a colored plastic washer is left behind that shows its been torques.
I’m part of the 20%. My connections are always very tight. I’ve broken many a meter cans....
LOL
Some meter cans broke way to easy. But haven’t had that problem in a long time. Perhaps there was a time they were defective. Because I’ve seen many lose connection it isn’t funny.
I’ve broke two, but not for a few years now.
are they plastic? I watch videos of electricians in some european countries... who what........ I don't even know...... main circuit panel for houses, all plastic, box and all..... and the work they're doing in the video is to replace the previous circuit panel which is now missing, bits of charred plastic hanging from the wires. wow.. code books and local laws say this is ok.
I’m installing a temporary electric pole for my home construction. I ran copper to the meter base and I am running aluminum to the top of meter base for power company hook up to. I s that ok ?
thank you so much for this informative topic.
Is the reason for metal relaxation is that copper and aluminum is elastic in nature
The engineering term is creep. The metal literally flows like a liquid under stress over long time periods. The higher the stress the faster. So under a screw the contact points are extremely high stress, and will flow a bit to relax that stress in a short time.
Interestingly if you have a small leak in gas NPT fittings leaving them for a week they often creep and will seal up.
@@court2379 Good info thank you
Very well explained
Yes. Most failures by far are in conection points
Some manufactures are using "snap off" bolts for their bus duct systems.
I should try to using the correct terminology as well. I believe the correct term would be "MECHANICAL SHEAR BOLT TERMINAL LUGS". I also found out that they are used by some manufacturers for medium voltage terminal connectors, such as cold shrink and heat shrink kits.
BTW, the MFG of the termination, as far as I know, does not specify strand count. There is a missing link in that regard. Degradation in this case is that the wire just falls out. No, MFG spec is not good enough for low-strand count cables. Crimp lugs only. SAB cable. Great prices but you better crimp and not skimp.
110.14 addresses finely stranded conductors, and Table 10 (off the top of my head) addresses strandings.
Most every day MECHANICAL lugs are listed compatible with Class A & B stranding only. A & B is the ordinary building wire we use every day. Class C & D stranding are the highly stranded conductors like welding cable. As far as I know only compression lugs are available for Class C & D
My wrist clicks. Retired IBEW 292.
Is that terminal really made of steel? Or a steel alloy? It seems kind of lightweight, to be steel.
Aluminum.
@@RyanJacksonElectrical With tin plating. Some bus bars use nickel for higher expected temperatures.
That was Torquing by hand all these years
Aren't most mechanical lugs made out of aluminum?
I've always wondered about these torque tools when it comes to the do-it-yourselfer. It's not like you can pick up these things at Walmart. I'm not even sure if Home Depot or Lowes sells them. I've looked on the Internet, and they are not cheap. Exactly how is an inspector supposed to know it was torqued properly if it doesn't have sheer bolts? All you've got is the honor system. They'll probably make you torque wire nuts properly too. I seems to go in the category of arc fault receptacles and breakers. Just something not necessarily proven that you have to buy.
Arc fault is code for all bedrooms in many areas.
Pretty sure the lug pictures around 3:45 is aluminum, not steel. I have never seen a steel one ,and it wouldn't make sense to use steel due to the higher resistance, differences in thermal expansion and lack of corrosion resistance (they would have to galvanized).
The skin effect for current really isn't significant at 50/60Hz. The skin is about 8.5mm thick so no home wiring is large enough to not have the current flowing thru the entire wire cross section.
Please don't suggest using torque indicating screws. They are one time use, and very expensive. Fix problems that actually exist. We aren't having failures of these connections so don't add cost by more complex hardware or inspection requirements.
That is an aluminum lug. A tin-coated aluminum lug.
It is common to use tin-coated aluminum for lug materials, and for them to be rated for use with both copper and aluminum wire with an appropriate antioxidant for aluminum. Because of copper having a higher thermal expansion coefficient than aluminum, it is common for aluminum lugs to be dual rated for both materials but copper lugs are exclusively for copper wire. You want the wire to tighten its contact with the lug as it heats up, rather than loosen the lug.
I've never seen a torque specification I liked. Most local switchgear hasn't even got one, but then you get the European stuff (*cough* Gave *cough*) that tells you 0.2Nm, but has space for anything between 1mm² finely stranded to 16mm² solid.
Please consider creating a "deep dive" video or series of videos into NFPA 70 Article 760 Fire Alarm Systems.
Thanks!
Lawyers and insurance companies at work stressing torque issues...
Thanks!!!!
Just FYI, skin effect is negligible at 60hz.
Then what would explanation be for using a copper coating?
@@madzmadeit Oxidation and the ability to be complaint with copper only terminals, which are numerous. Also for CATV drop cable they use copper clad steel. The reason is the steel core is very strong and can support the cable for long runs. At the frequencies involved, the copper coating is all that is needed to carry the signal due to skin effect. At those frequencies the signal rides on the conductor surface with little penetration into the center of the conductor.
@@andydelle4509 Thank you 🙏
@@andydelle4509 thank you for being one of the few to get that right. it's interesting to see how the big old tv transmitter stations work. the huge cables that go from the transmitter to the tower are actually all just hollow pipes, almost like plumbing pipes. very thin wall. then they vacuum down the pipes to lower the capacitance of the cables. interesting but beyond me.
I think where people get confused, they hear about this skin effect and assume it's all electricity. one real reason why cables get so big, diminishing returns on size, it's the heat dissipation. the bigger the cable, the less surface area it has relative to the cross-sectional area.
I agree that frequency is the biggest contributor to skin effect. Copper clad steel was originally manufactured for that purpose.
Tighten it till cracks, back it off a 1/4 and leave it for the night shift.
Why would you back it off?
it's like working on a car with all plastic parts in the engine compartment. you tighten down a bolt until you hear the crack, then back a quarter turn, perfect!
@@engineclinic it's a joke :-P
My only disagreement after watching the video is to only torque once. I've followed those electricians around far too often. One of my first lessons in the field was to always retorque connections, specifically every stranded wire connection. The stranded conductors will "settle" and should be re-torqued 24 hours later.
That is 100 percent incorrect.
Did you watch the entire video? He goes on to explain why you only torque once. And backs it up with receipts.
First, that terminal block is made from aluminum, and not steel as you stated.
Second, if your skin effect argument was true, the ampacity of CCA would be higher than that of aluminum wire, but it is not (at least, at 60Hz), as the skin depth at normal utility frequency is far deeper than the thickness of the copper plating.
The ampacity of copper-clad aluminum IS greater than aluminum. That is not my opinion, that is a fact. When CCA is created it becomes a bimetal with different characteristics than copper or aluminum. The ampacity of the product lies between the two. The values in Table 310.16 are not going to be changed, however, because creating an ampacity table showing an ampacity table of 17A, for example, would be of no benefit.
soon they will add next changes as well for dipping some coating for copper strands for number 10 to 6 for subpanels and as well for ac disconnect switch..are we overdoing the safety..i am sure coating with wire goo would not rust the wires...but what cost doing so ?? its only 30AMPS to 60AMPS
What are you saying?
30A isn’t dangerous? I’ve seen house fires caused by 15A...
@@SuperVstech any amperage is dangerous for your heart...BUT NOT WITH SCREWS THAT GRAB THE WIRE TIGHT..TORQUE SPECS IS BS..i usually never over-tighten..longest i can tell the stranded wire is not wobbling at the screw lugs..you are good to go for installing breakers and final test of turning on the feeder breaker from main panel..JUST RELAX...everything is grounded correctly for both panels...1st pane,l I always check its bonded first before 2nd or 3rd panel are not..its right order and both detached from home and garage area/storage room have each ground rod...we are safe
@@user78405 wow... apparently you are an expert on wire contingency... code should just ask you for safety and consequences be damned...
torque specs aren’t there for grounding issues, or hear stopping faults...
It’s there to prevent fires.
Improper conductor securing can cause building fires.
You are actually seeing a lot of copper clad/Al in utility solar
Wait just a minute. Please explain the harm in tightening a connection too tight. That's absurd. Is there a requirement for yearly torque testing?
Damaging the conductor, damaging the damaging the terminal, damaging the equipment. No, there is no such requirement because the NEC ends at the installation [90.2(A)]. Maintenance is not within the scope. See NFPA 70B for recommended maintenance practices.
@@RyanJacksonElectrical lol
bolts stretch when they are over-tightened. they can also stretch somewhat when they're properly tightened, hence why there's a specific torque. an engineer figured the exact amount that bold should stretch to be as secure as it can be, without the risk of damaging the metal. if you keep making a bolt tighter and tighter, you get to a point where not only does it not tighten more, it'll start to fail and give way. most times in the world, good is good enough. but with electrical installation, much of the time you want that install to absolutely never fail. sometimes guessing with your own strength isn't good enough.
@@lorenzo42p I'm 60 years old and have been working in the repair field most of my adult life and even as a youngster growing up on a farm to a certain extent. I spent several years in related schooling. I'm very familiar with bolt stretch. I'm also very familiar with the fact that there's a difference in bolts. All that being said, it's really not realistic to think that screws in a 60hz ac system is only going to ever need tightened once. Not one time in my entire life have I had a connection fail because I didn't tighten it correctly. The only problem with connections is from a less than desirable tech and using a torque wrench isn't going to fix that. It will only hurt the ones that didn't need to use it in the first place.
@@engineclinic I want to prove you wrong,. But, I can't. There are estimates. Estimates don't prove much. However, there really isn't any other data, because in 1980, statistics weren't really that concise. I am a better safe than sorry type. The estimates are that there are currently half as many fires caused by electrical malfunction than there were in 1980, when you began. However, most electrical fires are NOT caused by poor quality in workmanship. In fact, it doesn't even rank in the top 7. Aging equipment, DIY repairs, turkeys, overloads, heaters, and extension cords all made the list. If I were to guess, if the 50% estimate were remotely true, it has very little to do with over or under torqueing connections. It probably has more to do with organizations like the NFPA creating awareness of the dangers of things like turkeys and tip switches on heaters. You can't educate the DIY'ers anymore than they choose to be, but I think that currently the DIY'er is a bit more savvy than they were 40 years ago. A lot of that has to do with the availability of information.
electricity doesn't flow mostly around the outside of a wire, that's mythical bull. that only applies to high frequency, which power lines are closer to dc than they are to a high frequency. the real reason you have diminishing returns on larger cables is the surface area, yes, but for different reasons. heat dissipation. that is also a reason why animals can't get much bigger than an elephant and why smaller animals have a much faster metabolism, surface area to get rid of waste heat. electricity flows for the most part evenly through the entire area of a cable. a down side of copper clad, it creates more heat internally, which needs more surface area to dissipate, which means a much bigger cable.
Yeah worry about terminations when your using push in connectors.
Crank it till it sqeeks not breaks👍
Goto any commercial construction site an find me electrician that has a calibrated torque wrench/screw driver. Then see if it looks used. Anyways love the idea but it’s only practical if you pay to have someone sign off on every panel during final install. (QA engineer) Most jobs can’t justify the cost.
You see it a lot more than did five years ago.
Ooof! Control panel wire...especially power wires, depending on the termination type(mechanically) depend soo much on strand count. A-B is the worst, IMO and ABB is the best. Nonetheless, course(low strand count) wires must be terminated with crimp lugs. Else, you could tighten them every hour and find that they are loose no matter the torque. VFD cable is good example. Low strand count is cheaper but demand crimp connectors plain and simple.
Hi Ryan can you please make more videos
Yes sir!
But only if you tell your friends. ;)
just for new wiring only new homes until adopted maybe in a yr for some locations
Alot issues to consider here Hitachi no login here squeal thinking that's too tight odds are the thread just broke cad aluminum and copper wire torque the same ? regardless the lug material the problem is the lug itself the manufactured should require a torque setting on the lug another thing to consider is does bolt or nut stretch , torque
It loosen it up and torque it again and yes moving wire round when it comes to bus duct bus bars 480 hanging bar system with removable buckets around the room most buckets were 30 to 60 amps the manufacturer required to be retighten every year and I would think that would go to the account of room temperature Four Seasons minimum maximum voltage draw vibration of the system we torque bolts about every two years and mark the bolts with different pin colors different years So when you say doing maintenance torque it one time and that's good enough leave regardless what that books reads ask yourself why don't Transformers come with lugs but they'll give you torque settings leave it up to the electrician to get you the bolts and nuts the washers and that great shit from the supply house from China which many lugs should have a torque setting and don't tell me to go to the manufacturer website and try to figure it out it all comes down to liability the Transformer , electrician , lug manufacturer, code book.,,,, how long is the warranty good for lol. Thanks for the discussion when you asked your inspector he reply why you asking me about proper torque settings ? He'll answer Don't put me in that situation lol
Hi this is canadien code
why so many changes now..?? ARE WE GUESSING AS WE GO RULES BY LEARNING FROM OUR MISTAKES AS WE GO THINGY ?? AM I TEST SUBJECT BY GREAT COUNCIL
code should be a guide, not end-all be-all. my opinion, and why I don't like "code". most people don't understand the reasons why code says to do it one way and not another. even in this video he got some things wrong.
Hate to be a noodge....It's Pounds Inch, I know Inch Pounds is commonly used, just like people often erroneously say Foot Pounds.....BUT,,,details matter, and you seem to be a detail guy, just a little bit,. Torque = force x distance, like Newton Meters....not Meters Newton.
“ properly calibrated “ haaa….Nothing should ever be assumed is obvious, when dealing with humans who are paid to hurry… are you kidding me.. that’s like saying it’s obvious we need to wear seatbelts , so who needs a rule to enforce it..
Codes are always changing just so the kids in school will have to buy new books and longer the length of time that one has to attend school to graduate.... take the test pass and get the patch... just like every other degree in colleges.... add more books add more time for the degree and of course add more dollars to attend...! then graduate....
There is are two problems with copper clad aluminium one, You may get charged for all copper (happens a lot) , measurement values go all to hell.
not a big deal to carry a torque wrench!
Apparently it is for the egocentric electricians who've been doing it wrong their entire careers