After installing a second outdoor fan, I tied into an existing fan under an enclosed porch.I decided it would be smart to install a gfci breaker to protect them (vs the standard breaker).
The circuit is tied into my kitchen an outdoor spot lights. With all the individual light circuits either isolated with the wall switch or disconnected, the gfci continues to pop.The only thing I can think of is the power source to the lighting switch box is faulty.Am I on the right track? How can I troubleshoot the switch box incoming power.Thanks for any help you can provide.

Check to be sure this is a 2 wire circuit, if it is a 3 wire, with two hots(circuits) and a common neutral,this will cause a GFI to trip. Reverse polarity may be the problem also.

You may think you have everything isolated,but there most likely is a tap feeding something else live power.

The paddle fan(s), do either of them have a light kit, that you can only operate using the pullstring on the fan? This is an example of unswitched power in the circuit.

You mention kithcen light... are any of the light fluorescent? The ballasts commonly have a small amount of current flowing to ground, thus, a ground fault.

The possibilities are endless. The GFI is clearly doing its job, but either may be due to a real ground fault somewhere in the circuit, or the circuit is miswired. Very difficult to troubleshoot a problem like this here, all I can do is give you an idea what to look for.

You may need to begin taking all the wires apart ateach device, light, switch, and energize the circuit a little at a time to finally find what is causing the GFI to trip.

Not sure how much of this helps. Check all the causes I have mentioned and see if you can locate the culprit. If you need more help get back with your questions, and any more detail you can offer.

This is a 2 conductor circuit. I will look to see if any other circuits could be tapped off as you suggested. Thanks, will give you an update.

There are two lighting circuits that utilize 3 way switching. Is this what you are referring to as a 3 wire circuit? Thanks.

I think what TK meant was a circuit like an electric range that is 240v with the light, timer, and the heating elements part of the time feeding back the neutral. The common 3 way switches shouldn't be a problem. Check all the neutrals too. If one of them is shorted to ground, it could trip it too. Otherwise, disconnect everything, and connect it back one wire at a time as he said.

Two lighting circuits? Do they both use one neutral, using a 3 wire cable, black red, and white, from the panel out to the lighting fixtures.

If this is the case, then this is the problem, GFI breaker cannot protect one circuit that shares a neutral.

And Labman mention something I did mean to mention before, anywhere in the circuit, the neutral may be shorted, or connected to the bare or green equipment grond, this will cause the GFI to trip also.


I kind of refer to this asking about polarity.

Good catch Labman

A clarification on the 3 wire cable. Carefully note TK said between the panel and 2 lighting circuits. You can run 2 circuits off a 3 wire cable, which messes up GFI. He was not referring to the 3 wire cable from one switch to the other. Sometimes real experts don't realize how much detail DIY needs.

Thanks all for your help.

Your welcome, but can you get back to us with what you found to be the problem.

Those of us who answer like to see how we have helped, what the problem was, and how you corrected it.

This helps us with providing better answers in the future.

Thanks