Melting Stove Cords and Me
March 5, 2012 8:03 AM Subscribe
Our stove's electric cord melted and our electrician says that he thinks it was a fault with the stove itself. When I say the cord melted, it is a 6 inch gooey mess starting in the center of the cord that had heated up to the point where it started to burn through the wall and melted a hole in the gas line. The stove itself was off (oven and burners) and it apparently happened spontaneously. The electrician was, in his words, "shocked your house did not burn down. Be glad you smelled the gas when you did".
My question has two parts going on the electrician's hypothesis:
1) The stove is out of warranty but it is still only 7 years old. Maytag is sending a repair person to asses the problem. Would we have any leg to stand on to ask for money towards a new stove? I doubt it but am hopeful.
2) Who, if anyone, should we notify that there may be an issue with these stoves? I would hate to think that someone else's house might burn down through some sort of faulty wire and we could have let "someone" know. (we are in Georgia).
A bonus question - can anyone think of how this could possibly have happened? It seems pretty odd to us and to the electrician and we cannot think of something that might have made this happen.
You can report it to the Consumer Product Safety Commission here.
posted by TedW at 8:31 AM on March 5, 2012 [2 favorites]
posted by TedW at 8:31 AM on March 5, 2012 [2 favorites]
can anyone think of how this could possibly have happened? It seems pretty odd to us and to the electrician and we cannot think of something that might have made this happen.
Cords will melt like that when either they are carrying too much amperage, or the insulation has a fault, or the actual copper wire has a fault. The first is unlikely as you should have noticed your stove giving off a bunch of heat. The insulation having a fault or the wire being damaged can cause an Arc Fault Failure. Arc faults can occur at very low loadings, the power drawn by the clock is enough, and once established can be self perpetuating slowly growing from unnoticable to melt your wall dangerous.
Usually this sort of cord failure after such a long time in service is caused by mechanical damage. The fault occuring in the center of the cord is some what telling as that is usally where they bend. Have you pulled the stove out in the past few months? Pushing it back may have cracked the insulation or damaged the wiring internally; especially if the cord had been damaged in the past or had a manufacturing defect. The internal insulation can break without the outer sheath being obviously damaged.
As to why it didn't trip the breaker: If it was an Arc Fault failure then a regular breaker won't see it because the average amperage draw is within the rating. Arc Fault detection requires special breakers which rarely are installed for cord connected equipment. If it was regular overloading a breaker isn't an instant reacting device. IE: no 40A breaker holds at 39.9 and trips at 40.1. Often depending on ambient temp a breaker will hold for a while even when overloaded by a significant percentage of it's rated value. depending on chance that over current could be enough to damage the cord over time without ever tripping the breaker.
It never hurts to have a look or even replace a suspect breaker (your average 40A plug in breaker is less than $50 and takes 10 minutes to change) and some panels are notorious for substandard breakers but your Electrician should have informed you if you have one of those types of panels; if only in an attempt to up sell you a new service.
posted by Mitheral at 8:37 AM on March 5, 2012 [5 favorites]
Cords will melt like that when either they are carrying too much amperage, or the insulation has a fault, or the actual copper wire has a fault. The first is unlikely as you should have noticed your stove giving off a bunch of heat. The insulation having a fault or the wire being damaged can cause an Arc Fault Failure. Arc faults can occur at very low loadings, the power drawn by the clock is enough, and once established can be self perpetuating slowly growing from unnoticable to melt your wall dangerous.
Usually this sort of cord failure after such a long time in service is caused by mechanical damage. The fault occuring in the center of the cord is some what telling as that is usally where they bend. Have you pulled the stove out in the past few months? Pushing it back may have cracked the insulation or damaged the wiring internally; especially if the cord had been damaged in the past or had a manufacturing defect. The internal insulation can break without the outer sheath being obviously damaged.
As to why it didn't trip the breaker: If it was an Arc Fault failure then a regular breaker won't see it because the average amperage draw is within the rating. Arc Fault detection requires special breakers which rarely are installed for cord connected equipment. If it was regular overloading a breaker isn't an instant reacting device. IE: no 40A breaker holds at 39.9 and trips at 40.1. Often depending on ambient temp a breaker will hold for a while even when overloaded by a significant percentage of it's rated value. depending on chance that over current could be enough to damage the cord over time without ever tripping the breaker.
It never hurts to have a look or even replace a suspect breaker (your average 40A plug in breaker is less than $50 and takes 10 minutes to change) and some panels are notorious for substandard breakers but your Electrician should have informed you if you have one of those types of panels; if only in an attempt to up sell you a new service.
posted by Mitheral at 8:37 AM on March 5, 2012 [5 favorites]
I suspect the Maytag repair person will replace the cord and ask to keep the gooey mess. After this your stove will probably work fine. I would not touch anything until the Maytag guy appears. If this does happen and the repair guy says all is well, I would ask for something in writing to document some "official" indicated using the stove was safe (this might be tough).
it sounds like a short in the cord. Given your description, I think it would be hard for the stove to initiate the problem - there is probably an internal fuse on the stove which would blow well before you could draw enough current through the cord to cause a fire in the cord.
Was the cord crimped or in anyway moved in recent memory?
posted by NoDef at 8:40 AM on March 5, 2012
it sounds like a short in the cord. Given your description, I think it would be hard for the stove to initiate the problem - there is probably an internal fuse on the stove which would blow well before you could draw enough current through the cord to cause a fire in the cord.
Was the cord crimped or in anyway moved in recent memory?
posted by NoDef at 8:40 AM on March 5, 2012
Response by poster: We have not moved the stove that I know of anytime recently. I know that I have not and cannot imagine my wife doing that.
The Maytag guy will be there tomorrow. The electrician was oddly adamant that we get rid of the stove. We will wait to hear what the appliance guy says tomorrow.
posted by GrumpyMonkey at 8:59 AM on March 5, 2012
The Maytag guy will be there tomorrow. The electrician was oddly adamant that we get rid of the stove. We will wait to hear what the appliance guy says tomorrow.
posted by GrumpyMonkey at 8:59 AM on March 5, 2012
I would suggest that you take about 200 pictures of the gooey mess from every possible angle. Get right up on it and look for anything that may resemble a crack, a dry rot, etc. If you can see wire (should be stranded and big), see if you can see any stresses---wires sticking out, abrasions, nicks, cuts, etc, and photograph them too. Feel free to share those stories with us.
I'm as much concerned that anything could burn a hole THROUGH a gas line as I am the rest of the story. Plastic gas line? Wat?
Interestingly, the other day I finished a temperature controller and was testing it using a water kettle. The power line is a normal, computer-type female plug. After about 15 seconds in "on", I noticed a smell and realized the entire line was smoking---not from the controller to the kettle, but from the controller to the wall. I yanked it and chucked it in the snow before any damage was done, but I couldn't believe that the current draw could be so high that it could smoke a pc cord when the normal, 14 gauge kettle wire was fine. Turns out the cable wasn't UL listed and was NOT at spec, and was completely illegal in the US and shouldn't have been included in whatever package I bought it with. Probably didn't happen with your stove, especially because you had no runaway current issue, but I thought I'd share.
posted by TomMelee at 9:19 AM on March 5, 2012 [1 favorite]
I'm as much concerned that anything could burn a hole THROUGH a gas line as I am the rest of the story. Plastic gas line? Wat?
Interestingly, the other day I finished a temperature controller and was testing it using a water kettle. The power line is a normal, computer-type female plug. After about 15 seconds in "on", I noticed a smell and realized the entire line was smoking---not from the controller to the kettle, but from the controller to the wall. I yanked it and chucked it in the snow before any damage was done, but I couldn't believe that the current draw could be so high that it could smoke a pc cord when the normal, 14 gauge kettle wire was fine. Turns out the cable wasn't UL listed and was NOT at spec, and was completely illegal in the US and shouldn't have been included in whatever package I bought it with. Probably didn't happen with your stove, especially because you had no runaway current issue, but I thought I'd share.
posted by TomMelee at 9:19 AM on March 5, 2012 [1 favorite]
Given what you've said, I find it hard to believe this was anything other than a faulty power cord. If the stove was off (and on/off switches on stoves are about as reliable as electrical products can be made... there's just not much there to fail, really), it has to be the cable's fault... or the junction where it is attached to the stove.
The junction could have a short somehow (grease accumulated, a stray wire, whatever), but then the melt area would be centered on the junction, not the wall. Where does it look the worst?
posted by IAmBroom at 9:36 AM on March 5, 2012
The junction could have a short somehow (grease accumulated, a stray wire, whatever), but then the melt area would be centered on the junction, not the wall. Where does it look the worst?
posted by IAmBroom at 9:36 AM on March 5, 2012
Response by poster: I will post pictures in a bit but the worst area of the melt is right in the center of the cord. No kinks or anything that I can see.
posted by GrumpyMonkey at 10:18 AM on March 5, 2012
posted by GrumpyMonkey at 10:18 AM on March 5, 2012
m as much concerned that anything could burn a hole THROUGH a gas line as I am the rest of the story. Plastic gas line? Wat?
Plastic gas line is popular. Of the other two main stream options copper is horribly expensive (and is more prone to physical damage IMO) and black iron is both expensive and very hard to work with.
I couldn't believe that the current draw could be so high that it could smoke a pc cord when the normal, 14 gauge kettle wire was fine.
Many PC cords are only rated for a few amps. For example the 18AWG STP-2 feeding my laptop is rated for 7 or 10 amps; well under the amperage draw of a typical electric kettle. Type TXF is only rated for 5A.
posted by Mitheral at 10:30 AM on March 5, 2012
Plastic gas line is popular. Of the other two main stream options copper is horribly expensive (and is more prone to physical damage IMO) and black iron is both expensive and very hard to work with.
I couldn't believe that the current draw could be so high that it could smoke a pc cord when the normal, 14 gauge kettle wire was fine.
Many PC cords are only rated for a few amps. For example the 18AWG STP-2 feeding my laptop is rated for 7 or 10 amps; well under the amperage draw of a typical electric kettle. Type TXF is only rated for 5A.
posted by Mitheral at 10:30 AM on March 5, 2012
Mitheral-
I trust you that plastic gas line is very popular, however I do accessible design and contractor hiring as a profession, and where I live, everyone has NG and I have never actually seen anything other than black iron here, even in brand new construction.
Also, this is a very little kettle. I changed the cord for a different, UL listed normal cord (I forget the designation, C3 or something, I believe) and all is well.
posted by TomMelee at 1:41 PM on March 5, 2012
I trust you that plastic gas line is very popular, however I do accessible design and contractor hiring as a profession, and where I live, everyone has NG and I have never actually seen anything other than black iron here, even in brand new construction.
Also, this is a very little kettle. I changed the cord for a different, UL listed normal cord (I forget the designation, C3 or something, I believe) and all is well.
posted by TomMelee at 1:41 PM on March 5, 2012
If it was a metal gas line-- as almost all the one's I've seen have been-- I'd say the cord arced through a crack in the cord insulation to the grounded gas line, and ate a hole in it, rather than melted one, and that the insulation melted not from excessive current, but from the heat of the arc conducted back into the cord by the thick copper conductor, and that the gas escaping blew out the arc without igniting.
If that's what happened--wow!
posted by jamjam at 3:56 PM on March 5, 2012 [1 favorite]
If that's what happened--wow!
posted by jamjam at 3:56 PM on March 5, 2012 [1 favorite]
But don't ask me where that apostrophe came from.
posted by jamjam at 4:01 PM on March 5, 2012 [1 favorite]
posted by jamjam at 4:01 PM on March 5, 2012 [1 favorite]
Response by poster: Pictured are on flickr.
gas line hole
melted cord detail and overview
I was wrong, the melted area is closer to the plug, not the middle.
The gas line is metal.
posted by GrumpyMonkey at 4:19 PM on March 5, 2012
gas line hole
melted cord detail and overview
I was wrong, the melted area is closer to the plug, not the middle.
The gas line is metal.
posted by GrumpyMonkey at 4:19 PM on March 5, 2012
I may have been wrong about the cord being melted by the heat of the arc (I was visualizing a 240V pigtail), but I do think that is a hole burned by an arc in the gas line; if it was a melted hole, the plastic coating on the gas line would have melted and discolored in the area around the hole, and that didn't happen.
But in my hypothesis there should be some kind of flaw in the insulation of the cord at a point where it was crossing the gas line when the whole thing went.
The cord could have heated up and partially melted, then melted the plastic coating on the gas line, then the exposed conductor in the cord could have touched the exposed metal of the gas line, and the resultant arc could have burned that hole in the line.
posted by jamjam at 6:13 PM on March 5, 2012 [1 favorite]
But in my hypothesis there should be some kind of flaw in the insulation of the cord at a point where it was crossing the gas line when the whole thing went.
The cord could have heated up and partially melted, then melted the plastic coating on the gas line, then the exposed conductor in the cord could have touched the exposed metal of the gas line, and the resultant arc could have burned that hole in the line.
posted by jamjam at 6:13 PM on March 5, 2012 [1 favorite]
After looking at the pictures - I agree, you are lucky the house is still standing.
I would definitely get the outlet checked out. Make sure that it is grounded and wired correctly. It would be interesting to see the potential (if any) between the ground terminal of the plug and the gas line.
Is this an older house? Is it possible the outlet could have originally been a 2 prong plug and was replaced to accept grounded plugs in the past - without grounding it correctly?
It might also be useful to mention this to the gas company - I'm pretty sure that gas lines are connected to a common house ground (might be called bonding). If not done correctly, that might have contributed to the problem...
posted by NoDef at 6:14 PM on March 5, 2012
I would definitely get the outlet checked out. Make sure that it is grounded and wired correctly. It would be interesting to see the potential (if any) between the ground terminal of the plug and the gas line.
Is this an older house? Is it possible the outlet could have originally been a 2 prong plug and was replaced to accept grounded plugs in the past - without grounding it correctly?
It might also be useful to mention this to the gas company - I'm pretty sure that gas lines are connected to a common house ground (might be called bonding). If not done correctly, that might have contributed to the problem...
posted by NoDef at 6:14 PM on March 5, 2012
Hypothesis:
1. Ground @ the breaker box is tied into a black iron gas line instead of a water line or ground spike.
2. There is a ground fault somewhere, possibly in the stove plug, possibly in a breaker, possibly somewhere in a wall.
3. Ground fault means there is a small charge on the gas line.
4. Stress on cord from age/excessive heat/rodent damage/defect causes a very small arc.
5. $Profit.
Or just the gas line is grounded for reals, and the line arced to it for whatever reason. I'd be opening my plugs and checking resistance/continuity on those lines.
posted by TomMelee at 6:00 AM on March 6, 2012
1. Ground @ the breaker box is tied into a black iron gas line instead of a water line or ground spike.
2. There is a ground fault somewhere, possibly in the stove plug, possibly in a breaker, possibly somewhere in a wall.
3. Ground fault means there is a small charge on the gas line.
4. Stress on cord from age/excessive heat/rodent damage/defect causes a very small arc.
5. $Profit.
Or just the gas line is grounded for reals, and the line arced to it for whatever reason. I'd be opening my plugs and checking resistance/continuity on those lines.
posted by TomMelee at 6:00 AM on March 6, 2012
Response by poster: Well, Maytag send an appliance repair guy and his comment after going over the stove and the wires was "Holy crap, I have no idea why your house is still standing! Yeah, this is going back the the factory to be disassembled and analyzed." So now we wait to see what, if anything, Maytag will do to help replace the stove.
We will be calling back the electrician and plumber (I assume it is the plumber) to install a new socket and check the gas line grounding.
Yikes...
posted by GrumpyMonkey at 5:34 PM on March 6, 2012 [1 favorite]
We will be calling back the electrician and plumber (I assume it is the plumber) to install a new socket and check the gas line grounding.
Yikes...
posted by GrumpyMonkey at 5:34 PM on March 6, 2012 [1 favorite]
In the US your local gas company will probably send someone out for free to check and fix any problems on the gas side...
posted by NoDef at 11:49 AM on March 7, 2012
posted by NoDef at 11:49 AM on March 7, 2012
This thread is closed to new comments.
posted by Johnny Wallflower at 8:18 AM on March 5, 2012 [5 favorites]