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Author Topic: Electrical Fire in Stove  (Read 2363 times)

Mike Sokol

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Electrical Fire in Stove
« on: November 09, 2016, 06:20:24 pm »

My dad's rental property nearly burned down this morning. His tenant had installed a used electric stove about 8 years ago, and this morning there was a fire in the wiring right next to the flammable wall in the 100 year old house. From what I can see, it appears that they never installed a strain relief or grommet where the 50-amp plug wire enters the junction box on the rear of the stove. I'm sure that 8 years of vibration and heating sawed through the insulation enough to make contact, but not a solid enough short to blow the 40-amp cartridge fuses in the fuse box. Luckily the tenant was home at the time and used a fire extinguisher to extinguish the flame. Plus they said there were a lot of sparks in the back of the stove. Close call...
« Last Edit: November 09, 2016, 06:28:31 pm by Mike Sokol »
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Tim McCulloch

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Re: Electrical Fire in Stove
« Reply #1 on: November 09, 2016, 08:56:59 pm »

I cook with gas.  I hope I'd smell the equivalent leak.  Yikes, Mike!
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John Roberts {JR}

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Re: Electrical Fire in Stove
« Reply #2 on: November 10, 2016, 09:11:51 am »

Glad nobody was hurt.

JR
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Jonathan Johnson

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Re: Electrical Fire in Stove
« Reply #3 on: November 10, 2016, 11:02:57 am »

From what I can see, it appears that they never installed a strain relief or grommet where the 50-amp plug wire enters the junction box on the rear of the stove.

From what I've seen, ranges don't come with cords, or strain reliefs. The strain relief (cable clamp) comes with the cord. And the strain relief they supply with the cord is a cheap piece of junk that's very difficult to install, so many people just say "phooey" and don't install it. I've even seen where the supplied strain relief pulls out of the terminal box, even when installed "properly" according to instructions.

Since this was a used range, who knows. It's probable that it came with the cord already (mis)installed. Or maybe someone needed to replace the cord, and grabbed a used cord that didn't have a strain relief with it any more.

A 3/4" "Romex" clamp works a thousand times better.
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Mike Sokol

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Re: Electrical Fire in Stove
« Reply #4 on: November 10, 2016, 12:11:12 pm »

A 3/4" "Romex" clamp works a thousand times better.

Agreed. I've offered to oversee the installation of their "new" stove, whatever that turns out to be. And I'll even buy them a new power cord and Romex clamp just so I don't worry about this happening again.
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lindsay Dean

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Re: Electrical Fire in Stove
« Reply #5 on: November 10, 2016, 03:07:37 pm »

I've seen cords on stoves melt the shield because the "installer" never tightened the nuts on the conductor correctly and as the range is used over time the contraction and expansion  makes more and more space to arc and finally over heats the wires insulator and presto you got you a batch of wires burning , good thing  the "installer" put the cover back on or it could have spread fast.
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Chris Hindle

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Re: Electrical Fire in Stove
« Reply #6 on: November 10, 2016, 03:16:52 pm »

From what I've seen, ranges don't come with cords, or strain reliefs. The strain relief (cable clamp) comes with the cord. And the strain relief they supply with the cord is a cheap piece of junk that's very difficult to install, so many people just say "phooey" and don't install it. I've even seen where the supplied strain relief pulls out of the terminal box, even when installed "properly" according to instructions.

First Range I installed at the house, I had to supply the cordset. 15 years ago, Kenmore brand. Had to run to the hardware so I could cook supper.
Put in a new Whirlpool 2 weeks ago, and it had the cordset, and a decent strain relief supplied. I took the cordset I bought back to Home Depot.
Don't know if it was Whirlpool or the store, but I suspect Whirlpool did it.
Bought a washer/dryer 6 or 7 years ago, Whirlpool, and again, the 240 was already installed on the dryer.
The instructions with the Dryer talked about installing a cordset. The Stove didn't.
Chris.
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Jonathan Johnson

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Re: Electrical Fire in Stove
« Reply #7 on: November 10, 2016, 04:16:51 pm »

Agreed. I've offered to oversee the installation of their "new" stove, whatever that turns out to be. And I'll even buy them a new power cord and Romex clamp just so I don't worry about this happening again.

The cord in the picture appears to be the type with a NEMA 10-50P (or worse, a 10-30P) plug on the end, without separate ground. You might double-check to see if you can safely upgrade the receptacle to a NEMA 14-50R, and ensure that the new range has a NEMA 14-50P cordset. Be sure that the jumper is removed from between neutral and ground terminals in the range's connector block.

I know how you feel about bootleg grounds.  ;)
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Mike Sokol

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Re: Electrical Fire in Stove
« Reply #8 on: November 10, 2016, 04:24:26 pm »

The cord in the picture appears to be the type with a NEMA 10-50P (or worse, a 10-30P) plug on the end, without separate ground. You might double-check to see if you can safely upgrade the receptacle to a NEMA 14-50R, and ensure that the new range has a NEMA 14-50P cordset. Be sure that the jumper is removed from between neutral and ground terminals in the range's connector block.

I know how you feel about bootleg grounds.  ;)

Well, here's a picture of the service panel, which is original to the house. Ugh... I checked and there are 40-amp cartridge fuses in the stove side, and that's a 30-amp 10-30P receptacle. So chances of getting an upgrade are slim without a major rewiring project. Best I can do is change out the cartridge fuses for 30-amp, and make sure the new stove wiring is correct.
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Jonathan Johnson

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Re: Electrical Fire in Stove
« Reply #9 on: November 10, 2016, 04:54:48 pm »

Well, here's a picture of the service panel, which is original to the house. Ugh... I checked and there are 40-amp cartridge fuses in the stove side, and that's a 30-amp 10-30P receptacle. So chances of getting an upgrade are slim without a major rewiring project. Best I can do is change out the cartridge fuses for 30-amp, and make sure the new stove wiring is correct.

Double check the wiring from the fuse panel to the range receptacle. If it's of sufficient gauge to support 50A, upgrade to a 10-50R receptacle and a 10-50P cordset. Be sure to hook up that bootleg ground!  ;)

On the other hand, the fact that arcing was present for an extended period of time, enough to cause a fire, seems to indicate that the current flow was not sufficient to blow the 40A fuse. If the wiring is too small, i.e., 12AWG, then maybe the wiring itself was limiting the current. Or maybe the arcing just didn't pass enough current.

Looks like a typical, extremely common 60A fuse panel. There must've been tens of millions of those made; they seem to be in every old house and outbuilding in America. And to think that many homes now have 400A service!
« Last Edit: November 10, 2016, 05:00:56 pm by Jonathan Johnson »
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Re: Electrical Fire in Stove
« Reply #9 on: November 10, 2016, 04:54:48 pm »


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