tripping

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resistance

resistance

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WA
I was told I would need to go check a GFCI that trips anytime a customer installs a light bulb into a fixture. The circuit holds fine until a load is added--once a load is added, the GFCI trips. I haven't had a chance to make it over to the house, but thought I would get your input! Just another note: The GFCI holds fine while the switch is on without a load! This will save me some time when I get there. I have a few ideas, but your input is appreciated. I'm kind of burnt out!! Thanks!

Just want to get your input.
 
Re: tripping

You have a neutral to ground short in a box downstream of the GFCI. A gfci trips on a grounded neutral, same as an AFCI (but its a 30 ma trip). It will only trip with a load, as it sees it as a ground fault-needs 4 to 6 mA. It will be in the last box you check.
 
Re: tripping

It will be in the last box you check.
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Tom, is that humor? Because you left out the part about that box being the hardest one to get to. In the attic, at the other end of the building, on the other side of the glu-lam, that's 10 inches from the roof, that was built with 11" long nails, and there's a gaping hole in the HVAC ducting, and a "cold" person who replaced the heater thermostat with an on switch lives there. :D
 
Re: tripping

The one in the attic over the glu-lam?

It'll only be there if you check it last. :D
 
Re: tripping

Originally posted by tom baker:
It will only trip with a load, as it sees it as a ground fault-needs 4 to 6 mA.
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My Cooper GFI's trip under no load with a neutral to ground fault...?

My guess is a bad GFI. Or, on the outside, a ground fault in the fixture. :)

I concur with the above, it will be in the last box you check, unless customer is attractive.
 
Re: tripping

George,

No current from neutral to ground. But, neutral fault to ground. After line is applied across the load then current splits up to follow both neutral and ground paths back to sourse.

Edit: and that's true too George, you could easily have a neutral fault with current on it.

[ February 02, 2005, 08:04 AM: Message edited by: physis ]
 
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