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Electronics => Beginners => Topic started by: Circuitous on July 02, 2013, 02:01:56 pm

Title: Help tracing GFCI fault
Post by: Circuitous on July 02, 2013, 02:01:56 pm
One of the GFCI circuits in my house keeps tripping.  It's installed in a bathroom outlet, but it also supplies a couple of outdoor outlets downstream.
I replaced the GFCI unit over the weekend, but when the house painters arrived today it tripped again.
I had them use a different outlet in the garage, and that seems to work fine.  I don't think its their equipment, as they weren't working over the weekend when we experienced the earlier problem.

Is there a recommended way to identify/test the outlets and the wiring in between them?
I'm not at home at the moment, but I expect that there's been a build up of corrosion, etc in one or both of the outdoor sockets.

Some tools I have available include:  Fluke 289 and an insulation tester(250 - 1KV)


Title: Re: Help tracing GFCI fault
Post by: Monkeh on July 02, 2013, 02:16:21 pm
Insulation resistance (without the RCD in the circuit) between both live conductors and earth should show you the problem.

It's probably condensation or a spider or something in the outdoor socket, usually is..
Title: Re: Help tracing GFCI fault
Post by: cthree on July 03, 2013, 05:29:00 am
Are you sure that you don't have more than one GFCI in the same circuit? That will cause one to repeatedly trip. I'd check that first.
Title: Re: Help tracing GFCI fault
Post by: Circuitous on July 03, 2013, 12:20:11 pm
I have identified all 4 outlets on the circuit, the GFCI and 3 regular outlets downstream.  I recall reading that you can only have one GFCI in line, I suppose that the downstream GFCI might appear as a leak to ground to the upstream one?

I replaced the outdoor outlets, and everything is working fine (tested it under load).  When replacing a sheet of siding last week, the carpenters removed and reinstalled one of the outlets.  They had wrapped some of the wiring in electrical tape.  Not sure if that trapped some moisture or what.

Thanks for all of the suggestions. 
Title: Re: Help tracing GFCI fault
Post by: Monkeh on July 03, 2013, 02:49:00 pm
Are you sure that you don't have more than one GFCI in the same circuit? That will cause one to repeatedly trip. I'd check that first.

And how would it do that?

I have identified all 4 outlets on the circuit, the GFCI and 3 regular outlets downstream.  I recall reading that you can only have one GFCI in line, I suppose that the downstream GFCI might appear as a leak to ground to the upstream one?

No, you just don't know which one will trip (and it's very possible they'll all trip, which is just plain awkward).
Title: Re: Help tracing GFCI fault
Post by: richcj10 on July 03, 2013, 03:00:27 pm
First, make sure your line/load is connected correctly.
With a GFCI protecting out side outlets, I would assume your issue is out there.
Something could of made home on one of the outside outlets.
Title: Re: Help tracing GFCI fault
Post by: MacAttak on July 03, 2013, 10:39:12 pm
When replacing a sheet of siding last week, the carpenters removed and reinstalled one of the outlets.  They had wrapped some of the wiring in electrical tape.

And that's why it's a good idea to never let someone modify electrical wiring unless they are qualified to do it.

Even when a licensed electrician is performing work, I still watch everything they do. I don't care if they like it or not... I'm the one who ends up with a house fire if they aren't competent.
Title: Re: Help tracing GFCI fault
Post by: duskglow on July 03, 2013, 10:56:15 pm
And that's why it's a good idea to never let someone modify electrical wiring unless they are qualified to do it.

Even when a licensed electrician is performing work, I still watch everything they do. I don't care if they like it or not... I'm the one who ends up with a house fire if they aren't competent.

And in there is probably the answer to your question.  Hire an electrician.