GFCI Receptacle Gone Bad

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  #1  
Old 12-30-20, 01:22 PM
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GFCI Receptacle Gone Bad

So this isn't your standard GFCI worn out needs to be replaced situation. I've got a GFCI circuit to my kitchen. 20A breaker and I verified that the line an load are both 12/2 wires. Wiring is romex and I suspect it was done in the 1990s when the previous owners likely did a kitchen remodel.

I've twice now had the wires melt at the GFCI. I think both times were on the load side but not certain about the last one (forgot to take a picture and it was about 9 months ago) and the wire clearly burned (i believe it was the neutral load wire). Just had it happen again and it appears to have melted a little bit on the load side but I can't be certain. There is no burn marks but the outer most part of the hot load wire looks a little melted. We certainly smelled a little smoke and the gfci did trip.

There was little load on the breaker at the time. The only thing on it were two small ac/dc convertors and a Christmas light timer. I was also able to figure out that the load side then appears to on to power some outside outlets somewhere further down the line. (breaker on but load wires disconnected verified that). The outside outlets have a GFCI of their own though (so there is a GFCI on an already GFCI protected line) and that GFCI did not trip. That is where the Christmas light timer is.

I disconnect the load wires and rang them with my DMM to make sure there wasn't a short somewhere down the line and it the two wires both came back as isolated from each other (i.e. infinite resistance). I was also able to reset the gfci and with nothing plugged in (load side still disconnected) it didn't trip off. I suspect that if I connect the load side again, it still won't trip.

Any ideas on what may be going on here or how I should further trouble shoot this?
 
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Old 12-30-20, 01:36 PM
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Loose connection that is overheating. Even if it was too much load, a tight connection will not overheat. The breaker will trip.
Is this copper wire?
 
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Old 12-30-20, 01:46 PM
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Loose connection that is overheating. Even if it was too much load, a tight connection will not overheat. The breaker will trip.
Is this copper wire?
That's what I thought too, but where would the loose connection be? I made sure the connection wasn't loose at the GFCI. everything was screwed down tight, and this was the second time it failed. seems odd that the pervious install before we had the house would go bad and then the one I did as well. Not saying that isn't the problem. Just seems really odd to me especially since it's been 9 months since the install and there was no real load to speak of at the moment. I don't suppose I can just blame 2020 right?

And yep, copper wire.
 
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Old 12-30-20, 02:14 PM
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but where would the loose connection be?
Where the heat is being generated.

Did the connections to this outlet use the backstab slots or the screw terminals?
 
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Old 12-30-20, 02:40 PM
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I guess I could pull the other plates and see if there is any Burning on any of the other receptacles and that maybe Iím smelling the burn from someplace else.

They werenít backstab, but one of the terminals was back screwed (or whatever that is called. Then others were screwed down to the side terminals.
 
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Old 12-30-20, 07:15 PM
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Just checked the other outlets and none seem to have loose connections as near as I can tell and no smell of burnt wire. I didnít pull all of them out though to be fair.

i powered just the gfci and it seemed to work just fine. Hooked the pods back up and the gfci trips immediately on power being added to the circuit. Cant reset it either. Guessing the GFCI is fried at a minimum but still doesnít explain the original trip.

im at a loss.
 
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Old 12-31-20, 10:52 PM
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When you see melted or charred wires/device, that's where the heat is occurring. So it had to be a loose connection, at the GFI. If it's a smaller box, and the wires and device is crammed into the box, it could be pulling the wires out enough to cause a loose connection (though unlikely).

Also, in a kitchen done in 1990, I believe the code required 2 dedicated kitchen circuits back then too, but regardless, it really shouldn't be that much of an issue.

A new GFI with properly torqued connections should never have another problem.

Oh, and just to confirm, the panel is a reasonably modern breaker panel, right? The kitchen circuits protected by a 20A breaker?
 
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Old 12-31-20, 11:14 PM
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Yeah the box is a little tight and with the 12
awg it can be tough. The new gfci I got is a ďslimĒ so hopefully that will help I hope.

There are 2 circuits so thatís good. I have half my outlets still :-)

And yep. Panel is only 2 years old. Had the the remaining knob and tube pulled from the house a couple years ago and put in a new panel then too.
 
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Old 01-09-21, 02:40 PM
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OK so I have made a little progress. Attached here is the diagram of what I've been able to figure out on the circuit. I replaced the GFCI and put everything back away. Things seemed good for a hot minute, then I applied power again and things weren't good. Noticed a lose neutral in box 1. Fixed that. Things seemed good. Then bam, GFCI trip. No smoke or anything. Just a trip.

First check was box 2 on its own. It seemed to work fine. No nuisance trips or anything. Then I check everything downstream of box 7. No trips. Put it all back together and no trip. Then I plugged a very small ac/dc convertor into outlet 3. GFCI #1 tripped. After a breaker recycle I was able to reset the GFCI, but it tripped again.

That's what I got really annoyed. LOL. I disconnected outlet 6 in hopes that it was causing the problems. No dice. Tried the same for outlet 3. No dice. Then I bought a wire tracer and started tracing wires. Found box 7 in the crawl space at that point. Which led me to figure out a few things that I won't go into detail.

Box 5 was replaced by an electrician a couple years. It was an unground outdoor outlet. I believe the electricians used the existing 2 conductors and then just pulled a ground wire. Wish they would have run new romex from box 7 but that would have been much more a pain than just a ground I think. I haven't opened box 5 because it is weather sealed with silicon, so I can't verify if box 6 is on line or load side of gfci 5 but if memory serves I think at one point i was able to determine it was on the line side. I haven't been able to trace where the mystery conductors from box 4 go.

I have now disconnected the 2 conductors running between box 4 and 5. Things seem stable in everything else. I was able to plug a toaster into #3 and gfci didn't trip. So right now it seems like something is wonky downstream of #4. With the wires between 4 and 5 connected, plugging a toaster into 3 causes the gfci to trip and can't be reset without a breaker cycle.

So a couple questions
1) is it possible that the separate ground in box 5 is causing a problem?
2) if I break the weather seal on box 5, can I get reuse the seal with new silicon caulk or do I need to get a new seal?
3) do you all have any other idea of what to check next or what I should replace next? I thought this might be a water intrusion thing, but it's been dry for a couple days and it's not like it wasn't wet before.

Thanks!

 
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Old 01-12-21, 12:54 PM
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Is the wire insulation melted or are you just seeing burn/soot marks at the screw terminal?
Think you have to break the seal to be sure. Check for white wires marked with black tape just in case someone did something weird.
You can re-silicone or you can get a new gasket for very cheap anyway...
 
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Old 01-14-21, 05:49 PM
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If you use the back wire feature and tighten the screws to the pressure plates sufficiently you will not have the overheating problem at connections.
 
 

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