Extreme signs of heat on a GFCI

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copper123

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I had a friend call me last night wondering about a GFCI that was installed at his place last year.
It?s 20 amp rated and only powered from the line side. No loading involved. In the last month a motor home has been plugged into it. I would imagine they used a 30 to 20 amp conversion plug. Anyway, in the last couple of days he said the GFCI had started tripping, and after three times of this, it would not reset. At this point he took out the device. He said that the grounded conductor side of the device was completely melted out. Obviously extreme heat was a work. I asked him if he thought the neutral wire was loose on the device and he was not sure. I also asked him if he checked the branch ckt wires directly back at the panel and he had. I guess it?s a strait shot, dedicated home run back into the panel from the device location. All branch ckt connections were tight. He also metered the branch ckt at the device opening and got a good potential reading between the hot and neutral.
I have been thinking about it today and have been wondering what else could cause the overheating shown on the device besides a loose connection. Could something downstream, IE the motor home bring back an overloaded condition back to the device? If the motor home was pulling high current, ( I am sure it has been) could this cause the device to melt out. Maybe the OC protection is faulty? Just thought I would ask and see what you guys thought.

[ September 30, 2005, 12:31 PM: Message edited by: copper123 ]
 
Re: Extreme signs of heat on a GFCI

You said it exhibited signs of high temperature on the grounded circuit side. If this is a GFCI installed in a panelboard I would guess you are referring to the pigtail that connects to the neutral bus. There should be no current flow at all through that wire. If there is, you have some kind of failure or the device or fault in the wiring.

If it is an outlet type device, then I would guess you are refering to the pass through neutral. The same amount of current should be flowing through it as through the hot side.

[ September 30, 2005, 12:55 PM: Message edited by: petersonra ]
 
Re: Extreme signs of heat on a GFCI

I would guess the load was just too high and the grounded conductor (aka neutral) side of the receptacle was not as durable as the ungrounded side (aka hot).

They just don't make stuff like they used to.
 
Re: Extreme signs of heat on a GFCI

Thanks guys,
Yes Peter, it is a device type GFCI. I have concluded the same thing. It's a 120 volt ckt and the undgrounded and grounded hot conductors should see the same amount of current through them. My only thought was that the current was high but not enough to trip the breaker. The grounded side of the device just couldn't take the high current. You would think that they are UL listed for 100% loading, but maybe not.
 
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