How many Amps to burn up 14/2 electrical wiring?
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- Опубліковано 7 сер 2022
- We overload standard 14/2 wire commonly used in Canadian and American houses to find out how much current it can handle before it melts and burns up. Spoiler: It handles way more than its 15 Amp current rating as one would hope for a good safety margin. Of course it should never normally to subjected to anything beyond than its standard current rating.
See the FAQ video about this and the other over-current tests here: • Overcurrent Tests FAQ - Наука та технологія
If you want to see MORE REALISTIC TESTS for various insulation types from fiberglass to foam in a 2x4 wall, look here ua-cam.com/play/PLHUfJmsprIcTVwSgCkTJnkinJSWrZY7DY.html
Can you do another video use 12-2 and run it through a wire nut , a wago , & just twisted to see which melts first?
@@thewonderfulwonder1614 I will definitly do some version of that - numerous requests for wage tests. It may have toi wait till spring unless I can rig up a fume hood in my basement!
Can you do this with a wago connector?
@@fernandoalcantar7907 Yes - have had plenty of requests for extensive Wago testing. Will definitely do it. May have to wait till spring since I cant do it inside due to the fumes.
I’d like to see a test that would simulate two space heaters running at the same time on a circuit of 14 gauge wire and see how long it takes for the wire to start toasting. Initially the wire can probably hold up but after say 10 to 12 hours that’s when it may start to fail. Many homes slap a 20 amp breaker on the 14 gauge wire incorrectly. So this is a real world scenario.
Would be good to have a thermal imager rather than relying on touching the live wire (that is rigged to fail). This was a great video though, none the less!
Your the second to suggest a thermal imager! I will have to look for one. Glad you enjoyed it!
Even a infrared thermometer would’ve been great to see actual temps!
@@dodgeguyz Based on suggestions like yours I did that in the "wire in fiberglass insulation" video I put up today: ua-cam.com/video/Df7bAEdIILI/v-deo.html
Its not like touching that "live" wire is dangerous other than possible burns if its that ridiculously hot, but this is less than a volt for most of the test, so its doubtful that you would even feel a shock until the mid 20's or even 30v.
It's classic UA-cam style...let's hookup electricity and use my fingers as the measuring device! Woot woot Science!
Keep in mind this experiment has the Romex in open air, which is reasonably good for letting heat escape, instead of passing through insulation in a wall cavity. Also he's only giving it several seconds to heat up. Don't use "didn't catch fire after 10 seconds in free air" to decide what wire gauge you will use inside walls!
If the jacketed wires are warm on the outside of the jacket, they're hotter inside the jacket, and hotter still inside the wire insulation. And most of us hope our house wiring will last for decades.
6:50 watch the voltmeter climb: the resistance of copper wire increases with temperature. It's getting hotter.
Great comment and let me add to that. Any experiment - mine or someone else's, should not be taken as any encouragement or suggestion to use anything other than the approved wire for a certain application. Its just interesting to see very roughly what the safety margin might be.
It was just academic. Obviously you should follow electrical codes.
@@shaunnightfire8269 My thought exactly!
I’m just a homeowner handyman, but I think you would have entirely different results if you used a length of 100 feet. A short 5 foot length is not meaningful and leads to incorrect assumptions
@@dustmaker1000He mentioned resistance around 6:30. 100’ sounds a bit long for household wiring unless you have a very big house. I’m trying to remember the longest run of my old house and I don’t think it was too much more than 50’. Perhaps 60’. 🤷🏻♀️
Note the voltage drops at 8:22. That drop in voltage means the resistance decreased. In this setup, that can only mean that the wires are now touching before they get to the wirenut. In a voltage driven circuit (such as household power) at that point the current and power would have gone way up. Since I think we can assume that to get to that point the circuit protection has failed, at that point I would say the fire starts...
Good point about a real household circuit. One would sure hope currents never get to these levels. One commenter did point out how people upped fuse values in the old days if a fuse blew. So maybe back then sustained overcurrent may have been more common and there would have been the possibility of even the too large fuse saving the day when the wire shorted.
@@ElectromagneticVideos In the 50's, we replaced fuses with a few coins, screwing the bad fuse back in to hold them in. (After fixing the problem) Many people thought it was a permanent fix, but they caught on by the third or fourth rebuild. Other poor results are obvious by now, I hope.
Sorry dude... you need to test at 130volts 15 amps....
@@randytrant I was under the impression that current is the sole contributor it heating and voltage is irrelevant.
@@hhn2002 it is. 15 amps is 15 amps. Also current depends on how much voltage you apply. There is no way to limit current to 15 amps at 120v with just the wire resistance.
The temperature rating of that 14AWG NMB cable is 90°C. The amp rating is good to 25A. The NEC prohibits its use over 15A. Nice demonstration.
Thanks for the info!
Yes. The NEC has safety factor upon safety factor built-in. It’s apparent all across the code. Things can be stretched much past their code “limits” before catastrophe occurs.
@@alex43223 Very true! Although I was surprised how the safety factor becomes in some later experiments I did with 14/2 inside insulation as you might get in an outside wall.
So the wire hits 90C at 25A, but is that buried in insulation, or hanging in free air? And NEC actually prohibits its use above 80% of 15A, or 12A continuous.
@@stargazer7644 The NEC allows wire to be used at 100% of it's rating continuously, it's the OCPD that's limited to 3 hours of 100% rating, anything longer than that it has to be derated to 80%. Any load that could potentially be on more than 3 hours at a time is considered to be continuous. So you are correct in that the entire circuit is limited to 80% of the OCPD rating, but the wire itself is not the limiting factor. Also, you cannot use the 90C table unless every device the wire is landed on is also rated for 90 C, and nearly all circuit breakers are limited to 75C. In the absence of a temp rating on terminations or connections, you have to default to the 60C ampacity table for the cable. Which in this case for 14/2 is 15 amperes. Mike Holt has some excellent videos where it's explained in more detail.
That was interesting AND educational! Well done! Never thought to test house wiring before, but I feel a lot better about the wiring in my house now.
Glad you liked it but things are not as good as in this video when in a real wall - did some later videos where I built a section of 2x4 wall with insulation around the wire. The safety margin goes down quite a bit as expected.
@@ElectromagneticVideos I would completely expect that. I'm a communications engineer, and essentially what you are suggesting relates to heat dissipation, due to the resistance of the wire, it develops into heat, and as long as that heat can be dissipated, the wire is fine, same deal with a forced air electric heater. If the fan quits, that wire is going to burn up unless it is protected with a heat sensor to shut it down of course. If you don't have a thermal camera, they are great investments, as you can find heat and cold leaks in your house, and they are awesome for troubleshooting circuit boards and defective components.
@@jimturpin I actually did get a thermal camera for the later tests - great toy to have! Communications Engineer? What do you do - I used to be involved in HF/VHF/UHF comms. Now I'm more in the faint signals detection type of stuff in the microwave bands. HF was great fun - nothing cooler than transmitting vast distances with a few 100w.
Try this with wire nuts and wego connectors and see which holds up best
You must have read my mind. I posted a video on that this morning! Here is the link ua-cam.com/video/cMVnOZCGljc/v-deo.html . Enjoy!
Oh nice. By zee way... where in the world did you come up with the idea of attaching a stinger to Romex, and various other things found within the confines of an electrician's van? This is quite a cool idea to play with.
@@DarthTwilight OK - I have to tell you the story! A year ago, I was at the local Habitat for Humanity ReStore and there was a vintage welder that had been marked down to $100 because it was not selling. I guess it not being DC was a deal breaker for most people. At $100 I couldn't resist and figured if I ever needed to weld something thicker than my MIG could handle it would be good to have. I also had at the back of my mind that it might be useful if I ever needed to do some high current tests. To put things in perspective, I'm an EE and always liked doing experiments of all kinds. It sat in my garage, and a year later (3 weeks ago) I was cleaning out some old extensions cords which I have always never trusted and thought - might be fun to see how bad they are before I throw them out. So I did (the video is there) and actually was impressed by the newer ones. That made me think - since I'm setup to do it, lets see what 14/2 can handle. Nothing very profound - just my idle curiosity and posted the video on my obscure little channel. I had no idea that it would get so much interest! Great thing is, many comments have been so thought provoking it had been way more fun that if I had just done the test and not posted it. The videos I have posted since then are all suggestions based on the 14/2 one.
Already been done by people who know how to spell Wago.
@@waytospergtherebro Ok Grammer Nazi. I guess when you work for someone else, aka to earn a paycheck, you need to worry about spelling. Thanks for pointing that out. I'll remember next time that I need to worry about it.
just an FYI
the adoption of twisting wires before putting on the connector came from the use of Marr connectors which had a small screw in the side which held the two wires together. if you didn't twist the wires then they became flattened as you tighten the screw and there is a lot of chance the cross-section area of The wire would become very reduced and over a period of time of heating and cooling the Matt connector would loosen off.
Ken
I worked in cable, when foreign voltage melted our lines, it was always at the splice points of the tap or the ground block. We could cut the melted part off and the cable would still be fine. You need to test a longer length circuit with multiple splice types for an accurate test.
Torque screwdrivers! Use em!
Great demonstration. Thank you. The wire can really take quite a bit of amperage before it failed.
Honestly this is a terrible test. it gives people the false sense of safety on residential wiring.
no one should put 60 amps at 120v AC through a 14/2 wire. he had it at 2v before the coating started to melt.
your house doesn't run on 2v AC..
Pretty Cool.. I'll never doubt wiring up a motor again with the yellows!
Yes! They are amazing good at higher currents!
Very cool demonstration. Thanks for sharing.
Thanks for your comment! Glad you enjoyed the video!
Growing up I remember just sticking in ends to see if it fits whatever it was I was trying to use and if it fit it was the right one. With that said, I’m very impressed I’ve never set a fire but I definitely gave my kids a live performance like you did here, showing how a cord will catch fire if it’s not meant for the device or the devices board will fry ruining it.
Always great to expose kids to science experiments if done with the appropriate safety precautions. Most kids naturally love finding how things work - at least until some of the textbooks used in school drive any intensest in the subject away.
A few years ago I was doing some welding, and absent-mindedly attached my grounding clamp to my bandsaw, and the return current found it's way through the 120 volt shop wiring. It lasted about 20 seconds at 75 amps before it let loose. Lots of charred insulation.
Oops! So you did my test before I did! That must have been a real pain to fix!
@@ElectromagneticVideos I was lucky- most of the current path was 12 gauge, and it survived fine. There was only one section of 14ga. that I had to replace
You will Be suppressed how often this happens in workshops. Especially with the older non inverter welders. The return path ends up going down the earth ( ground wire for you guys). This cable gets so hot it melts the insulation on everything. The new inverter welders tend to run earth free on the outputs and is less of a problem, ( I think this is the case but never actually tested it). If your work is touching the building steelwork make sure you have a good return connection
@@johnwarwick4105 I didnt know it was a common thing. Surprising that someone didnt make a current sense relay module for the welder ground/earth wire that would disconnect power the instant that happened. Could have have prevented what I'm sure were costly accidents.
I'll bet your right about the inverter ones (or at least some of them) having. I have done a fair amount of switching power supply design, and many have no electrical connection between primary and secondary. There might be a regulatory requirement for a ground connection perhaps for some perceived safety issue or RF suppression although I'll bet many on online sites might not exactly be built to adhere to any standards!
The voltage suddenly dropped to nearly half at the point that the insulation began melting even as the copper heated and began increasing its resistance. Then it began rising again from the lower value.
I suspect a short part way along the cable, which reduced the impact further down the line (eg: at the far connector).
Great demonstration and demonstrates a (very) good reason to use fuses or circuit breakers...
Thanks! Yes - and probably a good example of what happened when put a penny under a on old screw in fuse in the old days ...
When I bought my home 10 years ago most of the house was wired with 10ga cloth and vinyl wrapped wiring, with some scattered modern 12/3 for new outlets added, and they added 10/3 to dedicated outlets to each window air conditioner outlet.
The worst overload was the living room which had four lamps, each with a 100w bulb and run off a single run of 12/2 w/o any ground, which also included the front porch lights and two outside outlets and four single bulb fixtures in the basement below, each with 100w bulbs.
It showed no sign of any failures but I did run new 12/3 runs to each outlet, one to the porch and two to the basement lights on that side when I tossed the old screw in fuses for a new breaker panel. The old wiring was plastic insulated wires in some sort of silver cloth wrap.
A few bulbs in the basement still have that wiring but little by little I'm replacing those fixtures with LED units, and for now, every bulb in the house is LED.
I lived in a few houses with messes like that. An some that included silver cloth platic wireing that I think came just before NMD. Sounds like your a bit like me - every home I lived in was safer when I moved out than when I moved in.
that doesn't seem overloaded. 12/2 can handle 1900w without issue and upto 2400W for non continuous loads, if it was overloaded it would continuously flip the breaker
This was interesting to see, and one should keep in mind this is in open-air. If you had a fan blowing on it, it would go higher, and if you put building insulation around it, it would heat up much faster and support less current. Finally, the fact it burned at the corner is also a clue, the thinner the wire is at a particular location, such as a bend or pinch-point, the greater the resistance there, and the more heat generated. So, to compensate for all of those factors and more, it is rated for 15A max to ensure safety.
Very good point. I actually did follow up experiments with the 14/2 in a fake 2x4 wall filled with various types of insulation and the results are exactly as you predict.
Do it again with home insulation around the wire.
Many people put their wiring buried in home insulation.
Good demonstration.
I recently left a wheelchair manufacturing outfit and part of my job was testing the electronics modules. The motors on ours were fed with No. 10 stranded wire, and if you stall the chair against a block and firewall the joystick, they would pull over 200A for a short time, which amounts to approx 100A per wire to the motors. No ill damage occurs.
The key is "for a short time". Not long enough to heat up enough. I assume the system has some sort of current limiting in the electronics in case of an extended stall?
Brilliant test
Glad you like it!
Testing to failure is aerospace-level stuff. Thanks!
Its always interesting to see when things fail!
This video reminds me of some scary pages on the subject of Federal Pacific Electric breaker panels. Despite several design revisions, independent tests have demonstrated that the circuit breakers in these panels are prone to failing to trip.
Yes - I have read about them too. Its hard to imagine how much worse it could be with those breakers. While the simple heating and melting of the plastic wire insulation would be similar if someone plugged in too big/many loads like heaters, once a short did occur in the cable as a result of the plastic melting the AC power system would not be inherently current limited to a few hundred amps like the welder is. You could easily expect 1000s of amps flowing and the copper wire vaporizing. Hopefully the main panel breaker would trip fast enough to prevent a more catastrophic result - no idea if the main breakers have the same failing to trip problems....
i still replace those zinsco breakers with aftermarket ones- people dont want to spend for new panel- although i tell them the dangers
I've always wondered about this! Good video
Thanks!
The voltage measured is only the voltage that is not consumed by a dead short thus your wattage calculation is not correct,the better method would be: use a 12 volt car battery as a source of power and a carbon pile load tester instead of the wire nut, then increase the load with the carbon pile. A reasonable car battery should be capable of ( note the term "about") about 6 to 7 thousand watts for about 10-15 seconds.....the 14 gauge wire will probably fail well before that level.
Good illustration. Thanks.
Thank you!
Super video! I see a few suggested a thermal imager! Also would be cool (actually hot) to see actual degrees temperature along with your observations as to touching and explains the heat! Again, enjoyed the video!
Glad you enjoyed it. I'm getting more and more tempted to get a thermal imager. I do have a thermocouple temperature probe on order. Now that I think of it, I wonder if my IR temperature gun would work or if the wire is too narrow for it.
@@ElectromagneticVideos It would be worth checking and seeing if your IR temp gun will pick it up.
@@unclemarksdiyauto I will!
Sweet video. Intentional electrical fires in the garage has been a pastime of mine since it was my parents complaining about the smell. Would be interesting to see how different environments effects this, such as bundled conductors, passing through studs, different conduit types, or buried in insulation. I’ll have to do some tests of my own.
Go for it! I'm going to try 14/2 though fiberglass insulation between studs and also covered in spray foam which should really hold in the heat and make cable insulation melt at lower currents. Conduit would be really interesting. I dont really trust the PVC conduit - if you try it please let me know!
@@ElectromagneticVideos i dont trust the pvc conduit either, keep the videos going!
The connection point to a cheap receptacle .
Makes a super hot spot. That high current kettle in the kitchen. Is a prime place for a fire.
@@assassinlexx1993 And if the kettle itself is old with blades on the plug being tarnished, put that in your cheap receptacle and the combination is even worse!
@@ElectromagneticVideos electrical tea kettles ?
Thank you. Just the test I was looking for. 👍
Glad you liked it! A word of caution though - as some later experiments in later videos showed, if 14/2 or any other wire is surrounded by insulation the safety factor between rated the current and the overload current when bad things begin to happen drops considerably.
As a 66 year old Master Electrician I appreciated your test. It helps to see the tolerances of the material we use in the field so we have a better foundation to talk to our customers. We all go through the classes and books but to actually see the breakdown of the conductor is impressive. This gives me more confidence in the load carrying capacity of house wiring especially with today's insulations which raise or lower the load capacity. Thanks ;)
I glad you found it useful. I did a few other videos with 14/2 in 2x4 walls with various types of insulation such as fiberglass and foam. I am actually a bit concerned about situations like a fully loaded cable between piles of insulation in hot attic in the summer running an air conditioner. I would probably ask to have the wire increase in size by a gauge or so in situations like that.
I'm an electrical engineer so I don't get to see the real-world examples of things the way you do (and also usually deal with low power RF signals most of the time). Have you ever seen NMD or other cable damaged by running close to the max rated currents when situated in the middle of insulation in an already hot environment? Any sense from your experience how close to the edge of the safety margin we are with modern cable and insulation?
@@ElectromagneticVideos Well in the field we follow the NEC which requires no more than 80% load on any circuit and manufacturer recommendation for dedicated circuits for apparatus like dishwashers, A/C's etc. so for the most part we do not see break downs like your test unless the work is done by unlicensed people like Home owners who simply wire to make things work not considering potential consequences. However with the advent of more home generation equipment and EVA's and other new apparatus, I can see more overloads and fires with misapplication and improper wiring of such equipment. I will say I see a lot of interruptions and breakdowns using these Mexican made receptacles, switches and foreign made new light fixtures which do not have the same oversight in manufacturing that used to be the standard in US made parts. Especially after NAFTA which made foreign made material the standard in the construction industry iMHO
What I would love to see is more test videos on Service Equipment in todays environment using ARC FAULT devices. I see these products not proven in todays world. But time will tell. Thanks again.
@@carylamari6546 I actually also have seen scary stuff done by homeowners. I have a buddy who does home renovations on the side and you wouldn't believe what was in one of his projects - the previous owner (and I am embarrassed to have to say was an engineer!) used everything from speaker wire to coax to hook up additional light fixtures and outlets. We spent a fair amount of time searching through things just to find the hidden things to point the electrician to to remove or replace. I wish I had been making video back then. What an example of what not to do! The plumbing was equally "interesting".
Interesting you mention home generation and things like EVs. I will be adding some (used) solar panels to my house and have been researching the often not too to well publicized specs of the breaker panels when attached to loads + generation sources at the same time as the grid. I can sure see how things can go wrong if the panel bus rating is less than the sum of power sources if large loads are attached in spite of everything having properly rated breakers.
And yeah - general cheapening and lower quality parts does not help!
@@carylamari6546 Well I just came across some Cutler-Hammer Arc Fault receptacles on sale, so I will be trying to see what sorts of arcs can trip them. Still have to figure out how to do it - probably with everything running though either a gfci or isolation transformer (I have kw sized one) and making the arc using a switch with poor snap action or some sort of touching cables current limited buy a light bulb ... . So Arc Fault stuff to come in the future!
A good idea would be to use an infrared thermometer.
Always good to remember that the capacity of the wire is a factor of length.
A short wire is a lot more robust than the same wire at 250'
In the real world yes, a longer wire increases the voltage drop which then further increases the current. For this test its irrelevent. Resistance and heat dissapation should increase equally as wire length increases.
@@otov100 could you please explaine how?
Can you please explaine ?
@@insylem one would think that for uniform wire what matters for failure/melting is wattage dissipated per unit length. Since resistance grows linearly with length, voltage drop and total wattage grows linearly with length, and wattage per unit length remain constant
@@otov100 in the real world the shorter wire isn't more robust though. A 250ft wire will fail at the same current as a 2ft wire. That larger voltage drop is spread over a longer distance so the heating per ft stays the same.
But you do end up with much less usable voltage at the end
Great demo. I like your narration through the increasing amperage. Make sure to remind folks to not try this at home.
Thanks for sharing.
Thanks - glad you liked it! Yeah - maybe I need something at the beginning of each video saying "don't try this at home". Do a have warning at the end ....
@@ElectromagneticVideos yes, I saw the warning at the end. I noticed you stated the 14 ga wire was only supposed to carry 12 amps in a home situation. You did a great job. Thanks again.
@@thomasglessner6067 I really appreciate that Thomas! You know what was a disconcerting surprise to me - in some of the videos that came after this one I built a 2x4 wall section and did similar things with the 14/2 inside between insulation. The safety margin drops so much in that situation that if I was building a new house today, I would make sure 12/2 was used at least everywhere it goes though insulated outer walls or (worse) hot insulated attics.
I once ran a 1500(?)1800(?) watt space heater on a 100 ft 12 gauge extension cord that was wrapped around one of those plastic circular cord wrap things- so the cord was insulating itself from cooling off.
I was just going to run it for 20 minutes so I thought it would be OK.
I ended up falling asleep and when I awoke suddenly 5 hours or so later and ran out to the garage the whole garage smelled like hot plastic and the cord insulation was noticeably soft.
It permanently changed the insulation on the outside of the extension cord
Wow - what a real and scary example of the damage that can occur from current overheating the plastic insulation. Interesting that the insulation was permanently changed. I what what chemical change was caused by the heat on the plastic.
@@ElectromagneticVideos I'll try to get a picture of it and send it to your email in the next few days.
Still kind of spooks me a little bit.
I had an InstantPot that had some kind thermal event too. It turned off before there was any damage to the counter but the IP was shot and wouldn't turn on
@@jeffa847 That would be interesting to see.
I wonder if the instapot had some sort of internal thermal fusible link that saved the day after whatever failed.
14 is rated at 20 amps in the table , derated to 15 for safety and again to 12 continuous.
at this rate why not derate it for 0 amps. thats 100% safety.
rsA couple of things.
I'm not sure the wire nut had the full 60 amps at all. it looked to me as though the wire had melted and shorted at some point, diverting the current away from the wire nut. Nevertheless, it did hold up pretty well which is good news.
The real 'safe' current carrying capacity depends on more than the wire itself, but also in all the situations in which it might be installed, according to regs etc. Even a much lower current will cause a failure if the wire isn't able to dissipate the energy at a temperature below the plastic melting point. That's why extension leads should always be completely uncoiled, regardless of the length actually needed for a given application. I've seen whole rolls of extension cables drums fuse into a solid mass of plastic - even when used well within the rated capacity of the wires.
I worry that people watching your videos might come to an unsafe conclusion, thinking that a 15 amp wire (which as you say is only rated for 12 amps continuous), might actually handle 20 or so amps - way below the 60 amps you demonstrated to be a problem.
I once witnessed a house fire in a house near me. All put put fairly quickly once the dire department showed up. On investigating the cause, it turned out they had trapped a thin brown two wire extension cord under the leg of a desk. Even though the load was way under the limit for the wire, being trapped in a tight space, the wire slowly got hotter and hotter until the wood of the desk leg itself ignited. If the wire had shorted, it would have presumably tripped a breaker and not started a fire.
Interesting video, but of you can, please make it clear that no-one should run wires anywhare near their maximum continuous current ratings. Even if the wire nuts hold up.
Cheers
"I've seen whole rolls of extension cables drums fuse into a solid mass of plastic - even when used well within the rated capacity of the wires." I'll bet may extension cords are in use spooked up like that. Can sure see how the heat can build up dangerously.
Your point about warning people is well taken. I do say it in the description - would hope people read it.
60amp on 2v.. but if u have a supply of 12v and having a current draw of 60amp, that cable will explode in a instant.. its all about watts.. people should do the math..
Great video! 🔌⚡🤯Thumbs up for the Timex Ironman watch alone! 👍
Thanks! It was just a last minute thing that I ended up making this video and the previous one. Lucky I did - of all things it was this video that really got my channel going.
Like the weakest link in a chain, it's the compromised inch of copper wire or bad connection that starts the fire. Great test, thank you.
That a really good point - a bend, scratch, tarnished area, loose connection ......
It would be interesting to run a strip of this wire between some insulation and apply the current to see when it gets too hot.
I am actually hoping to have time to try something like that this weekend. I'm planning to use two 2x4s to make a simulated 16" OC section of stud wall with fiberglass insulation. Will also be interesting to see what happens to the wire in the holes in the 2x4s.
@@ElectromagneticVideos please make a video with different types of conduit (plastic and metal) to see how much heat is dissipated. I think with a metal conduit inside a brick wall you can easily overcurrent 2 times without issues.
I'm curious what the resistance is for the length of wire you used and if you tried a 30', 40', and 50' length of wire if there would be any difference in the results.
Exactly. That would make a marked difference!
Well for a given current which in a normal situation is determined by whatever the load is, the heat emitted per foot of cable does not change if the cable is made longer or shorter. Your right the resistance goes up for a longer cable, but the result heat is distributed over the longer length and the temperature rise remains unchanged. What does make a difference is if the cable in a wall filled with insulation and as expected things do go bad at a lower current. I did do a FAQ video here if your interested in more details: ua-cam.com/video/CP3-jcpzZeI/v-deo.html
NM cable conductor insulation is rated at 90C - 194F. The wire nut is rated at a minimum of 105C = 221F. NM amp in regards to the NEC is 15A
Interesting that NEC requires the wire nuts are rated at a higher temperature than the cable. I wonder if its because of an assumption that they might be a poor connection and more heat generated?
@@ElectromagneticVideos UL's connector standards try to assume worst case scenarios, there are some different categories too like usage in explosive atmospheres, Used to be that wire nuts didn't have a current rating at all and it was tied to ire size ampacity. But the basic connector standard now says 20 amps.
A lot of problems arose when there was a major push for WAGO connectors and adopting IEC standards, but the whole IEC standards are a joke! IEC does no testing and doesn't require any. 98% of IEC "certifications" are "self certified" by the manufacturer. Basically this means that the manufacturer attests to their device meeting the engineering standards. They use a statistical based "verification" process, meaning they don't question anything unless there are a very high percentage of complaints. In extremely rare circumstance, they may request 3rd party testing. Manufacturers are not even required to test or keep testing records, I've worked in industry for man years and IEC certified stuff is junk!
WAGOs tyoically say 32 amps on them and also has a UL certification. But the UL rating is 20 amps, 32 amps is the IEC rating! The Japanese rating on these is only 20 amps also. And strangely enough, Japan's residential voltage is 100 volts! WAGOs have been used all over Europe but they use 230-240 volts as the standard residential voltage. So on average, the typical currents for the same appliances, lighting, etc. operate at half the current of the same stuff in North America. So the odds of a statically significant number of failures is low and complaints are minimal. But all you need to do is take apart a WAGO to know it's not a good connection!
Part of the problem today is that most installers think certifications are equal. But the truth is that these standards ae apples tp oranges comparisons!
The inherent resistance of WAGO connectors is multiple times that of wire nuts. But because the dissipated heating is "I squared R" , twice the current is 4 times the heat dissipated. For the residential wiring installer, they just know that WAGOs are easy to use. Most of these installers have little formal electrical theory training and very few states require any kind of certification. I refuse to call these installers, electricians! They know how to connect things up and mist know the code, but few really understand the theory, Kinda like the cable installer guy who has no idea how the modem works! I find it interesting that WAGO markets to contractors but not engineers in the US. As an electrical engineer I would never approve or specify these connectors, I think these are probably OK for low current applications like LED lighting fixtures, but I would never use these in typical residential wiring.
'
The twist you have under that wire nut is better than average.
Thats an interesting point. In that case it may not be too representative of real situations. Of course the whole test was just a simple - for fun, lets see how well a wire can handle overcurrent.
I think testing it at the mains voltages(120v/220v)should give more realistic observation as the cable will be stressed both at high voltage and high amperage imitating the actual household scenario
Voltage doesn't matter
@@kylekirby6424 maybe you're right
@@AgentOffice Doesnt matter? Be caution! Its about the devices wattage. if u have for example an audio amp that will deliver a continu 600w of power, under a supply battery of 12v, that wire will explode at 50A.. u cant exceed max 10A.. its all about the delivered watt and your pressure, this wire can handle a device of max 100w
Thank you for noticing that! I felt like I was the only one lol I was thinking the same thing from the start of this video..
@@AgentOffice yes, the fuck it does… voltage makes a big difference plug 120 V lights into 240 V circuit. and you tell me what happens! But I will insist for you not to because of how destructive and potentially dangerous it could be!
Thx, excellent info! 👍👍
Lake Havasu 🌞 Az
Well thanks you! Lake Havasu? I have visited your area and walked on London Bridge!
Good test. Proves that 2 current carrying conductors of 14AWG not in a bundle can hold much more than NEC ampacity requirements. Would like to see thermal imaging after hours of 20A in a bundle of cables. Also, I have noticed that 12A through a 15A receptacle does heat up a good bit, fortunately not to the point of failure.
I have to do that! I once moved into a house where it turned out all the cables from the circuit breaker panel were bundled together along the beam under the ground floor and gradually one by one the cables were split of to whatever they were connected to. And the house used electric heaters. One of the first things to do was to spread out the cables.
Would there be much difference if you had say 50ft of wire instead of 3 ft? In actual applications, you wouldn't have that short of a wire.
The dissipated watts per foot along the wire would be the same for a given current, so for the same current the same rise in temperature would occur over the length of the wire. There is a corresponding per foot voltage drop (which in these tests is the voltage I put across the wire). So at the end of 50ft you would get a resulting lowering of the voltage presented to the load. At rated current on a typical branch circuit, I believe the code says no more than 3% drop is allowed. So for this type of overload on a long wire you might get perhaps a 10% drop lowering the 120V the load sees to 110V or less. If the load is resistive that would drop the current by roughly the same percentage. But if it is a constant power load like a electronic power supply or induction motor, the load will draw roughly that much percent more current making the situation even worse. Of course in a real situation the wire also goes though 2 by 4s, insulation etc probably making it hot at somewhat lower currents.
What if I did it in a vacuum at -50degrees with a three phase capacitor……….
@@dirkdiggler2052 I think you would need a flux capacitor for that :) Actually you bring up a great point - it is really hard to keep electronics cool in a vacuum. Infrared radiation and conduction of heat to other parts of the structure is the only way to get rid of heat. I know the Soviets actually used sealed boxes with gas inside holding their electronics to help with cooling. I wish I had a vacuum chamber to try 14/2 in a vacuum and see how low a current would melt it.
Well everyone knows that the white should have been connected to the return and the feed to the black. It burned because it had reverse rotation. 😂
@@intheharness :)
At 2vac 60amps the wire is only pulling 114watts, the wire is rated at 1,710watts 120vac at 15amps. Try this experiment again but with a load that doesn't short out the voltage :) still a very educational video!
120vac at 60amps would be 6, 840 watts, oh wow.
It doesn't make any difference. At 60 amps this cable will always drop two volts and dissipate 114 watts. If you jack the voltage up to 120 and connect four electric heaters to draw 60 amps, the cable gets two volts and the heaters will get 118 volts and dissipate 7080 watts.
Great video fantastic I always wondered about this wired lots of houses and things interesting
Well Thank you! I did a few more videos on 14/2 in common types of insulated walls in case your interested.
Thanks Dude. Cool video
Thanks@ Glad you enjoyed it!
With household wiring, shouldn’t it be 120 volts?
Voltage has little to do with testing the ampacity of a conductor
Great video, it's nice to know we can depend on our house wiring! Though most failures that cause fires happen at connections that are improperly made (untwisted wires inside wire nuts or loose screws at outlets). I'm installing Wago's now every time I have to do wiring around the house.
this test doesn't represent a residential application. the wire would burst into flames well before 60Amps at 120v.
do not try to correlate this test to your homes wiring amp capacity.
there is a reason 14/2 is limited to 15amps breakers. and 12/2 on 20amp breakers.
@@darkshadowsx5949 Obviously, but I'm just saying that failure points are at the connections, not the wiring inside walls, unless they are damaged somehow. A nail or a screw driven through a cable is never a good idea, but 💩 happens! Observing the code and minutea are your best friends.
I would like to see the same test using wagos. I think wego's would fail before a wire nut would. I don't think the wago holds the wire as tightly, therefore creating more resistance and heat.
Thanks for sharing your video give people an idea what happens when you overload your household wiring and how fires start in the walls with you knowing it to the house is on fire and it's to late you may lose your home ....
Thanks for this video. I now understand why our local code limits voltage drop on cables to 3%. In extra long cable the heating effect would be even greater and so the current capacity even less.
Yes - the longer the cable, the more total heat generated for given current and with a proportionally grater voltage drop. It is worth pointing out the heat generated per foot depends on the current (and resistance per foot of the wire) so the extra heat generated is distributed of the longer length and the temperature rise is the same regardless of length.
That's a good point. The code is based somewhat on voltage drop, not just heat in the conductors. A large voltage drop can burn out motors.
I would have liked to see how 12/2 wire would have faired. This would have been an excellent way to show viewers how circuit breakers work. Maybe the same test using a 15 or 20 Amp outlet. I've never seen an outlet on fire, thank GOD. This might be a wait-up-call for some people.
You know, might be neat to do a test focusing on the outlet - maybe even #10 wire and see what it takes to burn an outlet.
Receptacle, not outlet
Good test but time also plays an very important role. I tried the same thing with a 0,75 square mm (typical lamp wire size) wire and it could do 100A for about 10 seconds. Impressive but 10A for an hour or two will also melt it.
The real test would be to use a 15 Amp CB, and see if you can cook the wire without tripping the breaker
So, if 14g is approved for 15 amps, then how is 10A gonna fry it?
@@SomeDumUsrName he wasn't talking about 14g wire, from what I can tell. He said 0.75 square mm wire, which I'll assume is the common way wire size would be measured outside america. (I'm used to awg so idk)
Very bad example I would not call it a test. Use the formula not the amp probe. The resistance is for all practical purpose is 0 If you look on a breaker 15 Amps or 20 Amps they will read 10,000 Amps RSM 120 volts/0=( dead short) And also with # 14 which is rated at 15 amps. You are not suppose to have but 80% continuous . The capacity of a conductor is based on the insulation.
I was hoping this experiment would tell me what amps were dangerous with household systems. However it’s not obvious whether what matters is amps or watts. I’m guessing it’s amps in the wires rather than watts in the whole circuit. My mcb s are 15amp. The plugs and sockets and wiring are rated 10 amps. With a double socket it would be possible to have 20 amps going round with a kettle and toaster and maybe something else.
Thank you. I was curious about this.
Your welcome!
Twisted solid core wire can get brittle overtime, as well that it can be difficult for someone to take apart safely. If you want your wiring to last, no matter what you do, please leave an ample service loop if possible. You or the next electrician will be very grateful!
Very goo point about making sure there is extra wire length for future (re)work - such an easy thing to do yet some people seem to skimp on it.
The voltage tolerance on a 120 volt line in the US, according to the NEC, is 5% to the furthest outlet, or 114 volts. Most local power companies also allow 5% tolerance on the secondary side of their 7200/15400 lines, though the voltage is generally adjusted 2% over voltage to accommodate heavy evening loads when everyone gets home and starts loading the power grid simutaneously with H2O heaters, ovens, microwaves, and now, electric cars. I don't know why I find it hilarious that electric cars in many places are charged by coal powered facilities. Carry on sir 🙌
I guess that makes a Tesla a coal powered car :) People sure dont understand the greenness of electric vehicles is directly related to the power plants. Your point about voltage: With little current draw in my home, I have measured the AC from about 123V on low consumption times/days to as low as 115V on a day when air conditioners would be one. I'm sure if I repeated with my AC on it would be a volt or 2 lower. Almost exactly as you described.
@@ElectromagneticVideos Well, they don't give a Masters License to anyone man! 😜 That video was super cool, I've repaired cables that looked similar, but not a bad as that, and always wondered how spectacular the actual failure was.
Thanks for the demonstration!
I was also thinking about the fact that you used a welder, which produces pulsed direct current. Line voltage in a home is alternating current, and there are differences in how those two conduct through metals. DC tends to move electrons through the core of a wire, but AC tends to only move electrons on the surface of a conductor, and this phenomenon is called "Inductive skin effect." This is why stranded cables are used in industrial and commercial applications, they have much more surface area than a single round conductor. I'd like to see how many amps of AC power it takes to achieve the same result. I'm going to have to replicate your project at my shop someday, my curiosity has been more than stimulated 😃
@@CommunityGuidelinez Its actually such an old stick welder that the output is plain old AC! The skin depth for 60Hz in copper is about 8.5mm so for 1.6mm diameter #14 wire I would expect little difference between AC and DC anyway. But for larger industrial cables your absolutely right. I deal with a lot of RF stuff where in the Ghz region the skin depth is in the order of μm. For MHz RF sometimes Litz wire is used - essentially woven stranded so much like you described. By the way - great skin depth description! I hope you try the experiment. If you ever get to remove some 1970s Aluminum 12/2 would be really interesting to see how that holds up to overcurrent. It was used everywhere around here (Ontario, Canada) till houses started to burn down. Not sure how common it was elsewhere.
@@CommunityGuidelinez One more question for you: in RF metal pipe is often used since nothing flows in the center anyway. Is that ever done with high power AC power distribution? Or is stranded enough to mitigate skin depth for even the largest wires?
@@ElectromagneticVideos Thats an AC welder!? Wow I had no idea, that's really interesting, I knew they existed but it didnt cross my mind while watching. That's a great point about the skin depth of 60Hz AC in a small 14 gauge wire, there would likely not be a significant change. I'm in the US and go by the NEC/NFPA 75 code, and as far as our 2020 edition is concerned, stranded high power AC Conductors such as a 750 KCM can mitigate the skin effect. There is an adjustment factor for the conductors that can be determined by dividing AC resistance as listed Chapter 9, Table 9, by the DC resistance as listed in Chapter 9, Table 8. Funny thing is that these formulas were calculated on a specific size and type of cable that was determined in 1966 🤣 (Somewhere back near those tables is an informational note regarding that). Going a little bit outside of the box though, NFPA 780 covers traditional lightning protection system requirements, which I believe one could call "high power application." One of these requirements is that conductors intended to deliver electrical discharge from lightning strikes through a building or house should be a Class 1 copper type, hollow, braided wire. So in a way, yes there are similar applications in high power AC to running RF via metal pipe. Good stuff, thank you for responding with good conversation mate. 👍
The thing I don't like about 14 is that about the time you want to give it one more twist, it breaks off.
No
if your target audience is residential people, its important to note that this is 70 amps with only 1.5 volts. so not really typical to what youll use in your house (lights, outlets, etc...). So definitely dont go thinking you can use number 12 for that dryer or larger appliance that requires number 10. While 12 could probably handle it, its not worth the risk to save 100 bucks at all, and its a good way to fail a home inspection
Even if the 12 gauge wiring would survive 30 amps (it likely would) you would lose enough voltage out of it that your dryer would not function at its best. Theoretically it could increase the amperage draw that the dryer would kick even a 30 amp circuit as well.
great video
Thanks Joe!
That is a fun video to watch.
However, I would caution viewers of this video from assuming that Romex/NM-B wiring has "lots of built in margin" and can safely be pushed beyond its rated ampacity limits. My understanding of the electrical code is that it is acceptable and allowed to bury NM-B wiring under insulation, inside walls and attic spaces. Therefore, it is not uncommon for the wire to experience much higher thermal resistance (compared to being exposed to free air), and consequently much higher temperature rise, for a given current level. For example, fully encasing an NM-B wire inside "R13" rated insulation should theoretically increase the thermal resistance and temperature rise by a factor of approximately 13, compared to having the wire free standing in air.
Since thermal power dissipation per unit length (and therefore temperature rise) is proportional to current squared (ex: P = I^2 * R), encasing the NM-B wire in R13 insulation is probably going to result in a somewhat similar temperature rise to running the wire at 3.6x of the rated current, but in a free air environment. In other words, for 14/2 Romex/NM-B wire, which is normally rated for 15 Amps maximum, when fully encased in R13 insulation, may experience about as much temperature rise as it did in this video, when he was pushing the wire to approximately 50-60 Amps (since 15 * 3.6 = 54A) in free air.
It should also be noted that most electrical related fires probably originate from the electrical connections at the ends of the wires. Thermal cycling from repeated heating/cooling often causes loosening of the screw terminals and other interconnecting devices over time. This is due to the thermal expansion coefficient of the metals, causing them to grow and shrink dimensionally as they heat and cool. The subsequent loosening of the interconnection causes increases in resistance of the connections, which then brings even more heating and more severe subsequent thermal cycling degradation. Additionally, bare copper and brass love to oxidize freely in air, which causes a buildup of oxide layer on the surface of the interfaces, leading to more resistance (and therefore much higher heating) over time.
Ideally, manufacturers of wire interconnects would get their act together and start making better quality connectors, which have high safety margin, redundancy of contacts and retention mechanisms, along with active strong spring retention force, rather than single fixed screw/bolt terminal connections, which often loosen over time due to thermal cycling.
What a fabulous summary of all the concerns and considerations! Thanks for taking the time to write it. Your point regarding the effects of insulation: Assuming I have time, I am planning to do a similar informal test of 14/2 in an insulated wall section tomorrow. It may be a less dramatic video but will be interesting to see what happens.
I don't buy how hot type NM-B cable can get inside a R13 insulation. When they switched from NM cable in early 1980's the type TW insulation was only good for 60 degrees C. Type MN-B has type THWN insulation and rated for 75 degrees C . Have removed thousands of feet of mostly older type NM cable from homes & businesses and never came across signs of overheating on cable jacket and the individual conductor insulation. Now that the NEC requires all screws & bolts used to secure wires must be done with a torque driver or torque wrench greatly improving reliability. At an IAEI continuing class the instructor told us that UL went around the country and rounded up hundreds if not thousands of existing device and took them back to test facility to check for proper torquing. Think less then 35% had the proper torque , 20 % excessive torque and remainder too low torque. Told us that over torquing is just as bad as not enough torque. Out of they over 100 attendees that night less then 10% sorry to say owned a torque driver. Before retiring I worked at a rich fortune 500 company who refused to purchase torque drivers, IR camera & circuit tracers.
@@JohnThomas-lq5qp That survey of devices where only 1/3 were correctly torqued is telling. Would be interesting to know how many of them had signs of problems as a result. When you started, I'm guessing torque to a spec was not a thing, other than perhaps really hi powered stuff. I wonder when it started becoming common if not required.
@@JohnThomas-lq5qp you never came across overheated jackets on old NM wiring? Really. I find this fascinating because I have seen it quite a bit. I've even seen it in my old home (built early 1970s) and had to replace it. All the NM was in attic and experienced very high heat for decades plus current draw from kitchen appliances.
@@theelite1x721987 I started out doing residential work first few years then after 15 years seldom did any residential work due to fortunate enough to get tons of commercial work. Myself and another 10th grade industrial shop Vo Tech student rewired a 3 story row house by our selves. Took 250 man hours to rip up floor boards, chisel out paths in plaster over brick walls, etc. Did a lot of machine shops, tool & die shops and injection molding plants but would do work in owners, friends & relative homes. Even was lucky enough to do some electrical work in a 300 year old Quaker meeting house, newspaper, hospital and some 200 year old homes. I upgraded at least 30 or 40 old row houses that only had a 30 amp 120 volt service and they always had deteriorating cloth over rubber insulation. I would often have my helper strip a couple of feet of old Romex to tie up extension cords and even then can not recall seeing either the outside jacket or the black or white insulation showing signs of overheating. Heard one of the reasons they switched from 60 degree C type NM Romex to the far superior 75 degree C type NM-B cable back in the early 1980's was due to the NM deteriorating in attics of homes in the south. Most old homes up north had very few wires in the attics. Most were just for bedroom & attic luminares. At one of my post I mentioned that while attending an IAEI continuing education class the brilliant guy from UL labs told us that UL collected old maybe hundreds if not over a thousand samples of Type AC ( BX ) & NM cables from all across the country and did extensive testing on them. Old clothes over rubber insulation in old AC cable failed think he said it was the Megger test along with some others. The thermoplastic ( always looked like TW insulation to me ) on type NM cables were in fair to good shape.Often came across burnt wires due to loose screw on cheap receptacles. Maybe only an inch or two of insulation was burnt. Came across a burnt ground wire the entire length of a 50' 10/4 cord that feed a portable welder. Somebody used a very long lug to connect the ground output from the generator that was firmly touching the welding case and the ground stinger had most of the fine wires broken off and a worn out stinger clamp that did not attach tight to anything causing most of the 150 Amps or so to be carried by the 30 amp #10 guage cord. Only time I came across a long cord that was smoking it's entire length.
My old 1956 house used 15 gauge wire with black woven insulation. Would be interesting to see how much that would take until flames. A few of the breakers were 20 amps and it hadn't burned down.
@Kelly Harbeson 14 gauge wire is far from rarely used. It's the standard wire for residential homes. At least around here. 12 wire is for 20 amp circuits where required, like bathrooms and kitchens. When someone at work tells me to start pulling wires, I reach for the 14/2 unless told otherwise.
There are plenty of limited current circuits in commercial work, and wether you're using THHN in FMC or MC in commercial, or Romex for residential, 14 gauge wire is 14 gauge wire. However, you're right, you really hardly ever use 14 in commercial.
How many blown 15 & 20A fuses were replaced with 30A?
@@fredmauck6934 100% this. My parents house has what appears to be a 500A main panel because they are all 30-40A fuses. Even with the oversized fuses the air conditioner will trip the fuse if the microwave is already on.
@Kelly Harbeson I don't know where you live, but here where I live everything but the kitchen is 14 gauge. The kitchen obviously needs more capacity so it gets 12 gauge. Some people don't like handing 12 gauge( harder to bend and also to manipulate in the boxes.
Great video !
Thank! Appreciate it!
In a dead-short situation at 120 VAC without some sort of current control (like a fuse or breaker) I would imagine the insulation is going to melt and burn within seconds, and the copper might melt too. It's not easy to predict what could happen in a real-life situation where even higher voltages may be present, like a dryer (240 vac) or a stove. Another UA-camr (sadly, who has not posted for a long time) Photonic Induction has demonstrated many types of destructive tests on all sorts of things. Thanks for the demo. I appreciate the information.
Appreciate the comment - glad you liked the video. I would think that without a breaker (or more likely a failed breaker) you would probably have almost an explosive vaporization of the copper. An industrial electrician I know told me how at a nearby plant a large high current bus vaporized when something went wrong. Thankfully nobody was nearby but apparently the destruction was amazing.
Unfortunately welders (my high current source) have current limiting by design. If I ever come across a large conventional transformer that is suitable, it might be interesting to try some sort of destructive test - outside safely away from everything of course!
Loser. Every country has standards bodies. How the F do you think they come to those standards? Destructive testing is one of the many tests. But nooo just because you don't see it on youtube it doesn't exist.
@@ElectromagneticVideos I have seen a couple of feet of single 12-gauge stranded wire on a tester which was set for 12 volts and had a maximum capacity of about 20,000 amps. The wire was bolted between two buss bars used for large circuit breaker testing. When energized, the wire whistled like a bottle rocket and molten copper came shooting out the ends of the class E Teflon insulation. It was all over in about 2 seconds.
@@solarfluxman8810 That must have been spectacular - I would have been thrilled to have seen that test. Its always amazing to see stuff outside of our everyday experience.
The whistling - there was some of that when I did my small scale version of the experiment on some old extension cords with the vaporizing plastic next to the wire escaping as jets. In your case I wonder if it was the actual copper vapor - how incredible. I wonder if it would have been any different if the wire was solid?
Fire is caused because of temperature, not current. So, you should repeat this test but with the cable inside a conduit, with the maximun amount of cables inside the conduit permited by regulations, and with those other cables at their maximum current permited by regulations. That way the temperature inside the conduit will be higher than in your test. The current to start a fire will be much, much lower.
Edit: the conduit and the maximum amount of cables inside the conduit depends on where you install the conduit. There are regulations for conduits inside wood walls, brick walls, air, ceiling, soil, etc., because the heat transfer to the surroundings depends on the material of the surroundings. You should repeat your test following regulations. The current will be much, much, much lower.
NEC says you can't put wire with sheathing in conduit. Also a cable typically is a multi-wire strand which can't go in conduit. Just insulated wire. But I don't know where you are.
i did a similar test with new wire to K&T wiring, and it actually failed in order from new to old, though the K&T never failed. it took 90 A never failing (it did get very hot, and oozed rubber out of the cloth)
K&T generally is so far apart that it is considered 1 wire suspended in air, and can dissipate more heat into the surrounding air than the two wires adjacent to each other inside the sheath shown here. It's all about if the wire can dissipate enough heat to avoid burning the insulation.
@@glenndoiron9317 yes, that's why it can be used at somewhat higher currents for a smaller wire size.
90A! Wow. Its held by ceramic insulators, right - they didnt crack when it got hot? I had heard it was great as long as it didnt get messed up by modern upgrades.
@@ElectromagneticVideos didn't crack or anything, and it didn't even get that hot, i could put my hand on the wire, the 1940's "Romex" style wire held up very well too, until the outer insulation cooked til' it became conductive carbon and started glowing. Yes, it is fantastic so long as it is not covered by insulation and doesn't get over loaded by dangerous modern additions, usually by homeowners that do not know what they're doing. i have actually wired one of my storage shed's with it, and used an 1800's fuse board that i built myself. works fantastic. I'll one day do a video on it
@@gtb81. Incredible that did vintage setup like that! I hope you video it - I just subscribed to your channel so I dont miss it. Just watched the vintage lightbulb video!
A good splice on wire is created by mechanically joining the wire, solid or stranded. The 'wire nut' is just there to replace the insulation if the wires are properly twisted together first. 3M Red/Yellows are my favorites, but I never rely on them to make the splice. Strip, pinch and twist, then cap the splice with a good wire nut.
The wire nut does twist as well, and bites on to the softer copper. There are arguments both ways as which is better.
It says not to twist first
@AgentOffice I've only been an electrician for 40 years. Splices that are twisted tight first then capped do not come apart. Just write nutted? Those are the fails that result in call backs to fix.
Few years back in my HUD used home...it got cold day after Tday....
I didn't want to fiddle with furnace..
Connected space heater....
Went to bed and fell asleep...at 7 pm
Heard sounds in crawl space...
Smelt faint odor of nasty burnt wood
Woke up 1 am
Walked ouside...saw like fog and smoke down the street...thought some crazy neighbor is buring crates or nasty wood...
Went back to bed...
Could hardly sleep....and thought i heard rats in crawl space...
Was woken by busybody....Your house is on fire...
Barely woke up...was tired...looked at roof vents...smoke billowed out...
Firetruck arrived 8 minutes...put fire out in no time
Tore out drywall..
Previous owners installed ceiling fan and used about 6 pairs of wire nut on
various pieces of 14-3 and flat like gauge 16....they splice in...
The wire glowed red hot.?..burned bottom boards of three trusses of about 20 feet of 2×4 all night
The heater was set on med..
Probably drew 600 watts..
The 25 amp breaker never tripped. Later it was tested...and found not defective...that was replaced later when moved back in
The insulation being thick...like 9" of vermiculite looking pellets...held the smoking 2x4 truss in sort of smoothed state
The house never caught on fire...
My smoke alarm never went off. No smoke was ever seen inside the house....
I so lucky the house and I didnt burn down....
And i remembered to pay insurance....
$67K to fix...
I think the cycling and age of the wire nuts....caused a high resistance....and they sliced it with what looked like odd pieces of extention cord...
Some pieces were 14 gauge bunrt to the copper...
So did the wood coals just burn outward...and then melt the insulation....?
I have no idea
What a story - lucky the house didnt burn and no one was hurt . #67K - ouch!
It sounds like the lack of air circulation - maybe the result of this insulation - prevented a raging fire. If you haven't seen the videos I did following this one of wire in walls take a look. The insulation did seem to keep things form bursting into flames, but also lowered the max current before the wire insulation melted. In some it was almost like you described with smoke creeping out of cracks etc in the wall. And charring where the cable went though the 2x4s.
Very good experiment. One thing I wished you would have done is actually measure the temperature of the wire while you are cranking up the current.
Glad you like it - your not the only one who said that about measuring temperature. When I did it I just thought it would fun to see how much current #14 wire could handle beyond the rated 15A. Never expected the video to get this much attention. I have ordered a thermal prob so may some temp measurements in the future.
Would like to see this test at a constant 120vac reference. With the division of volts and amps you could run thousands of amps at a minute voltage. Show the limit in real world situations at 120v just nit picking, none the less interesting experiment 👍
Ohms law prohibits this unless you put a load in the circuit. Normally current is controlled by the load with a constant 120vac. In this demo there is no load (very small load of the wire) so the current is actually controlled by the voltage. The voltage drop of the wire is a factor of the wire's internal load. In a house the current is controlled by the load.
This is why I ran 12/2 instead of 14/2 on the 15 amp breakers. Rather trip a breaker than burn down the house.
Completely agree - If I was building a new house I'd sure do the same!
I'm not surprised the wire nut didn't heat up appreciably. It really isn't carrying any current. Since the connection is actually the twisted wires, the wire nut serves only as an insulator.
Yes! I'm sure minimal current goes through the thread spring in the nut compared to the wire to wire connection.
wire currant rating has nothing to do, directly, with heat. its all about the voltage drop due to resistance. though you are showing the said voltage drop, a 50 foot wire would be, well, about 50 time grater than your measuring...
also agree with other comments about twisting wires before a wire nut. there is no code to do so. also if you have to take it apart for testing you will need to cut the twisted part off every time as the twisted parts are physically compromised.
The current (amperage) has everything do with heat. Without current no heat can occur. That's why when the Amperage was increased the wire began to heat up and even melt the insulation. Every electrician I've talked to (being an electrician myself) has agreed with the statement, "that when you think of amperage, think of heat. The more amperage you have the greater the heat." So the insulation on conductors isn't just about voltage, but it's rated for a certain amount of heat it can handle before malfunction. This video was somewhat based on that theory, but no temperature was given to help correlate the temperature to current.
The other factor is based on load for sizing wire. And load is correlated to current. As an electrician when someone wants for an example a spa I need to know the Amperage to properly size the wire, because the voltage will always be the same, 120/240 coming from the sub-panel. And a to small wire would burn up under the load or amperage needed
@@TheForgottenMan270 Exactly, now tell this reviewer what every electrician worth their salt does to a wire prior to adding the wire nut and the wire nut package advises electricians to pre twist the wires prior to adding the wire nut.
Wire nuts are not meant to creat a solid connection, they ware meant to protect the open wires like the insulation does.
I have attended numerous demonstrations and seminars by most major wire nut manufacturers (Ideal, 3M, Wago, etc) and they all say that if you install the wire nut properly, there is no need and no advantage to pre-twisting the wires. In fact, at least one of them indicated that pre-twisting actually has a negative effect on the quality of the connection. Pre-twisting is an old skool method that is no longer necessary.
For what it's worth my dad always taught me to have a good mechanical connection before wire nut or before soldering or before whatever always have a good mechanical connection first!!
Mechanical connection prior to the wire nut is in the nec code book
Fun demonstration, reinforces my feeling that conduit is better than NMC
Real electricians Pretwist
I dont think you can beat a solid metal conduit but I assume it is cost prohibitive for most residences? I'm certainly convinced of pretwisting!
I learned that at 120v, the amps are as follows: #10 wire, 30A, #12 wire, 20A and #14 wire at 15A.
Yes thats it for typical house wiring situations.
Best most reliable connection is to strip wires about 7/8" then pretwist using long linesmen pliers, trim ends of wire even, install wire nut, twist with linesmen pliers until at least one full turn of insulation , Tape with a few wraps if quality tape.
You know, its been ages since I have seen tape around the bottom of a wire nut!
@@ElectromagneticVideos Started out in a large slaughterhouse that between all the vibrating crushers, vibrating screens, high speed centrifuges and nightly high pressure wash down had to tape every wire nut. Opened up junction boxes that had 4" of water and energized 240 volt submerged well taped wire nuts that still worked. If not taped would have grounded out. Also always taped every device ( switches & receptacles ). Can never remember ever having a wire come loose on a screw that had a few wraps if quality electrical tape. Pays to go the extra mile.
@@JohnThomas-lq5qp That must have been interesting. I am amazed that wire nuts did so well in such a wet environment even with careful taping like that. Equally impressive surviving longer term vibration. I once had to vibration certify an embedded device - it was staggering how quite mild vibration will eat through insulation or anything else that was rubbing over a few days. You certainly convinced me that taping a wire nut is the thing to do. By the way - the best thing about this video for me has been comments like yours. So interesting to hear things like that!
Wire nuts are theoretically ideal, but in practice are error prone, especially for casual, careless, or hurried installers, or when combining dissimilar wires (such as 14-2 solid to a very flimsy stranded wire for a lighting fixture).
And while wire nuts measure as the least resistive compared to push in and lever couplers, the amount of resistive load is not high enough to make a difference for safety or for efficiency, while lacking the clear see through body that allows for easy confirmation of proper wire insulation stripping distance and fully inserted and secured wire that prevents loose wires (shorts or disconnection) and the very real risk of fire starting arcing.
The fact that the push in and lever couplers are faster (time is money) and easily reconfigurable more than make up for the minor increase in cost, a no brainer for anyone that isn't a technophobe or a stubborn "this is how I've always done it" luddite.
Thats why we pull test them before we move on.......the only ones doing this are homeowners and badly trained apprentices.
@@SuperChad1313 yes, with training and vigilance you can use wire nuts just fine, but it's not a perfect world and humans most definitely are not perfect, even professionals, so it remains that wire nuts are now an inferior out dated product where widely available affordable alternatives exist that are better suited to the purpose, with little redeeming qualities to wire nuts beyond industry inertia and reluctance to change.
From an engineer's standpoint it all makes perfect sense. But then I need a special wago for 2 wire connections, one for 3 wire connections, one for 4 wire connections. Wire nuts are more compact and versatile at a fraction of the cost. I keep a few wagos on the truck for certain situations, but I use them sparingly.
Good demo as long as one remembers that it is done in open air not surrounded by isolation, or installed in an attic where the tempertures may be as hot as 150 degrees in the day time.
Exactly! Did a bunch like that. Take a look at this one: ua-cam.com/video/4k0xLiokNsc/v-deo.html
Rated at 15 amps, which is about 20% less than what it can really handle. There are amp ratings PER HOUR for every wire we can use.
I think appliances are rated for 1250 watts or about 1/2 of what the wire can really handle.
A large toaster.
This was an interesting video of how to destroy a cable.
Just a thought. You are giving the impression that it takes 50 to 60 amps before the conductor insulation is damaged. This is not correct! The insulation on the copper is rated at 90C or 194F. Once the copper goes over that temperature, the insulation starts deteriorating. So, over time being exposed to higher temperatures, the insulation will fail and a short circuit will happen. Also, a ampacity rating means it can be utilized at that amount of amps continuously and not damage the insulation. Not as you suggested. Most breakers however are not continuously rated at their size. They are rated at 80%.
I think you miss the point of the video. This is not "to destroy" the wire or he just crank it up to 100 to see it get destroy right away.
This video showing the limit that wire can handle.
And yes all the usage rating is set before reaching the deterioration limit.
Yes - I really just thought it would be interesting to very crudely see how big the safety margin was between the rated 15A and when it really melted and failed.
In an actual installation, the wire would be conducting heat away from the device terminals it is connected to adding to the heat load of the conductor, but still a nice demonstration.
The way you touch the wire is spine tingling, good luck
It not as scary as it looks! Because the end is shorted there are only a few volts needed across the conductors to push those levels of current though and generate the restive heating effects. I wouldn't be touching them if it was live 120V!
Just throwing this out there, I've been in construction for 15 years, and I've never seen an electrician pre-twist the conductors, before putting on a wire nut. I'm not an electrician, but I have quite a few friends that are, and that just doesn't happen on a typical commercial jobsite.
There was another comment (that I cant find now) from an electrician saying he was specifically taught not to twist them to make it easier to change later (I'm paraphrasing). My comment was maybe it is a regional/local preference one way or the other. I'm in Ontario, Canada and most houses I have lived in (except one) twisting seemed to be the way it was done. Course that's a very small sample set - way smaller than what you would have seen over 16 years in the business. So maybe not twisting is more common.
I work construction and most electricians pre twist as it’s a more solid connection, GC must go for the lowest bid if you rarely see it in commercial
@@Nick-bh1fy That's an interesting comment. I actually did a stress test in another video where I massively overloaded a twisted and untwisted connection and the twisted one was in surprisingly good after 270 Amps. Untwisted not so good, which really supports what you said. Its here if you are interested: ua-cam.com/video/Y-2LmKlQW2A/v-deo.html
@@ElectromagneticVideos the way I was taught was the marrette is only there to insulate the connection and not act as a physical bonding connection between multiple conductors. I strip wires slightly longer, twist from the end and cut off the copper that has been nicked and you’ll have a connection that won’t come apart.
@@Nick-bh1fy Sounds like a real quality way to do it. The wire spring thing in the standard marr type connector really seems quite flimsy, particularly with the softer plastic used today. The old black ones with much more rigid plastic probably could exert more force on the wires, but even then I'll bet your technique would produce a much better connection.
run this at 120v as intended (or 600 if you read the rating) and see how many amps you get. 1500 watt heater runs at 11A-12A at 120V. i would almost guarantee if you use this for a dryer(30A) there would be a fire in a short time. am i not getting some point to amps here watts dont mean anything. all it is is volts x amps = watts. 50 watts is essentially a dim incandescent light bulb
Watts are important because you can measure heater output in watts. 50 watts for an incandescent bulb is not a lot, but three feet of cable inside your wall pumping out 50 watts of heat sure is.
Great experiment! From now on, I'll just use 14 AWG for all my 50 amp garage circuits. 🤣
Be sure to post a video - I'm sure the garage catching fire will get more views than this video :)
Thank you for the sharing.
Your welcome! Got to ask about your name - are involved with Rubidium frequency references? I developed a product using one years ago.
I'd like to see it under 110vac with increasing current. As it stands, 70 amps at 1.47vac (that's what I think that I saw on the meter) is ≈ 103 watts. Under nominal conditions (110vac and 15 amps) it should be fine up to 1650 watts. So this isn't a proper test.
15 gauge? I have never heard of that for AC wiring! I had heard that knob an tube was thinner wire - I wonder if know and tube was 15 gauge. Many the woven insulation was more able to handle higher temperatures than soft plastics?
Voltage is irrelevant to ampacity. Regional high tension lines are limited to 500 amps due to wire size. To get more VA or wattage if your power is 1 they raise the voltage to many thousands. The limit then becomes the arc distance.
The setup he has is actually dissipating 103 watts. Very different than being able to carry safely enough electricity for an appliance to be able to dissipate 1650 watts.
That meter was only really measuring the drop across the romex cable, not what was trying to be supplied. Supplying this test wire with a 110v source would yield a roughly similar voltage drop as this ~10-50V source as it's a near dead short. Amps is amps, voltage is largely irrelevant in a short circuit type test such as this. Well, to a certain point where arcing and insulation breakdown comes into play.
That 1650 watts goes to the device it's powering not the wire. A wire will fail at the same current regardless of voltage.
Actual professional here. Do not pre twist your wire before installing wire nuts it's a waste of time and most wier nut manufacturers specifically say not to do it.
Wire nuts perform two functions -- they're supposed to ensure good electrical connection and also prevent shorts due to exposed conductors. While pre-twisting wires will secure the electrical connection, it can leave the nut itself less than snugly attached. I noticed quite a few turns in screwing on the connector, so it may be that it was indeed fastened well enough to escape loosening during expected conditions. The temptation is, when the wires are already twisted together, to quit applying the nut to said connection before it's truly secure!
Very good point. With pre-twisting one probably should take extra care to make sure the wire nut is on securely.
Agreed. I was taught to NOT twist wires together. That is the marette’s job.
Plus you twist the marette until the wires are twisted. Until then it isn’t tight enough.
It would be interesting to see if it did the same thing at lower current with more volts
The voltage here is along the wire - even at high currents - which is what produces the heat and is the same as what would happen in a real overloaded circuit. If the voltage between the wires was typical line voltage as you suggest (120 or 240V) the only difference would be when the insulation melts or chars to the point when the wires touch and short, we would have a massive over current similar what is shown at the end of the video. I would need a much more elaborate setup to do that safely so unfortunately I cant demo that right now.
Hi Grill Master, voltage and current are not independent. Think of voltage as the pressure that causes the current to flow. Apply a higher voltage (more pressure) and more current will flow. It's just like a water faucet where if you increase the water pressure you will have a higher flow rate of water.
@@wd8dsb Wonderfully clear explanation!
@@wd8dsb and since in a real world scenario, house current is typically used at a higher flow rate; ergo, this experiment is invalidated and the results should be viewed as inaccurate... In relation to real world applications, that is.
I strongly disagree with this demonstration. #14 AWG wire cannot handle 40 A at 120 or 240 Volts. #14 is rated for 15 A at 120/240 V, but only for 80% duty cycle (80% Duration ON with 20% duration OFF in 5 minute increments). All electrical will generate heat. For anything to work, there must be sufficient capability to dissipate the heat, or limit the current to prevent heat generation to the point of destruction. Even with lower voltage (12 to 80 V) driving a stepper motor which has 100% constant on, I will only use #14 AWG wire as 12 Ampere constant on.
I agree. His title was how many amps but no mention of
Volts. So I’ll give him that. But 60 amps at 120v or higher that wire would be glowing. 60 amps at 2 volts is only 120 watts. Vs 7200 watts at 120v. What I don’t like is if some homeowner or handy person who doesn’t understand electrical principles might think they could run 14/2 for say their electric water heater or something with a high current and it will fry. I’d like to see this with a high voltage.
The voltage reading was the voltage drop across the wire with NO LOAD. This was a current control source, not a voltage control source. If you dead short any wire with 120V ac you will certainly get a MUCH MUCH higher than 40 amp current. Like maybe 400-4000 amps. That's why a dead short blows the breaker so fast and throws hot melted metal in your face if you accidentally touch wires in a box. Current control is not generally used so most people don't understand it. We are mostly used to voltage control.
Point being, you will never get 40A at 120V across a dead short. You'd have to have a load to do that. If you put a load (like a light bulb) and it had just the right resistance to make 40 amps at 120V, then the result would be exactly the same as what this video shows. It's the amps the fry it, not the volts.
@@hastypete2 thank you for the the reply I think I may try this experiment. I understand yes. That wire would explode. I’d like to see if that is in fact the case in real world scenario. I can run 14 on a 50 amp breaker powering a heating element out of an air handler.
You missed the point.... 14 gauge is rated to SAFELY be used in a 15 amp circuit.... But you are wrong.... 14 gauge can handle 100 amp in some situations..... He was looking for the failure point in HIS situation.
NEC rates 14 awg NM 15 amp at 120 volts . That's a power rating. Test it at a millionth of a volt and you'll get a bunch of amps before it gets 🔥. It's all about the watts. Run your electric water heater on 120 volts and try to take a hot shower.
hi,
can i savely operate a 24V COB LED strip on 20-22AWG wires?
The AC adapter puts out 24V 1,5A.
The lenght of the wire is about 2 meter long. Ive cutted 6 pieces of 85 cm The COB Led Strip in paralel connection to it.
Is this save or can it be that the wire starts to melt or burn?
Thanks
Your right to be concerned since it is the current (not voltage) that heats the wire. I just looked up the current rating of AWG 22 which ranges from 0.9A to 7A depending on situation. The AC adapter you have is rated at 1.5A but usually something like that can put out more current at least for a while. What you really need to know is how much current the COB Led strips use. You will have to measure it unless the specs tell you how much current each piece draws. Multiply the current for each piece by 6 (you have 6 pieces). If that total current is more than 1.5A you need a bigger AC adapter (or use less pieces).
As far as wire goes, if the total current is less than 0.9 you are fine. If its above, consider a thicker wire to be perfectly safe!
@@gaboaaa23 It says 9W in the specs which means it uses about 0.4A at 24V. If the specs are right, your fine - but you can never be too sure of specs on Amazon. If you dont have a multi-meter to measure the current, leave the lights on for 15 minutes and then feel the wire. If it is at all warm or the insulation seems soft, use a thicker wire.
@@ElectromagneticVideos ok i had the light on for about half an hour. No warmness on the wires or any suspicious.
The ac adapter gow warm slightly. But only hand warm on even less.
The light will only go on if someone goes in front of the glas shelf. And turns off after 1,5 minute. Sos you say it should be fine right?
I have a multimeter. How can i messure the current? I knwo how to messure the "volts" but the current? On which sign i have to switch the multimeter?
Thanks
@@gaboaaa23 You probably OK! For amps look for a setting marked A or mA and like the V setting, AC or DC options - choose the DC one. You have to put the meter leads in series with one of the wires to the light. ie between the power supply and the lamp, not across the two wires like you do for volts or you will burn out the meter. If your not sure and want to measure current maybe ask a friend or neighbor with a bit more experience withe electrical stuff.
@@ElectromagneticVideos i see! Thanks I will call some friend who has some know how on metering. Thanks for your help!
Hi...it matters when I charge the laptop with a different charger that has 2 amps more.. (the original one has 20 w 4 amp, and these 20 w 6 amp)...the battery is defective and I keep it in the laptop just to not turn off the laptop suddenly when the power goes out...I tried with a charger with 3 amps but the laptop its work slowly
The wire is rated for 120V@15 amps. That is around 1800 watts. Your set up is wrong for measuring voltage. The welder at 15-20 amps should still be pushing 20-25 volts or in that ball park. Your grounding clamp should not be touching the ground. My vacuum cleaner pulling 15 amps can get a lot warmer than your set up at 30 amps. Instead of twisting the ends together you need to connect them to a dummy load. Shorting them out is not really a valid test to show how wiring reacts when electricity flows through it.
The cable is probably rated for 600V (this is the insulation rating), so it could theoretically carry 600V*15A = 9kW of power (that is not the same as how much power the cable itself will dissipate as heat). His test setup is fine; he is measuring the voltage drop across the cable which shows him how much power the cable itself is dissipating as heat due to its finite resistance. If the grounding clamp was not connected to ground, there would be no current flow. Where else would it be connected to? The cable can't tell the difference between your vacuum pulling 15A and his test setup pushing 15A through the cable. It all essentially "looks" the same to the cable (the voltage drop would be the same across the cable).
The welder may be designed to operate at those voltages and currents in normal operation, but with it's output shorted with a short length of wire like this it will fail. Ohms law says that the voltage will be the current in amperes multiplied by the resistance in ohms. No exceptions. Your vacuum cleaner gets warmer at 15 amps because the voltage is 300 times higher. Watts is voltage multiplied by current.
@@david672orford Neither the cable nor the vacuum are dissipating 1800 watts as heat. The wire is dissipating much less because its resistance is much lower. The video is demonstrating the amount of power that the cable itself dissipates. The vacuum might heat up, sure, but the majority of the power is being used to create the vacuum, not heat it. Since you're aware what Ohm's Law is, you would have to agree that the cable can't "see" the difference between the the test setup in this video and the vacuum example. With 15A flowing through the cable (in this test setup or the vacuum), the voltage drop across the cable is the same.
@@stuckbreaker8586 Yes, I agree with you completely. The test rig shown in this video produces correct results. Those who keep bringing up how many watts this cable could deliver to a load at 120 volts are confused about what is being measured in watts in this video. And yes, only part of the 1800 watts remains behind in the vacuum cleaner as heat, but it is easily far more than the 21.45 watts which this cable dissipates at 30 amps. So Bryan Rocker should not be surprised that the vacuum cleaner gets warmer.
@@david672orford Agreed, I misunderstood your previous comment and thought you said the test setup was a failure.
Just curious. Some questions:
How long was that 14/2 cable?
What was the waveform of your AC? (The output of your welder)
Are your meters RMS or averaging?
I think it was 3 or 4 feet. You know, it would be interesting to put a scope on the welder and see - I would expect at the low current levels it would a fair sinusoid since I am powering the welder at abouy 1/4 of its normal 240V so I doubt any of the core is saturating. The meters - they are cheat hardware store ones. I'll have to see if they are true RMS. It wasnt meant to be any sort of calibrated test!
I wonder if AC vs DC would make any difference in this setup?
thanks for the video. i love, correction i must know and see the limits of things that i am playing with. it drives everyone around me nuts. but when things get complicated they know who to call
Your welcome! Totally agree - there is nothing like seeing a real example of something rather than just looking at theory (at least whenever possible!).
Thanks very informative
Glad you liked it!