EEK. What on earth happened to this (link to photo inside) extension cord?

Question

http://flickr.com/photos/kmennie/357726162/

Last night, there was a bad smell -- sweet burnt plastic with a hint of Lemon Pledge -- and I figured it came from the heater that was plugged in to that extension cord.

And switched heaters, running it off the same now-burnt and non-functional cord.

The smell persisted, and the cord worked for several more hours. (It had not only a heater but a small clock plugged in to it.) We did blow a fuse today, and still had no idea it of the extension cord's problems...

What on earth happened? It was plugged in in an area not readily visible. I am, yes, lucky to've not burnt my house down. I am also curious...

Yes. Yes. I know I was being an idiot. Tiny heater. But...

(sigh)

How safe is it to plug anything into that outlet now, do you think?

Answer 1

The picture clearly shows a very light duty cord. A heater needs a heavy duty cord.

Unfortunately, a problem like this is somewhat unlikely to trip the breaker. Instead, it will simply heat up. The results could be disasterous.

A person needs to make sure they use extentions that are rated for the amount of amperage that they are going to use. It also helps to feel the cord and the plug to see if it warm when you smell something getting too hot.

You got very lucky.

P.S. you asked a followup question...It is hard to tell what is under the surface by looking at the outside of the outlet, but in your case, the pattern of the damage tells me that you need to have the wiring of that outlet checked. Actually, wether or not you use it is not the point, it can be dangerous, just sitting there, if the insulation of the wires leading to it are damaged.

Granted, I have only seen one case where the wires were damaged enough to be dangerous, but one case is enough. At the absolute minimum, you should replace the outlet.

The plug is totally fried so the outlet has to have some damage. Have a qualified electrican check the wires and replace the outlet. The outlet may be a DIY job that you can handle, but checking the wires is probably not in your DIY skill set.

As for the answer about a carbon path being created...too much theory, not enough looking at the picture of the actual damage. Look at where the damage is and you will see it was not a carbon path. Also, there is no positive and negative wires in ac, only in dc. In ac they are referred to as hot and neutral.

There is NO way to tell if the wires inside the wall were damaged without looking. They need to be checked. Perhaps when the outlet is replaced, you can see enough to give you confidence. Saying the wires are not damaged without looking is dangerous.

Answer 2

There were a few different things going on there. First of all, the folks who told you that you should have a bigger size cord (a larger wire size...at least #12 awg copper wire) were absolutely correct. Electric heaters can draw up to 15 amps or more, and it is best to NOT use extension cords with them. If you must use an extension cord, NEVER run a heavy load like a heater on a skinny cord....especially a LONG skinny cord. What causes electricity to generate Heat like That is a loose connection. The end of that cord had obviously been damaged somehow, even though it may not have been obvious by looking at it. Sometimes a cord will get stepped on or tripped over, and it will damage the spot where the prongs attach to the wires (inside the cord). If you are running a light load (clock, radio, small lamp, etc.) there will not be enough current flowing to cause any major problems. In this case, since it was a heater (10 to 15 amps), there was enough current to cause it to get hot. Once it started getting hot, it just continued to get hotter and hotter until the cord was fried. You were lucky to notice it before a fire happened! The outlet that it was plugged into may have been part of the problem too. Over time, the contact points inside of the outlets become worn and loose from years of use. This will also create hi-resistance heat problems with a heavy load like a heater, and this is made worse by using too small of an extension cord. HOW TO FIX THIS? 1. Throw out that cord. If you absolutely must use a cord, buy one that is a #12 AWG cord, and Not any Longer than necessary. 2. Check the outlet that the cord was plugged into. If another plug feels loose or goes in easily or does not want to stay in the outlet, Replace that outlet. If there is Any doubt, replace the outlet. This is easy. Turn the power off, and verify that it is off with a voltmeter, volt tester, etc. If you do not have a volt tester, plug a lamp in, and turn it on. Turn off the breaker, and make sure that the lamp is now off. With the power off, remove the old outlet. When installing the new outlet, connect the wires to the screws on the sides of the outlet. The black wires go to the brass or copper colored screws; white wires go to the silver screws: and the bare (or green) wires go to the green screw on the bottom of the outlet. Make sure that the screws are tightend securely. If you have any doubts, get some help from a a qualified electrician or someone who knows how to do it. You should also look carefully at the heater or heater that you were using to see if there is any problems with them. Examine the ends of the cords to see if there was any signs of arcing or burning. Check to see if the cord ends fit snugly in another (good) outlet. Sometimes a loose plug end can be fixed by simply spreading the prongs a bit. I hope that this helps you. If you have more questions, I will try to answer them for you. Good Luck.

Answer 3

the cord on the heater is most likely a larger gauge wire than the extension cord that you had it plugged into. that should have been your first clue, the fact that the burning smell persisted your second clue. didn't they teach you anything at those institutes of higher learning that you went to? or can't you read? after all, most appliances do come with instructions, and the first page or two of warnings about using the appliance. guess you are just lucky that the bath water was hot enough. well before you use the outlet that the extension cord burned up in, you might want to have it looked at by a QUALIFIED person. by the looks of the plug on the cord, it could have sustained some damage. in the mean time do not use that outlet until it has been looked at!! better safe than sorry,huh? good luck.

Answer 4

You have to many things plug into that fuse that is using more amps than the fuse was able to supply and that is why it blew, the picture is telling me that is was a fire waiting to happen. Did you install a bigger fuse? If so you almost started a fire and burnt your place down. If not then the this was a godsend and the heater was pulling a lot of amps and looks like it may have either arching or getting extermely hot. Which would cause this cord to fail, the plug may be damaged also, so have someone check the plug also, it may need to be replaced.

Answer 5

Most space heaters made today draw 15 amps of power typically. Your outlet on the wall is typically 15-20 amps. Therefore your circuit was maxed out. The extra wire in the form of the extension cord lowered the amp capacity of the plug due to it's length. If your breaker or fuse didn't trip in this process I would say you are VERY lucky. Check your panel box, and throw the switches or loosen fuses until you find the outlet that the cord was plugged into. Once found look at the breaker or fuse and determine what amperage it is. It will be on the face of the breaker and on the glass of the fuse. If it is more than fifteen amps get the right one and change it out. The breaker may required an electrician to change it out.

Answer 6

The answer is simple, the cord was not big enough to hold the amperage, it over loaded the cord. For one thing, you should plug a space heater directly into plug if you have to use extension cord use a 12 gage cord the shorter the better, the the longer the cord is the more voltage drop you have. Be & Think Safe.

Your lucky your house didn't burn down.....

Answer 7

Probably the cord was undersized wiresize to start. What then happened is over time the plastic insulation between the negitive and positive wires within the cord broke down due to heat and formed a carbon compound which was conductive.

The cord itself then at some point acted like a long resistance heater and the hotter it got the less resistance the deteroriated plastic insulation provided and eventually the cord self destructed.

Next time go to a hardware store and get a cord that is "oversized" for a heater application it is safer and will last indefenitely.

Answer 8

The burn damage is confined to the immediate area of the plug. The damage looks as if that were where the problem is. When using a heater it is common for the plug and receptacle to get warm. When using an undersized extension cord it is common for the cord to get at least warm, and maybe hot.

The combination of cord heat and plug heat is likely to have raised the temperature of the insulation to its ignition temperature.

For sure the receptacle needs to be replaced.

Buy yourself one of those plug strips, rated to at least 15 amperes, and with a circuit breaker in it. If you ever use the second heater off an extension cord, buy two.

Answer 9

Yes you were lucky and hope you have smoke detectors.

It appears the "draw" by the heater was higher than the cord could handle. So in the future look at the rating of an extension cord and get a very heavy duty one for such a use.

Answer 10

Yes, an indoor extension cord will work outdoors, however if it gets wet and someone gets a shock or there is a fire, your insurance company and you will likely have a very difficult time in court. If you decide to take the risk, don't ever leave an indoor extension cord outdoors overnight....