I've heard many folks on this forum say that if you leave a power cord coiled up or don't roll it out all the way, it will heat up and could eventually catch fire.This seems extraordinary to me since 1) there just isn't that much current running through these cables and 2) The wires are insulated and I would think inductors require much closer spacing of wires and a lot more of them. and 3) I've never noticed my coiled wires getting very warm at all and 4) There's nothing about this hazard in the owner's manual.So what's the truth here? Am I taking dangerous risks or can I sleep in peace?On Edit: The responses to this post have been terrific. After reading all of them I've concluded that 1) there is no inductive heating of the wires as you might have under other circumstances and 2) there is always resistive heating of wires when you pass a current through them.The general consensus of all the responses is that while there is no inductive heating caused by coiled wires, there could be a small amount of resistive heating in the wires. However, This resistive heating will probably be about 45-70 watts depending on how much power is being used in the coach. That amount of heating is unlikely to ever cause a fire hazard. Nothing to worry about with standard RV power cords. So coil away in peace.The bigger fear would be in using small gauge extension cords and coiling them or gathering them or covering them in carpet and trapping the heat. Small gauge cords will have more resistance and, hence, more heating which could accumulate and cause problems.Thank you to all who posted.

maybe if you tie a knot in it, it will get hot.I don't think so.

Coiled electric cords will heat up. I've never seen one get hot enough to catch fire. I have left mine coiled in the electric bay many times at some campgrounds where the elect post was very close.

It depends...It depends on the size of wire. (smaller wire, more heat)It depends on the number of coils. (more coils, more heat)It depends on the amount of current going through the wires. (more current, more heat)It depends on how long the high current flow lasts (longer time, more heat)If you have 30 amp service, and run the A/C and the microwave and the tv at the same time for an hour or so, maybe the wires will get warm.If you have 50 amp service, you can run everything for a longer time.Personally, I would not worry about it. While it may have happened 50 or 60 years ago, and the story is still going around, I have never heard of it happening recently. If it was truly a hazard, you can bet there would be warnings posted all over the place!

How about XL @ 60 cps. XL equals 2 pi F L Would have to be a pretty tight coil around a core of more than air for much inductive reactance at 60 cps.

If that is possible then all us guy's with automatic cord reels are in trouble.

Do coiled power cords heat up and cause fires? | Good Sam Community

BruceMc
Explorer III
Nov 17, 2015
I spotted what looked like a nice heavy 50' extension cord in the clearance section of a local CW the other day. It was a 15A cord, and the size of the cord made it look like a 10 gauge or possibly a 12. I picked it up and read the info:

"For recreational use only"
and
"16AWG"

I couldn't believe my eyes. I left it on the clearance rack....

Regarding the OP's question, I've seen a coiled cord that melted. The cord was properly sized for the job - a 14 gauge 50'. Problem is, my friend needed a short extension cord for his load of perhaps 10-12 amps, and rather than uncoiling the whole thing, he uncoiled a couple of loops off and plugged it in.
He brought the ramains to me a few days later. It was still tightly wound around the cord rack, never to come apart again.

It happens. Either loosely uncoil it, or go get a cord of the proper length and gauge to do the job.
rhagfo
Explorer III
Nov 17, 2015
holstein13 wrote:
jwmII wrote:
...and you took the bait.
I don't think the guy in the video is stupid. Quite the contrary. I think he is like most campers, uninformed about common dangers and electrical principles.

It's nobody's fault, really. It simply illustrates a problem in society and that is a lack of common sense. Our civilization does not place a high value on science and engineering. I think that's a shame.

The fact that people don't understand basic science scares me. It genuinely scares me. That doesn't make me a bad person, or judgemental, or condescending. It concerns me because well meaning people in the campsite next to me could, unintentionally, set the park on fire. It concerns me because great folks driving on the highway don't understand the risks they take and the physics that could ultimately injure them and affect others on the highway.

I think science is important for the general voting population to understand. There are many questions related to GMO, vaccines, climate change, food and air safety, resource allocation and protections, water preservation, etc. that we, as a society, have an interest in. We elect politicians to represent us and most don't seem to have any basic understanding of science. How can we expect them to make good decisions if they don't understand the basic scientific process related to the issues that confront us?

I'm concerned about people like the guy in the video, not because I'm judging him or think I'm perfect, but because people like him could unintentionally endanger us.

I totally agree lack of common sense, and basic science.

Thinking you can use a really small cable to hook a really big cable and be able to use like normal.
Not induction heating, but too big of current draw on too small of cable! 100' of 16 gauge wire supprised he didn't damage the AC from running with low voltage.
To get a 20 amp rating on a 100' cord it needs to be 10 gauge not the standard 12 gauge.
bigdad1
Explorer
Nov 16, 2015
The simple answer is, yes. Having investigated many fires in 25 years, I've had plenty of flexable cord fires. The problem is not the cords, but in how they are used and abused. As long as they are plugged into current, they can cause a fire. Hidden damage and running under furniture etc, they will get hot and cause a fire.
pianotuna
Nomad III
Nov 12, 2015
Hi,

Get an IR thermometer (Harbor Freight has one for $9).

Set up as you plan to do. Then turn on every load in the Rv. Every five minutes "shoot" the coil to see what the temperature is. After 30 minutes you may have a good idea whether you wish to do this or not.

After I tried this, I decided that coiling was not a good plan--particularly in the "mouse hole".
cmcdar
Explorer
Nov 12, 2015
Some people are just not bright enough to understand many things, BUT they are bright enough to learn from others mistakes.

It seems to me that the guy who used the wrong gauge extension cord made a video to try and help others learn from HIS MISTAKE.

Funny, that the OP asked a simple question and there were several answers NO IT WON'T and several answers YES, IT CAN.

Truth is, like with many things - It all depends.
holstein13
Explorer
Nov 12, 2015
jwmII wrote:
...and you took the bait.
I don't think the guy in the video is stupid. Quite the contrary. I think he is like most campers, uninformed about common dangers and electrical principles.

It's nobody's fault, really. It simply illustrates a problem in society and that is a lack of common sense. Our civilization does not place a high value on science and engineering. I think that's a shame.

The fact that people don't understand basic science scares me. It genuinely scares me. That doesn't make me a bad person, or judgemental, or condescending. It concerns me because well meaning people in the campsite next to me could, unintentionally, set the park on fire. It concerns me because great folks driving on the highway don't understand the risks they take and the physics that could ultimately injure them and affect others on the highway.

I think science is important for the general voting population to understand. There are many questions related to GMO, vaccines, climate change, food and air safety, resource allocation and protections, water preservation, etc. that we, as a society, have an interest in. We elect politicians to represent us and most don't seem to have any basic understanding of science. How can we expect them to make good decisions if they don't understand the basic scientific process related to the issues that confront us?

I'm concerned about people like the guy in the video, not because I'm judging him or think I'm perfect, but because people like him could unintentionally endanger us.
StarkNaked
Explorer II
Nov 12, 2015
holstein13 wrote:
StarkNaked wrote:
Inductive... No. Fire... probably not.

But....... I do have a plastic cord reel that my brother gave me that he overheated by not un-coiling the cord. It has clearly defined melt marks on the inside of the spool where the cord got hot enough to start melting the plastic reel.
Is it safe to assume that the reel melted because the cord got hot from resistance? I would imagine that not uncoiling the hot cord probably exacerbated the problem with poor air flow and a concentration of the heat that had already formed from the high resistance in the power cord. Would you agree?

Exactly! Too much current draw for the size of the extension cord (too small), and no where for the heat (or over heating) to go.

Bottom line... Never use a cord that is undersized for your current draw.
tenbear
Explorer
Nov 12, 2015
SDcampowneroperator wrote:
IAMICHABOD wrote:
amdriven2liv wrote:
Check out this guys electric cord. And don't do this. Check out the comments on his video.

https://www.youtube.com/watch?v=L23d4Eq5pX4

Ya can't fix stupid
Looks to me like the orange cord is a 16 Gauge. With the A/C and other loads in the rig, the amp draw is too much for the cord, not because it was loosely coiled. He had to have had a near 20 amp load in the rig with A/C, converter, fridge etc.. For that load a 12ga. cord is minimum.
The brown down of voltage loss through heating resistance should have tipped him off that something is wrong before it got that bad.
Not stupid, just not knowing. Stupid is the reverse.

Couldn't agree more. :)
SDcampowneroper
Explorer
Nov 12, 2015
IAMICHABOD wrote:
amdriven2liv wrote:
Check out this guys electric cord. And don't do this. Check out the comments on his video.

https://www.youtube.com/watch?v=L23d4Eq5pX4

Ya can't fix stupid
Looks to me like the orange cord is a 16 Gauge. With the A/C and other loads in the rig, the amp draw is too much for the cord, not because it was loosely coiled. He had to have had a near 20 amp load in the rig with A/C, converter, fridge etc.. For that load a 12ga. cord is minimum.
The brown down of voltage loss through heating resistance should have tipped him off that something is wrong before it got that bad.
Not stupid, just not knowing. Stupid is the reverse.
bukhrn
Explorer III
Nov 10, 2015
OK, I didn't have the sound on, as I was listening to something else, but just looking at that, it looks like the orange cord had been run over by a lawn mower. :E I wouldn't plug my electric drill into that !! :S

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Do coiled power cords heat up and cause fires?

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