Thanks for sharing this. This is taking slow-blow fuses to a new level... never-blow. I have a box of no-name fuses too and will be getting rid of them.
Why not just test them first, at least the lower amperage ones? It's just... I too have such fuses and I know that they blew in my car at some point. 🤔 Sooo... My course of action would be to test the fuses that I can test with the equipment I have.
@@oilybrakes I can totally second that. I never got burned with cheap fuses. Some of them were a bit beyond their rating but i never got any that would never blow. Test 1-2 of each amperage and if they blow within spec, they're a keeper. Cheap isn't always bad and expensive isn't always good,
@@oilybrakes and only use the ones that blew when they should have ? Should I buy 5000 so I can take a sample large enough to get a good measure of tolerance and still have many left to use?
This is not the first time I have seen this style of demonstration. I was amazed at the data that the demonstration produced. Essentially the same outcome as your test, but lacking your sophistication. I was staying at a friends house several years ago, & I was given a spare room in their home to spend a night with them. This room was awaiting a contractor to tear out the ceiling & walls & install first grade insulation & such other work as he deemed necessary to make the room cozy in the coming winter. My friend had purchased an electric heater (1500 watts) & it was plugged into a wall socket that was a dedicated 20 amp circuit. About an hour after retiring I awoke because of an odd smell. I sat up in bed & the electrical heater was engulfed in flames, & the power cord was burning along its length. One door in the room opened into the house proper, & the other opened into the back yard. I had left my jacket , trousers & outside boots beside the bed . I turned on the night table lamp, pulled my boots on & grabbed my coat & removed my leather gloves(work style, not "dressy" style), grabbed the handle of the heater (which was already starting to melt) , opened the outside door & heaved the heater into the yard, & then turned & pulled the power cord from the wall socket, & threw it into the yard. The rug was on fire, but it was a material that was very slow burning ( treated as "fire retardant"" & it joined the rest of the immolation in the yard. The next door neighbor saw the flames & ran into the back yard with a CO2 extinguisher & snuffed the burning bits out. My friend ran 9into the rook & did the same to the rug & we opened the two windows in the room to lose the smoke. Another neighbor had summoned the fire dept. & they & the police arrived together. The Captain declared the fire officially out (a second co2 bottle was used & they made certain the flooring beneath the rug & the wire & wood behind the melted outlet was flame free. The fire Captain said that the Provincial Fire Marshall's office was attempting to have that particular heater banned from sale. The next day we bought a new 20 amp duplex receptacle, & I installed it . The lady of the house plugged a floor lamp into it, & turned the light on & all appeared well. I went to close the door on the entrance panel , & noticed that the dedicated breaker was open, but the light was still on ! I reset the breaker, & it was not latching. I removed the floor plate on the breaker board & removed the 20 amp breaker & took it apart, to find the contacts were welded shut !! My friend asked me what I thought. I told him that I thought that he should call a Provincially licensed contractor & have him examine the panel installation, & anything else he deemed necessary, & to give you a report. The panel was made in China, & all its internals were as well. Most of the wiring had to be changed as well. My friend engaged his insurance company at this point, because his sister from whom he had purchased the house & who had paid a local electrical contractor to upgrade the house from a 60 amp circuit to a two hundred amp service, & it ALL had to be removed & approved equipment installed at great expense. You never know these days.
I go to a generally recognized national auto parts store for my fuses (I generally use Bussman). The price difference between the better fuses and the generic ones is pretty minimal compared to the value the better ones provide, in the larger picture. Nice video.
just this week I had smoke come out from under the dashboard of my car , 2 wires dead shorted and went red hot , burnt all the outer covering to a crisp , they where supposed to be protected by a 10 amp fuse , all that the fuse did was melt a little bit , but did not blow. I think the cars battery is a 60 amp. I will be replacing all the cheap fuses with brand names asap. thanks for your video.
Discovered the same thing about 10-12 years ago when a cheap fuse from one of those kits failed to blow when a wire shorted to ground on a motorcycle. The end result was a small fire and many hours of labor replacing the bike's wiring harness. I contacted the seller and let them know what happened; they didn't believe me. Testing the fuses found the same thing as in this video, they just didn't open under 2x-3x their rated load.
Just shocking. Never thought the China fuses were that far off , it’s simply so dangerous that the companies that put them up for sale should be sued. Thanks for an interesting test.
I saw a doctor in china comparing medical thermometers. They were all showing different readings. China is simply too corrupt to produce quality products.
Thank you for doing this and sharing it. I have for years used any old fuse I could find (correct stated rating though). I will avoid noname fuses from here on out! Shocking results.
Thank you very, very much for this video. As a motorhome owner this is very worrying as I have been using those cheap fuses for years. I have been very lucky. I am buying a set of decent ones straight away and replacing them all. Thanks again.
... some months ago i had my fuse box melt down while i was driving, and i had no idea how the heck it happened. looks like i might have just found out.. ty so much, i am gonna go grab some bussmann resettables and pray they're authentic i think XD
Thanks for a great informative video. I threw out the chinesium 100 pack fuse assortment I bought over the summer after watching this video and bought Littel and Bussman fuses for my ham equipment. 73 de KH6DC
I ditched the cheap fuses not over the (unknown to me) failure to blow, but rather over their inconsistent thickness and inability to reliably make contact with sockets. Many off brand fuses are some random pot metal that doesn't seem to fit correctly, and have all sorts of strange geometry on the legs that you push into the sockets, compared to the Bussman, LittleFuse, and other OEM fuses that all fit snugly and have well formed connection legs.
One thing you'll also find with the cheap generic no noame fuses is the blade material is thinner, therefore it doesn't have the same contact pressure and that allows resistance and heat build up. I've seen a few of thses melt in the past. I'd also check the temperature of the powerpole connectors as they are rubbish, I refuse to use them. Very disconcerting that the 5A fuse just doesn't blow at 20A though, so generally zero protection and 100% dangerous.
Thanks for a superb video and useful warning. I'm a glider pilot and use this type of fuse to protect the wiring that runs under my seat; I can't remember where I bought them. I must figure out how to control the current from a lead-acid battery so I can check one or two of mine!
Fuse wire is made from a special metal alloy wire that will fuse(When any wire melts open, it is said to fuse) that is suspended between the mounting connections hence the added value.The giant bag of fuses for a dollar that I have inspected seem like the fuse wire in them is just part of the stamped out aluminium mounting blades hence no value. Great video N0̷PXJ
I discovered this a while ago, After having to re wire the loom on a friends Quadbike, I tested the 45A at 60A and it melted the plastic but didn't blow. Lawson Fuses are the best.
Thanks for the chart, one more data point, typically those chinese fuses are aluminum, and aluminum on standard tinned brass terminals is a corrosion and fire hazard when exposed to wet environments. I had a piece of outdoor equipment, 30a fuse for the glow plugs ended up burning up the whole fuse block. clipping one fuse leg will show if its tinned brass or aluminum. Buss fuses are a guarantee to be tinned brass
The fuses that are hard to read, don't have the rating colored white, are the ones that are not "certified " as I understand. I found a video similar to yours stating this. I trashed my assortment from Harbor Freight, and purchased a Littelfuse assortment. Great video
Some major brand in the UK, Halfords, doesn't state that they match the DIN standard, not any set of qualities with reference to it. I've no idea whether they blow as fast as they should, nor as close to the rating as they should, and they didn't promise that they would either.
I have several of these boxes and DID get an expected clear on fuses below 5amps. I need to test them and also would have liked to see you text the bigger no names. Guess I need to price out name brand on fuses boxes and test my cheapies
This is a great bit of advice, and a nice catch. I can only imagine how many of these no-name kits have been sold, and how many devices out there are virtually unprotected due to the use of imposter fuses! As another viewer commented, some of the dirt-cheap fuses are made with some rather dubious metals that rust/corrode, and that's a deal-breaker in and of itself! I'm not in the radio field, my interests lean more towards automotive and computers, but I've always used Littelfuse or Bussmann - leaning more towards Bussmann as the fuse bodies are more translucent and easier to see gaps. I feel more comfortable with a brand I've used for years, over some brand I've never heard of that has so many vowels that I'm not exactly sure how to pronounce it. The price differential isn't significant enough for me to "go cheap." Sometimes you really do get what you pay for! When I first saw the 5-Amp in your test rig on the bench, my initial thought was "that link is WAAYYY too thick to be a fiver..." At a glance, it looks like a 20-Amp or 25-Amp. I know what some of you are probably shouting at your screen right now: "you can't properly rate a fuse based on looks alone," and generally speaking, yes, you're absolutely right and I wholeheartedly agree. BUT this fuse was CLEARLY not a 5-Amp, heck, it's more like a fuse-shaped link! As you so handily demonstrated, it could easily withstand multiple long-run tests at 400% rated current. I've seen heat-warped fuse blocks once in a while, in cars that I've repaired over the years. I think you might have solved the mystery for how that happens - OEM fuses pop and some "El Cheapo" fuses the owner bought shoved in to replace them. I watch a few HVACR channels, and most RTU (rooftop units) use a 5-Amp blade fuse to protect the control boards. I might drop a note with those Creators and suggest they buy Bussmann or Littelfuse exclusively. I assume they do, since they go through commercial warehouses, but they've got businesses to run and might consider trimming overhead by buying bulk no-names.
great video and a solid reminder to ALWAYS buy name brand fuses that specifically list the specs and have the UL seal of approval. Remember... you get what you pay for.
A certain company named after a major feature in South America is notorious for selling electrical devices of all sorts that don't carry any credible safety agency approval/certifications. I think a lot of this stuff comes from companies that say "yes, we can make that" when what they really mean is "we can make something that looks like that." I did once see a small wooden model that was claimed to be FCC certified. Now I am willing to admit that a chunk of wood is quite unlikely to generate EMI or RFI, but ...
I bought a similar pack of bargain fuses, and had some suspicion, based on the thickness of the internal conductor, that their rating was off. You just verified what I suspected, in a rather dramatic and more accurate fashion. Thanks!
I have some no name fuses and no longer use them. One was melting, turning black, smoking, and almost caught fire after running at capacity for a long period of time.
About that fire extinguisher - you might want to get one with metal handles. I've heard stories about the plastic ones breaking during test. (Especially if you fail to properly remove the safety.) They're a little more expensive and a bit bigger, but still a good investment.
@@HamRadioA2Z Another tip: Get CO2 extinguishers for dealing with equipment fires. The other types will make a mess of things and potentially create a bigger problem as the electrical fire heats things up.
@@russellhltn1396 I usually reccommend Foam extinguishers. Sligthly less effective than powder, but doesn't destroy everything that the fire didn't damage.
@@HamRadioA2Z Have you ever seen the mess created by a dry powder fire extinguisher, especially in a relatively confined space? What makes matters worse..the powder is hydroscopic, and will corrode metals if you don't vacuum every last trace.
In the UK, I have found those "cheap and nasty" fuses have blades made of aluminum 0.5mm thick. The decent fuses have blades made of nickel plated brass, 0.7mm thick. So there is potential for the cheap fuses to give a bad contact. I once made sure I gave eveyone in my car club a "free fuse" and told them that if you can easily bend the blades like you can on your free gift, don't buy it...
Brass is a pretty dismal conductor of heat, whereas aluminum is as good as it gets, excluding copper and silver. Since fuses are really just self-heating resistors that melt themselves to oblivion, removing heat "too fast" will delay or even prevent blowing.
@@raymiller5738 That's why aluminum has been largely banned for AC mains wiring - joints tended to be unreliable and cause fires. There are problems with both oxidation (aluminum oxide is an excellent insulator) and "cold flow." I have a small single-AA cell, single mode flashlight I really like except for one problem - the tail cap of case was notorious for going high-resistance between the cap and body threads. A tiny bit of a zinc paste (Gardner Bender OX-100B), intended for use on aluminum wires, on the threads fixed the problem nicely.
Great job! Sometimes a return to basic component information is invaluable. I think another component that needs examination is clone Anderson Power Points. Many of them look right, but do not use the proper materials and arc at very low currents! Hope you'll do more things like this....
I was scrapping a Fiat and cut a wire of the fuel injection on accident. The fuse of the fuel injection melted it's casing and later the entire socket but did not blow . The wires started burning first. It was an original fuse
A very good demonstration and an eye-opener to modern day equipment. I have very little new equipment as I am a homebrewer and operate boat-anchor vacuum tube equipment. The fact that the voltage on the power supply drops to 0.6 volts and still maintains 20A is amazing to me. That is 12 watts of heat being dissipated in the fuse, as your temperature measurements indicated, which seems like it would melt the fuse link in a reasonably short time. Apparently not... My power supplies are all the linear brute-force type and shorting one of them will likely not drop the voltage any significant amount so we would end up with the full 15 volts (as in your example) at 20A for 300 watts being dissipated in the fuse and we all know where that is going to go and hopefully the fuse will protect the equipment from catastrophic damage and possible fire. With over-current sensing in SMPS in modern equipment, it almost seems redundant to put a fuse in the output side, although I think it is still a good idea. 73 WA4QGA
I'm most impressed! Very important info. Now I got to go check my fuses. Don't forget to check what goes in your car, lots of sensitive stuff in there.
This topic was covered a year or more ago, with comparison tests as well. ALL the colors of blade fuses from parts unknown would hold 40 AMPS ... be they molded as a 5, 10, 20, 30 OR 40. A USED CAR LIKELY HAS SOME OF THESE. The hazard is from putting in a no-blo fuse into a bad circuit that popped the GOOD ( blown ) fuse, without diagnosing and repairing the vehicle. Expect to ruin a wire harness or worse.
Hi, Tom. Thanks for the very informative and interesting video. Blade fuses are a type of commodity item I've never really thought twice about. I guess not all of them "just work". I'd hate to have one of those 5A no-name fuses "protecting" a sensitive circuit in my vehicle. Well done. Marc (N1QGM)
Pay attention. Any fuse like these, no matter what manufacturer, will NOT protect 'sensitive' equipment. They are only intended to protect wiring systems.
I had some of these no name ones in our Peterbilt fuse panels until we found out some of them would actually catch the plastic on the fuse on fire and still not blow the fuse! Never again.
This comes as no surprise to me, Chinese manufacturering often times substitutes for materials that are not in stock or considered too costly in their opinion. They probably substituted aluminum wire for the tin or indium fuse element. One clue is the DC resistance, it is most likely abnormally low. I discovered similar problems with the Chinese marine style thermal circuit breakers 3 years ago. These trip at 1/3rd to 1/10th the stated current. They can also chatter when they are about to trip. I finally had to test each breaker for it's trip point, then label the breakers accordingly.
There was a massive recall of these fuses a few years ago, because the only difference between the fuses was the colour of the body, as they all used the same stamped out fuse element, and simply put a different colour body on the top. Millions of boxes recalled, they had to go somewhere, so likely got sold off as lots cheap. Basically look at the elements, if they are all the same size they are all 30A fuses.
Extremely helpful video! I've got a package of Bussman fuses on order and am going to swap out all my current no-name blades as soon as it arrives. Never thought about fuses before and just assumed a fuse is a fuse is a fuse. Thank you so much for this informative video! 73!
I had some of these fuses around and used them once for some relays, a fan they were controlling got jammed and it should have blown the fuse but instead melted all the plastic off of the fuse and got everything pretty hot. I bought a box of legitimate brand fuses and made sure that I never used the cheap ones again.
Great video! Excellent warning about cheap fuses that often get taken for granted. Please note though, that those types of heat guns observe a rather large conical region in front of them to determine the temp. They do NOT measure the point at the red laser dot. Unless one is measuring a larger area (like a frying pan for example), they are inaccurate for small spot measurements like the fuse - the fuse is likely to be much hotter than one it displays since it is averaging same of the desktop temp with the fuse. Nonetheless, awesome video. Will be sharing this with others!
I have considered doing a video about breakers. Even good quality circuit breakers take longer to trip than a fuse because of the nature of how they operate. As I said at the beginning of the video, fuses and circuit breakers are primarily designed to protect wiring from catching fire. They’re not really designed to protect our electronic equipment from internal faults.
@@HamRadioA2Z You might also want to look at DC breakers. Some of the polarized ones actually interrupt the arc faster when connected in reverse. I get all this stuff free from manufacturers. Sure glad I'm not having top for some of these products. It is the wild west on these CE listed products!
There's over 12w dissipated in your setup with the Chinese 5a fuse, yet the temperature rise after a couple of minutes is less than 70deg C. Metals and alloys are not likely to melt at this temperature. It most likely that they are using copper or some very conductive material in the fuse, instead of the right alloy. The power from the supply is being evenly dissipated in the cables and fuse instead of the fuse heating significantly more than the cables.
Thanks for taking the time to share this information! Before throwing them out, maybe test them on a car battery in various parallel configurations. Then maybe you can repurpose the 5A fuses to protect 00 wire...😛
I was randomly recommended this video and straight up bought spare bussman fuses (the littelfuse kits were about the same price) just now. Glad I never had to use the spares I bought a couple years ago, those will go straight to the trash. It seems like the knockoff kits spent all of their money on a case so maybe I'll put the good bussman fuses in that. Thanks!
For 44 years, I taught aircraft electrical/avionics/weapons control systems maintenance. I do not remember one new student knowing the true purpose of fuses/circuit breakers. When we got done, they knew.
Had always assumed a fuse was a fuse, and even though I have a couple kits of brand-name fuses, I also have probably that exact same kit of generic fuses. Throwing it out. Thanks!
Excellent video, thanx for the warning. I did buy a non-branded kit "ABN". Tested the kit on my PSU and the fuses up to 20A cleared in a timely manner. Looks like the fuses you had were just bits of wire between the lugs... Thanks again.
Thank you for this video! I had cheap fuses laying around and tested them, this is what i found: 1. 3A fuses did not blow at 10 amps even after 3 minutes 2. My switching-mode power supply blew a couple of 2A fuses at
Thank you for your excellent review. I also purchase a box of 300 no name blade fuses from EBay for $16 and had quite a different experience. I replace the original 30 Amp fuse with one from 30 Amp fuse from EBay that is in line with a solar regulator. The solar regulator runs a maximum of 25 amps and the plastic that encapsulated the blade fuse wire melted exposing the fuse wire. It seems that they made of a plastic with a very low melting point. I wonder if the current did get to 30 Amps or above 30 Amps that it would catch on fire.
Thanks for sharing this. I always say that government has a function. One of those functions is to protect consumers. When safety devices fail to do their job, the government should prohibit their sale as a risk to safety. My only concern with your test is you showed only one test of a 5 amp fuse. I'd like to see the results of 5-5 amp, 5-10 amp, and 5 -15 amp fuses. Certifications are important. But even without them any safety device should perform as expected or be prohibited from sale.
The best thing about the no name fuses are the cases, and they often come with pullers. So toss the fuses out but keep the case, and then put in brand name fuses. A lot less finicky to open than the Littelfuse or Bussmann cases, for sure.
UK mains plug fuses come in 3 and 13 amps mostly. 1,2,5,7,10 amp also. They look like 1 and1/4 inch ceramic fuses except 1 inch. A UK kettle often uses the full 13 amps ( 12.67A 240V mine ). This is often Bushmann fuses and relaible or years. These fuses were a way to reduce copper used in wartime circa 1943. It actually reduce impedance as it's a ring circuit. It also protects the power cord. The fuses are 15 cents. The ring is 32 amps. 6 amps lights on a radial. 100 amps typical company fuse. I once installed a 6.3AT 20mm fuse on a10 amps kettle at the factory. The staff knew. Months later it still worked. It was high grade. The graphs sort of said it could. Although I didn't ask 1 minute could be the cycle time for a mug or two of tea ( 50 a day ? ). This was to test a real application.
I've been seeing some strange failure modes with older H-type ribbon Buss glass fuses. The fuse blows in the center, deposition coats the glass, and the remaining ribbon ends sag and reestablish a resistive contact. The circuit looks like the right voltage is there, but can carry no major current. Twice in 2 years.
I actually ran into this myself doing load testing for sizing the fuse for an electronics project - I use pico fuses which are about the size of a grain of rice. The Amazon ones listed for 500mA fast blow didn't blow until over 1.5A. Some knock-off Littelfuse ones I found on there too, rated for 2A Fast Blow, didn't blow until they had almost 250% over their rating (4.5A), and that was ratcheting up the current quickly. I got on Digikey and got genuine Littlefuse pico fuses, and they all blow at almost EXACTLY their specified current. It's almost like these Chinese companies just stamp out fuses from any pot metal they can find and then injection mold it. It's truly scary if you think about it.
Nice video. And also a very important topic. These cheap "dummy-fuses" won#t save you a penny, if your car or even your house catches fire and burns to ashes. But, just for showing the seriousness of the danger (and for fun), you should have used thinner wire, that actually melts or lights up. Anyway, amazing video, thank you. 73s
I wanted to blow a no-name 15A blade fuse recently and tried to use a car battery to do it. It isn't a handheld project, I found out. I didn't think hard enough, that maybe the cheap fuse was the problem.
Thanks for the tests. Just 2 comments, it could be sped up only, mentioned twice sloowly the ebay amazon (we got it the first time around! ;)). Second thing the mic scratching can be painful after a while. I hope it will help make your next viseo even better!
I was reminded long long long ago that my auto instructor said you're paying for the metal they use for these fuses, & they were coming from a place of experience.
You have illustrated overcurrent protection in the precise way it is intended to work. The startling issue I had not expected is the lack of specification on the chinesium fuses. Very nicely done and an important warning.TNX
I just tore down one of these fuses, the fuse is made out of aluminum, to get a fuse to blow the wire has to be a specific diameter. Each fuse is cut from a flat plate of aluminum, probably in a stamping machine. The theory is that the machine stamps the wire accurately to a specific size. My guess is that the metal isn't the right material (they just used a piece of ordinary metal) and/or the stamping machine is highly inaccurate.
They are all stamped to be 30A fuses, just the colour and embossed amps is different. Done to reduce cost, as the 30A unit is the most robust, and cheap to make, and then you just put the cover on to make the others. They were recalled as defective years ago, but are still sold cheap in kits, because there is no QC done on them at all. If you see a box compare the fuse element between the ratings, they are all the same size, while real ones the fuse gets thinner as you go down, or it is a thin wire spot welded or crimped between the blades on the lowest current ones.
Wow! You're right, thanks for testing these. I have a box of no name fuses also, I just tested several 5 amp fuses on a quality 20 amp power supply - they didn't blow, I even tested the ten amp fuses.
Wow! I'm not a radio guy but really appreciate YT for suggesting this video. I recently bought one of those cheap fuse kits on Amazon to keep in my RV. Not only will I toss that kit out but I'm going to have to go through all the fuses in my coach because I've a bad feeling that the manufacturer of my RV may have used these cheap fuses. I can only wonder how many camper fires might have been caused by one of these poorly made fuses. Thanks!!!
Very good illustration. I look forward to seeing the crowbar device. I’ve always been mystified that little premade in-line crowbar devices aren’t on the market. I’d love to see some adjustable ones that could be used on 13.8 or even 5v applications. I tend to tinker with power supplies and have modified some to have remote sensing, but I’m always worried that something will go wrong and the devices being powered could see high voltages if the sensing wire ever became disconnected.
If the supply lines are big enough to handle the current, there isn't any need for sense lines, unless you have some very fussy equipment, but even then, increase the diameter of the supply lines to meet the demand without excess Voltage drop.
I'd of never thought that no name fuses would be THAT bad! I think I have some and will check them and probably through them out. Thanks for making this video. I too am a Ham Radio guy.
To just test fuses you can make one of these 2 cheap and easy solutions: Microwave transformer converted to high current transformer, and adjust the primary input with a variac/autotransformer, Or use a car battery and have some adjustable load, like a combination of big resistors, a diy basic transistor load, a chunky dc motor and braking progressively, or something else that you already have at hand. To measure current, a current clamp would be the best option for this kind of high currents.
I tested the set that I have, and the fuses are operating correctly. They blow in 1s at 2x rated current. The only slight issue that I don't know if it's normal or not, at 1.3x current they glow red and melt the plastic a bit but they do eventually blow. The set is Herbert Müllner BOX-AS147. They are visually similar to yours with the embossed current rating that's hard to read but have a different fusing element. So it's not possible to distinguish good from bad just visually.
Great video Tom! Maybe you can repurpose the fuses into current shunts for amp meters. I usually use buss man or little fuse. Another problem I have found with the cheap ones in oxidation. They build up and become resistive dropping the overall power. 73
Great video.. I was just mentioning to my brother a few days ago not to buy no-name fuses and to stick bussmann, etc. For individual fuses, I usually purchase them from digikey or mouser to be safe.
get the oscilloscope to measure across a high current shunt and use a car battery across the fuse to blow it up. the shunt will measure the time + peak current require to blow the cheap vs branded ones. and i always use little fuse. , i keep a box of their energy kit in my car although i have never needed it. but i do use blade fuses everywhere. they are easy to replace and works fine for low voltage dc.
@@stargazer7644 that would be a realistic test because these are connected directly to a car battery that can deliver 600amps under near short circuit. So if a module or accessories goes short then you also need to know the peak current and the time it takes for the fuse to blow. Because a storage oscilloscope can time it down to nano seconds.
@@KuntalGhosh A fuse is not designed to limit current before it blows. I've never needed to know those numbers when designing a circuit. You simply use the fuse that is rated for the job.
@@KuntalGhoshA realistic test would be to connect the 5 amp fuse to the battery using 10 feet of 20 AWG wire. The resistance of the wire would be about 0.1 ohm. The resistance of the fuse in the test is about 0.025 ohm. The current would be about 100 amps. The fake fuse might blow before the wire was cooked, but I wouldn't count on it.
I had that cheap chinese fuse kit. After seeing your video 2 months ago i threw them all out and bought all Bussman. I did use the chinese plastic case.
I remember a 528e back when German cars use ceramic/thermosetting strip fuses . Red 16 white 8blue25. It was burned out in the roof from a dome light short. The fuse was replaced from white to blue.
WOW, that's unbelievable. I had no idea. I won't be buying those on Amazon. I wonder how accurate the auto reset blade circuit breakers are. I have a friend who has a box truck he uses for work. It has an intermittent short on a 15 amp light circuit. Sometimes it will go for weeks without blowing the fuse. I couldn't find the problem. I was thinking about mentioning the circuit breaker so his lights would come back on at night. Would you want to test those breakers?
Totally agree. Unfortunately it's really hard in the UK to find any parts like this that aren't cheap C...ese crap. Britain used to make all these kinds of things, but all those companies have long since closed down. I searched for ages and still couldn't find any quality fuses.
Wow, so dangerous thanks for the video glad I only have standard height mini fuses that are no name. And my low profile ones are Bussman. Will be getting new fuses for digging into my families vehicles for the nonpainted no brand fuses
Thanks for doing this experiment! Would you repeat it without that bench power supply, and use a car battery instead? The current and voltage at the fuse under test could be measured with a two channel oscilloscope (one channel connected to a suitable current shunt) 73, de K7GVG
And add a contactor rated a few hundred amps, so it can be done out in the yard/driveway and switched on or off from a safe distance in case the wires blow first.
Thanks for sharing this. This is taking slow-blow fuses to a new level... never-blow. I have a box of no-name fuses too and will be getting rid of them.
Why not just test them first, at least the lower amperage ones?
It's just... I too have such fuses and I know that they blew in my car at some point. 🤔
Sooo... My course of action would be to test the fuses that I can test with the equipment I have.
@@oilybrakes I can totally second that. I never got burned with cheap fuses. Some of them were a bit beyond their rating but i never got any that would never blow. Test 1-2 of each amperage and if they blow within spec, they're a keeper. Cheap isn't always bad and expensive isn't always good,
@@oilybrakes and only use the ones that blew when they should have ? Should I buy 5000 so I can take a sample large enough to get a good measure of tolerance and still have many left to use?
@@tricky778 Once you tested them, you will know that they are in spec. What else do you want?
@@oilybrakes once I know they're on spec they will not conduct. I want them to conduct.
Glad you did this test. I had always assumed off brand fuses woukd be at least close to thier rating. Thank you.
This is not the first time I have seen this style of demonstration. I was amazed at the data that the demonstration produced. Essentially the same outcome as your test, but lacking your sophistication.
I was staying at a friends house several years ago, & I was given a spare room in their home to spend a night with them. This room was awaiting a contractor to tear out the ceiling & walls & install first grade insulation & such other work as he deemed necessary to make the room cozy in the coming winter.
My friend had purchased an electric heater (1500 watts) & it was plugged into a wall socket that was a dedicated 20 amp circuit. About an hour after retiring I awoke because of an odd smell. I sat up in bed & the electrical heater was engulfed in flames, & the power cord was burning along its length. One door in the room opened into the house proper, & the other opened into the back yard. I had left my jacket , trousers & outside boots beside the bed . I turned on the night table lamp, pulled my boots on & grabbed my coat & removed my leather gloves(work style, not "dressy" style), grabbed the handle of the heater (which was already starting to melt) , opened the outside door & heaved the heater into the yard, & then turned & pulled the power cord from the wall socket, & threw it into the yard. The rug was on fire, but it was a material that was very slow burning ( treated as "fire retardant"" & it joined the rest of the immolation in the yard. The next door neighbor saw the flames & ran into the back yard with a CO2 extinguisher & snuffed the burning bits out. My friend ran 9into the rook & did the same to the rug & we opened the two windows in the room to lose the smoke. Another neighbor had summoned the fire dept. & they & the police arrived together. The Captain declared the fire officially out (a second co2 bottle was used & they made certain the flooring beneath the rug & the wire & wood behind the melted outlet was
flame free. The fire Captain said that the Provincial Fire Marshall's office was attempting to have that particular heater banned from sale. The next day we bought a new 20 amp duplex receptacle, & I installed it . The lady of the house plugged a floor lamp into it, & turned the light on & all appeared well. I went to close the door on the entrance panel , & noticed that the dedicated breaker was open, but the light was still on ! I reset the breaker, & it was not latching. I removed the floor plate on the breaker board & removed the 20 amp breaker & took it apart, to find the contacts were welded shut !! My friend asked me what I thought. I told him that I thought that he should call a Provincially licensed contractor & have him
examine the panel installation, & anything else he deemed necessary, & to give you a report. The panel was made in China, & all its internals were as well. Most of the wiring had to be changed as well. My friend engaged his insurance company at this point, because his sister from whom he had purchased the house & who had paid a local electrical contractor to upgrade the house from a 60 amp circuit to a two hundred amp service, & it ALL had to be removed & approved equipment installed at great expense.
You never know these days.
I go to a generally recognized national auto parts store for my fuses (I generally use Bussman). The price difference between the better fuses and the generic ones is pretty minimal compared to the value the better ones provide, in the larger picture. Nice video.
Yikes!
Talk about “penny wise, pound foolish.” It’s never occurred to me that I might be using no-blo fuses. Time to do some testing!
The ones to watch out for the most are cheap no name fuses made in China. Chinese manufacturers are known for not making things within spec.
I'm building a van and you just scared the crap out of me!!! I just order 2 big boxes of Littlefuse blades.
Thank you so much.
just this week I had smoke come out from under the dashboard of my car , 2 wires dead shorted and went red hot , burnt all the outer covering to a crisp , they where supposed to be protected by a 10 amp fuse , all that the fuse did was melt a little bit , but did not blow. I think the cars battery is a 60 amp. I will be replacing all the cheap fuses with brand names asap. thanks for your video.
Those fuses are nothing more than pretty plastic covered nails.
I suspect they're all the same, that's why spent the extra resources on the different colors
@@Eduardo_EspinozaThey certainly look it from the pics, all the wires look the same thickness
Discovered the same thing about 10-12 years ago when a cheap fuse from one of those kits failed to blow when a wire shorted to ground on a motorcycle. The end result was a small fire and many hours of labor replacing the bike's wiring harness. I contacted the seller and let them know what happened; they didn't believe me.
Testing the fuses found the same thing as in this video, they just didn't open under 2x-3x their rated load.
All this must be due to a Chinese translation problem. Where in English said fuse it corresponded to the Chinese for "heating element" 😊
Just shocking. Never thought the China fuses were that far off , it’s simply so dangerous that the companies that put them up for sale should be sued. Thanks for an interesting test.
I saw a doctor in china comparing medical thermometers. They were all showing different readings. China is simply too corrupt to produce quality products.
How ? are you going to sue Brandon
ESPECIALLY BRANDON!!!!
Thank you for doing this and sharing it. I have for years used any old fuse I could find (correct stated rating though). I will avoid noname fuses from here on out! Shocking results.
Thanks for the eye opening information. I've always used Littlefuse and Bussman fuses whenever possible, but now I'll stay with them all the time.
Thank you very, very much for this video. As a motorhome owner this is very worrying as I have been using those cheap fuses for years. I have been very lucky.
I am buying a set of decent ones straight away and replacing them all. Thanks again.
Thanks for the heads up on these fuses. I have a bunch of these fuses in a box and a few in service. I will now toss all of them.
... some months ago i had my fuse box melt down while i was driving, and i had no idea how the heck it happened.
looks like i might have just found out.. ty so much, i am gonna go grab some bussmann resettables and pray they're authentic i think XD
Very interesting
I'm a mechanic and I didn't know that all fuses were not created equal
I will no longer be buying cheap fuses
Thank you
Thanks for a great informative video. I threw out the chinesium 100 pack fuse assortment I bought over the summer after watching this video and bought Littel and Bussman fuses for my ham equipment. 73 de KH6DC
I ditched the cheap fuses not over the (unknown to me) failure to blow, but rather over their inconsistent thickness and inability to reliably make contact with sockets.
Many off brand fuses are some random pot metal that doesn't seem to fit correctly, and have all sorts of strange geometry on the legs that you push into the sockets, compared to the Bussman, LittleFuse, and other OEM fuses that all fit snugly and have well formed connection legs.
One thing you'll also find with the cheap generic no noame fuses is the blade material is thinner, therefore it doesn't have the same contact pressure and that allows resistance and heat build up. I've seen a few of thses melt in the past. I'd also check the temperature of the powerpole connectors as they are rubbish, I refuse to use them. Very disconcerting that the 5A fuse just doesn't blow at 20A though, so generally zero protection and 100% dangerous.
Could you please explain further what is bad about power pole connectors?
Those no-name fuses can come in handy since it would be difficult to get a penny in that blade fuse holder.
Thanks for a superb video and useful warning. I'm a glider pilot and use this type of fuse to protect the wiring that runs under my seat; I can't remember where I bought them. I must figure out how to control the current from a lead-acid battery so I can check one or two of mine!
Fuse wire is made from a special metal alloy wire that will fuse(When any wire melts open, it is said to fuse) that is suspended between the mounting connections hence the added value.The giant bag of fuses for a dollar that I have inspected seem like the fuse wire in them is just part of the stamped out aluminium mounting blades hence no value. Great video N0̷PXJ
These fuses are the best kind! All the other ones blow out so fast! This is the last fuse you will ever need to buy.
I discovered this a while ago, After having to re wire the loom on a friends Quadbike, I tested the 45A at 60A and it melted the plastic but didn't blow. Lawson Fuses are the best.
Thanks for the chart, one more data point, typically those chinese fuses are aluminum, and aluminum on standard tinned brass terminals is a corrosion and fire hazard when exposed to wet environments. I had a piece of outdoor equipment, 30a fuse for the glow plugs ended up burning up the whole fuse block. clipping one fuse leg will show if its tinned brass or aluminum. Buss fuses are a guarantee to be tinned brass
The fuses that are hard to read, don't have the rating colored white, are the ones that are not "certified " as I understand. I found a video similar to yours stating this. I trashed my assortment from Harbor Freight, and purchased a Littelfuse assortment. Great video
I have oem ones that don't have that
Some major brand in the UK, Halfords, doesn't state that they match the DIN standard, not any set of qualities with reference to it. I've no idea whether they blow as fast as they should, nor as close to the rating as they should, and they didn't promise that they would either.
This information is soo needed.
This was 101 in my day.
Trust but verify… especially when expensive equipment is involved.
I have several of these boxes and DID get an expected clear on fuses below 5amps. I need to test them and also would have liked to see you text the bigger no names. Guess I need to price out name brand on fuses boxes and test my cheapies
This is a great bit of advice, and a nice catch. I can only imagine how many of these no-name kits have been sold, and how many devices out there are virtually unprotected due to the use of imposter fuses! As another viewer commented, some of the dirt-cheap fuses are made with some rather dubious metals that rust/corrode, and that's a deal-breaker in and of itself!
I'm not in the radio field, my interests lean more towards automotive and computers, but I've always used Littelfuse or Bussmann - leaning more towards Bussmann as the fuse bodies are more translucent and easier to see gaps. I feel more comfortable with a brand I've used for years, over some brand I've never heard of that has so many vowels that I'm not exactly sure how to pronounce it. The price differential isn't significant enough for me to "go cheap." Sometimes you really do get what you pay for!
When I first saw the 5-Amp in your test rig on the bench, my initial thought was "that link is WAAYYY too thick to be a fiver..." At a glance, it looks like a 20-Amp or 25-Amp. I know what some of you are probably shouting at your screen right now: "you can't properly rate a fuse based on looks alone," and generally speaking, yes, you're absolutely right and I wholeheartedly agree. BUT this fuse was CLEARLY not a 5-Amp, heck, it's more like a fuse-shaped link! As you so handily demonstrated, it could easily withstand multiple long-run tests at 400% rated current. I've seen heat-warped fuse blocks once in a while, in cars that I've repaired over the years. I think you might have solved the mystery for how that happens - OEM fuses pop and some "El Cheapo" fuses the owner bought shoved in to replace them.
I watch a few HVACR channels, and most RTU (rooftop units) use a 5-Amp blade fuse to protect the control boards. I might drop a note with those Creators and suggest they buy Bussmann or Littelfuse exclusively. I assume they do, since they go through commercial warehouses, but they've got businesses to run and might consider trimming overhead by buying bulk no-names.
great video and a solid reminder to ALWAYS buy name brand fuses that specifically list the specs and have the UL seal of approval. Remember... you get what you pay for.
A certain company named after a major feature in South America is notorious for selling electrical devices of all sorts that don't carry any credible safety agency approval/certifications.
I think a lot of this stuff comes from companies that say "yes, we can make that" when what they really mean is "we can make something that looks like that."
I did once see a small wooden model that was claimed to be FCC certified. Now I am willing to admit that a chunk of wood is quite unlikely to generate EMI or RFI, but ...
I bought a similar pack of bargain fuses, and had some suspicion, based on the thickness of the internal conductor, that their rating was off. You just verified what I suspected, in a rather dramatic and more accurate fashion. Thanks!
This is why you don't cheap out on fuses, circuit breakers , cables or connectors and lugs
I have some no name fuses and no longer use them. One was melting, turning black, smoking, and almost caught fire after running at capacity for a long period of time.
About that fire extinguisher - you might want to get one with metal handles. I've heard stories about the plastic ones breaking during test. (Especially if you fail to properly remove the safety.) They're a little more expensive and a bit bigger, but still a good investment.
Thanks for the tip!
@@HamRadioA2Z Another tip: Get CO2 extinguishers for dealing with equipment fires. The other types will make a mess of things and potentially create a bigger problem as the electrical fire heats things up.
@@russellhltn1396 I usually reccommend Foam extinguishers. Sligthly less effective than powder, but doesn't destroy everything that the fire didn't damage.
@@HamRadioA2Z Have you ever seen the mess created by a dry powder fire extinguisher, especially in a relatively confined space?
What makes matters worse..the powder is hydroscopic, and will corrode metals if you don't vacuum every last trace.
Go dry water mist good on most fires and using reverse osmosis water it's none conductive and once dry leaves no residue
You've created some work for me with this video... Thank you.
Same haha...damn.
In the UK, I have found those "cheap and nasty" fuses have blades made of aluminum 0.5mm thick. The decent fuses have blades made of nickel plated brass, 0.7mm thick. So there is potential for the cheap fuses to give a bad contact. I once made sure I gave eveyone in my car club a "free fuse" and told them that if you can easily bend the blades like you can on your free gift, don't buy it...
yes, my experience Aluminum is soft and forms a high resistant connection over time. Dito throw away the non-branded fuses.
Brass is a pretty dismal conductor of heat, whereas aluminum is as good as it gets, excluding copper and silver. Since fuses are really just self-heating resistors that melt themselves to oblivion, removing heat "too fast" will delay or even prevent blowing.
@@raymiller5738
That's why aluminum has been largely banned for AC mains wiring - joints tended to be unreliable and cause fires. There are problems with both oxidation (aluminum oxide is an excellent insulator) and "cold flow."
I have a small single-AA cell, single mode flashlight I really like except for one problem - the tail cap of case was notorious for going high-resistance between the cap and body threads. A tiny bit of a zinc paste (Gardner Bender OX-100B), intended for use on aluminum wires, on the threads fixed the problem nicely.
Great job!
Sometimes a return to basic component information is invaluable. I think another component that needs examination is clone Anderson Power Points. Many of them look right, but do not use the proper materials and arc at very low currents!
Hope you'll do more things like this....
I have heard about fake PowerPoles. That’s another one I need to check into. Thanks for mentioning it.
I was scrapping a Fiat and cut a wire of the fuel injection on accident.
The fuse of the fuel injection melted it's casing and later the entire socket but did not blow . The wires started burning first. It was an original fuse
A very good demonstration and an eye-opener to modern day equipment. I have very little new equipment as I am a homebrewer and operate boat-anchor vacuum tube equipment. The fact that the voltage on the power supply drops to 0.6 volts and still maintains 20A is amazing to me. That is 12 watts of heat being dissipated in the fuse, as your temperature measurements indicated, which seems like it would melt the fuse link in a reasonably short time. Apparently not...
My power supplies are all the linear brute-force type and shorting one of them will likely not drop the voltage any significant amount so we would end up with the full 15 volts (as in your example) at 20A for 300 watts being dissipated in the fuse and we all know where that is going to go and hopefully the fuse will protect the equipment from catastrophic damage and possible fire.
With over-current sensing in SMPS in modern equipment, it almost seems redundant to put a fuse in the output side, although I think it is still a good idea. 73 WA4QGA
I'm most impressed! Very important info. Now I got to go check my fuses. Don't forget to check what goes in your car, lots of sensitive stuff in there.
This topic was covered a year or more ago, with comparison tests as well. ALL the colors of blade fuses from parts unknown would hold 40 AMPS ... be they molded as a 5, 10, 20, 30 OR 40. A USED CAR LIKELY HAS SOME OF THESE. The hazard is from putting in a no-blo fuse into a bad circuit that popped the GOOD ( blown ) fuse, without diagnosing and repairing the vehicle. Expect to ruin a wire harness or worse.
Hi, Tom. Thanks for the very informative and interesting video. Blade fuses are a type of commodity item I've never really thought twice about. I guess not all of them "just work". I'd hate to have one of those 5A no-name fuses "protecting" a sensitive circuit in my vehicle. Well done.
Marc (N1QGM)
Same here - I never thought you could screw up a fuse!
Pay attention. Any fuse like these, no matter what manufacturer, will NOT protect 'sensitive' equipment. They are only intended to protect wiring systems.
I remember a Marconi engineer looking at a duff transistor. "The three pronged fuse has blown!"
Thank you very much, I have same that unbranded fuse and I tested them my self... man they are unblown able ☠️☠️
I had some of these no name ones in our Peterbilt fuse panels until we found out some of them would actually catch the plastic on the fuse on fire and still not blow the fuse! Never again.
This comes as no surprise to me, Chinese manufacturering often times substitutes for materials that are not in stock or considered too costly in their opinion. They probably substituted aluminum wire for the tin or indium fuse element. One clue is the DC resistance, it is most likely abnormally low.
I discovered similar problems with the Chinese marine style thermal circuit breakers 3 years ago. These trip at 1/3rd to 1/10th the stated current. They can also chatter when they are about to trip. I finally had to test each breaker for it's trip point, then label the breakers accordingly.
I have also noticed that the blades seem to be thinner and have bad contact with some fuse holders.
There was a massive recall of these fuses a few years ago, because the only difference between the fuses was the colour of the body, as they all used the same stamped out fuse element, and simply put a different colour body on the top. Millions of boxes recalled, they had to go somewhere, so likely got sold off as lots cheap. Basically look at the elements, if they are all the same size they are all 30A fuses.
Extremely helpful video! I've got a package of Bussman fuses on order and am going to swap out all my current no-name blades as soon as it arrives. Never thought about fuses before and just assumed a fuse is a fuse is a fuse. Thank you so much for this informative video! 73!
Ok, you've spooked me! I like littelfuse but have some cheapo genetics. Ordering replacements now. Thank you!
I had some of these fuses around and used them once for some relays, a fan they were controlling got jammed and it should have blown the fuse but instead melted all the plastic off of the fuse and got everything pretty hot. I bought a box of legitimate brand fuses and made sure that I never used the cheap ones again.
Great video! Excellent warning about cheap fuses that often get taken for granted. Please note though, that those types of heat guns observe a rather large conical region in front of them to determine the temp. They do NOT measure the point at the red laser dot. Unless one is measuring a larger area (like a frying pan for example), they are inaccurate for small spot measurements like the fuse - the fuse is likely to be much hotter than one it displays since it is averaging same of the desktop temp with the fuse. Nonetheless, awesome video. Will be sharing this with others!
It seems like the manufacturer's testing methodology involved either dry labs or shorting mains.
I got a bag of fifty 3A ATC fuses. I'm good to go for all my needs. I've been testing DC disconnect breakers. A 10A won't even trip at 22A.
I have considered doing a video about breakers. Even good quality circuit breakers take longer to trip than a fuse because of the nature of how they operate. As I said at the beginning of the video, fuses and circuit breakers are primarily designed to protect wiring from catching fire. They’re not really designed to protect our electronic equipment from internal faults.
@@HamRadioA2Z You might also want to look at DC breakers. Some of the polarized ones actually interrupt the arc faster when connected in reverse. I get all this stuff free from manufacturers. Sure glad I'm not having top for some of these products. It is the wild west on these CE listed products!
Well I’m about to order some new name brand fuses and throw out all the no brand stuff on my bench right now.
Thanks Tom!
There's over 12w dissipated in your setup with the Chinese 5a fuse, yet the temperature rise after a couple of minutes is less than 70deg C. Metals and alloys are not likely to melt at this temperature. It most likely that they are using copper or some very conductive material in the fuse, instead of the right alloy. The power from the supply is being evenly dissipated in the cables and fuse instead of the fuse heating significantly more than the cables.
tinned copper wire can be used as fuses, its whats sold in small cards as 5, 15, and 30 amp fuse wire for use in rewirable 'consumer unit' fuses
Thanks for taking the time to share this information! Before throwing them out, maybe test them on a car battery in various parallel configurations. Then maybe you can repurpose the 5A fuses to protect 00 wire...😛
I was randomly recommended this video and straight up bought spare bussman fuses (the littelfuse kits were about the same price) just now. Glad I never had to use the spares I bought a couple years ago, those will go straight to the trash. It seems like the knockoff kits spent all of their money on a case so maybe I'll put the good bussman fuses in that. Thanks!
For 44 years, I taught aircraft electrical/avionics/weapons control systems maintenance. I do not remember one new student knowing the true purpose of fuses/circuit breakers. When we got done, they knew.
Had always assumed a fuse was a fuse, and even though I have a couple kits of brand-name fuses, I also have probably that exact same kit of generic fuses. Throwing it out. Thanks!
Excellent video, thanx for the warning. I did buy a non-branded kit "ABN". Tested the kit on my PSU and the fuses up to 20A cleared in a timely manner. Looks like the fuses you had were just bits of wire between the lugs... Thanks again.
Thank you for this video! I had cheap fuses laying around and tested them, this is what i found:
1. 3A fuses did not blow at 10 amps even after 3 minutes
2. My switching-mode power supply blew a couple of 2A fuses at
Thank you for your excellent review. I also purchase a box of 300 no name blade fuses from EBay for $16 and had quite a different experience. I replace the original 30 Amp fuse with one from 30 Amp fuse from EBay that is in line with a solar regulator. The solar regulator runs a maximum of 25 amps and the plastic that encapsulated the blade fuse wire melted exposing the fuse wire. It seems that they made of a plastic with a very low melting point. I wonder if the current did get to 30 Amps or above 30 Amps that it would catch on fire.
Thanks for sharing this. I always say that government has a function. One of those functions is to protect consumers.
When safety devices fail to do their job, the government should prohibit their sale as a risk to safety.
My only concern with your test is you showed only one test of a 5 amp fuse. I'd like to see the results of 5-5 amp, 5-10 amp, and 5 -15 amp fuses.
Certifications are important. But even without them any safety device should perform as expected or be prohibited from sale.
I did try several of the 5’s with similar results. Stay tuned for a follow up video.
Yeah, well, it seems the government is about as effective as these fuses, but we don't get a bargain price for them!
Thanks Tom,really good info. Never gave it a thought till now will check my that hang on wall. Thanks again.
The best thing about the no name fuses are the cases, and they often come with pullers. So toss the fuses out but keep the case, and then put in brand name fuses. A lot less finicky to open than the Littelfuse or Bussmann cases, for sure.
UK mains plug fuses come in 3 and 13 amps mostly. 1,2,5,7,10 amp also. They look like 1 and1/4 inch ceramic fuses except 1 inch. A UK kettle often uses the full 13 amps ( 12.67A 240V mine ). This is often Bushmann fuses and relaible or years. These fuses were a way to reduce copper used in wartime circa 1943. It actually reduce impedance as it's a ring circuit. It also protects the power cord. The fuses are 15 cents. The ring is 32 amps. 6 amps lights on a radial. 100 amps typical company fuse. I once installed a 6.3AT 20mm fuse on a10 amps kettle at the factory. The staff knew. Months later it still worked. It was high grade. The graphs sort of said it could. Although I didn't ask 1 minute could be the cycle time for a mug or two of tea ( 50 a day ? ). This was to test a real application.
I've been seeing some strange failure modes with older H-type ribbon Buss glass fuses. The fuse blows in the center, deposition coats the glass, and the remaining ribbon ends sag and reestablish a resistive contact. The circuit looks like the right voltage is there, but can carry no major current. Twice in 2 years.
I actually ran into this myself doing load testing for sizing the fuse for an electronics project - I use pico fuses which are about the size of a grain of rice. The Amazon ones listed for 500mA fast blow didn't blow until over 1.5A. Some knock-off Littelfuse ones I found on there too, rated for 2A Fast Blow, didn't blow until they had almost 250% over their rating (4.5A), and that was ratcheting up the current quickly. I got on Digikey and got genuine Littlefuse pico fuses, and they all blow at almost EXACTLY their specified current. It's almost like these Chinese companies just stamp out fuses from any pot metal they can find and then injection mold it. It's truly scary if you think about it.
Nice video. And also a very important topic. These cheap "dummy-fuses" won#t save you a penny, if your car or even your house catches fire and burns to ashes. But, just for showing the seriousness of the danger (and for fun), you should have used thinner wire, that actually melts or lights up.
Anyway, amazing video, thank you. 73s
I wanted to blow a no-name 15A blade fuse recently and tried to use a car battery to do it. It isn't a handheld project, I found out. I didn't think hard enough, that maybe the cheap fuse was the problem.
Thank you for sharing your testing, something I had not been considering a potential issue. I will examine and replace all my fuses now as well.
Thanks for the tests. Just 2 comments, it could be sped up only, mentioned twice sloowly the ebay amazon (we got it the first time around! ;)). Second thing the mic scratching can be painful after a while. I hope it will help make your next viseo even better!
I was reminded long long long ago that my auto instructor said you're paying for the metal they use for these fuses, & they were coming from a place of experience.
You have illustrated overcurrent protection in the precise way it is intended to work. The startling issue I had not expected is the lack of specification on the chinesium fuses. Very nicely done and an important warning.TNX
It would be interesting if you did a follow up with the 5A fuse with a teardown, and see exactly why it doesn't blow.
I just tore down one of these fuses, the fuse is made out of aluminum, to get a fuse to blow the wire has to be a specific diameter. Each fuse is cut from a flat plate of aluminum, probably in a stamping machine. The theory is that the machine stamps the wire accurately to a specific size. My guess is that the metal isn't the right material (they just used a piece of ordinary metal) and/or the stamping machine is highly inaccurate.
Its a QC issue obs. And tearing down fuse...mate😂
They are all stamped to be 30A fuses, just the colour and embossed amps is different. Done to reduce cost, as the 30A unit is the most robust, and cheap to make, and then you just put the cover on to make the others. They were recalled as defective years ago, but are still sold cheap in kits, because there is no QC done on them at all.
If you see a box compare the fuse element between the ratings, they are all the same size, while real ones the fuse gets thinner as you go down, or it is a thin wire spot welded or crimped between the blades on the lowest current ones.
Wow! You're right, thanks for testing these. I have a box of no name fuses also, I just tested several 5 amp fuses on a quality 20 amp power supply - they didn't blow, I even tested the ten amp fuses.
Wow! I'm not a radio guy but really appreciate YT for suggesting this video. I recently bought one of those cheap fuse kits on Amazon to keep in my RV. Not only will I toss that kit out but I'm going to have to go through all the fuses in my coach because I've a bad feeling that the manufacturer of my RV may have used these cheap fuses. I can only wonder how many camper fires might have been caused by one of these poorly made fuses. Thanks!!!
Great knowledge. I` m going to check all my DC fuses in our RV.
Thanks I'm changing my fuses today!
Very good illustration.
I look forward to seeing the crowbar device. I’ve always been mystified that little premade in-line crowbar devices aren’t on the market. I’d love to see some adjustable ones that could be used on 13.8 or even 5v applications.
I tend to tinker with power supplies and have modified some to have remote sensing, but I’m always worried that something will go wrong and the devices being powered could see high voltages if the sensing wire ever became disconnected.
If the supply lines are big enough to handle the current, there isn't any need for sense lines, unless you have some very fussy equipment, but even then, increase the diameter of the supply lines to meet the demand without excess Voltage drop.
A crowbar design is quite old-fashioned. There are modern power switch solutions that are faster, more reliable and optionally auto-resetting.
Thank you for testing these fuses, and for making this video!
I'd of never thought that no name fuses would be THAT bad! I think I have some and will check them and probably through them out. Thanks for making this video. I too am a Ham Radio guy.
To just test fuses you can make one of these 2 cheap and easy solutions: Microwave transformer converted to high current transformer, and adjust the primary input with a variac/autotransformer, Or use a car battery and have some adjustable load, like a combination of big resistors, a diy basic transistor load, a chunky dc motor and braking progressively, or something else that you already have at hand. To measure current, a current clamp would be the best option for this kind of high currents.
I tested the set that I have, and the fuses are operating correctly. They blow in 1s at 2x rated current. The only slight issue that I don't know if it's normal or not, at 1.3x current they glow red and melt the plastic a bit but they do eventually blow. The set is Herbert Müllner BOX-AS147. They are visually similar to yours with the embossed current rating that's hard to read but have a different fusing element. So it's not possible to distinguish good from bad just visually.
Great video Tom! Maybe you can repurpose the fuses into current shunts for amp meters. I usually use buss man or little fuse. Another problem I have found with the cheap ones in oxidation. They build up and become resistive dropping the overall power. 73
I don't think you want to use those as shunts for an amp meter. If the fuse should melt, POP, there goes your meter.
@@waltp3373 Absolutely!
I have my fuses from Ali or from al local store which is called "Schraube" it means screw. I will test them tomorrow. Very important video
Great video.. I was just mentioning to my brother a few days ago not to buy no-name fuses and to stick bussmann, etc. For individual fuses, I usually purchase them from digikey or mouser to be safe.
Tanks Tom another really informative video. Look forward to more in the future.
get the oscilloscope to measure across a high current shunt and use a car battery across the fuse to blow it up. the shunt will measure the time + peak current require to blow the cheap vs branded ones. and i always use little fuse. , i keep a box of their energy kit in my car although i have never needed it. but i do use blade fuses everywhere. they are easy to replace and works fine for low voltage dc.
This isn’t a good test. The peak current will be enormous - hundreds of amps - for any fuse you put in there.
@@stargazer7644 that would be a realistic test because these are connected directly to a car battery that can deliver 600amps under near short circuit. So if a module or accessories goes short then you also need to know the peak current and the time it takes for the fuse to blow. Because a storage oscilloscope can time it down to nano seconds.
@@KuntalGhosh A fuse is not designed to limit current before it blows. I've never needed to know those numbers when designing a circuit. You simply use the fuse that is rated for the job.
@@KuntalGhoshA realistic test would be to connect the 5 amp fuse to the battery using 10 feet of 20 AWG wire. The resistance of the wire would be about 0.1 ohm. The resistance of the fuse in the test is about 0.025 ohm. The current would be about 100 amps. The fake fuse might blow before the wire was cooked, but I wouldn't count on it.
I had that cheap chinese fuse kit. After seeing your video 2 months ago i threw them all out and bought all Bussman. I did use the chinese plastic case.
I still have my cheap Chinese/noname fuses, but only for doing more tests or videos. Not using them in any of my active equipment.
I remember a 528e back when German cars use ceramic/thermosetting strip fuses . Red 16 white 8blue25. It was burned out in the roof from a dome light short. The fuse was replaced from white to blue.
WOW, that's unbelievable. I had no idea. I won't be buying those on Amazon. I wonder how accurate the auto reset blade circuit breakers are. I have a friend who has a box truck he uses for work. It has an intermittent short on a 15 amp light circuit. Sometimes it will go for weeks without blowing the fuse. I couldn't find the problem. I was thinking about mentioning the circuit breaker so his lights would come back on at night. Would you want to test those breakers?
Totally agree. Unfortunately it's really hard in the UK to find any parts like this that aren't cheap C...ese crap. Britain used to make all these kinds of things, but all those companies have long since closed down. I searched for ages and still couldn't find any quality fuses.
even 'top brand' stuff is often made in china, so much is, but made to the brands specifications by some third party manufacturer
Wow, so dangerous thanks for the video glad I only have standard height mini fuses that are no name. And my low profile ones are Bussman. Will be getting new fuses for digging into my families vehicles for the nonpainted no brand fuses
I was concerned about this exact issue, so I didn't get one from amazon. Thanks for confirming my concern.
I learned something about unbranded fuses thanks
Thanks for doing this experiment! Would you repeat it without that bench power supply, and use a car battery instead?
The current and voltage at the fuse under test could be measured with a two channel oscilloscope (one channel connected to a suitable current shunt) 73, de K7GVG
And add a contactor rated a few hundred amps, so it can be done out in the yard/driveway and switched on or off from a safe distance in case the wires blow first.
Ha, I bought a similar box cheap, recently. Gonna check this
I've seen many a piece of equipment with a piece of car antenna in place of a fuse, but I didn't know you could buy 'em pre-made.
Amazingly worrying - thanks for alerting everyone.