electrical
My Christmas lights keep tripping my GFI in the rain.
I've got one of those Light Show boxes with 6 different sections of lights plugged into it. When I have all 6 sections plugged in, the GFI trips immediately. However, if I try them one at a time, the GFI doesn't trip.
If there was a ground fault in any of the sections, wouldn't it always trip the GFI? What am I missing? How do I debug this problem?
Can "high instantaneous current" also trip the GFI?
Some surge protectors work by "redirecting" surges to the equipment ground, which is pretty much the definition of a ground fault. In this case, it's definitely possible that surge suppressors could be tripping GFCI receptacles/breakers (given a large enough surge).
As for the AFCIs... When electrical contacts separate, they often create an arc between the contacts. This arc spans the gap until the contacts are too far apart, and the arc can no longer be sustained. It's possible (in theory) that the GFCI tripping could create a large enough arc, for long enough to cause the AFCI to trip. It's not likely that a properly functioning GFCI would do this, but if the GFCI was old and worn it could be opening the contacts slow enough that a detectable arc is being produced.
Determining if the GFCI tripping is causing the AFCI to trip, is a simple test. Simply press the test button on the GFCI. If the AFCI trips, you'll have figured out half the problem. If the ACFI does not trip, you could repeat the test using a receptacle tester with a GFCI test function.
If it's determined that the GFCI is causing the AFCI breaker to trip, replacing the GFCI receptacle may resolve that part of the issue.
Figuring out if the surge suppressor is tripping the GFCI, is a more difficult proposition. It will likely require you to monitor the supply voltage over some time, to identify and document possible surges.
For everyone's info, and because it could help someone else, here is the actual answer in my case.
While I had connected the white wire coming out of the AFCI to the ground bar, I hadn't connected the neutral from the circuit to the AFCI. In my case it was because I didn't realize the extra screw terminal was actually there and the documentation wasn't helpful.
Bottom line: If you install a combination AFCI and connect the hot but not the neutral, it will not pop until there is a load. After the fact, that actually makes sense. This is like a ground fault from the AFCI's point of view because it can't see the current going back through its neutral port.
Best Answer
GFIs don't actually measure "ground fault", they measure the difference between the current (amperage) going in and the current going out. It sounds like the current is leaking a little bit on each one, but maybe in not sufficient magnitude to trip the GFI. Try doing 2 or 3 and seeing what happens..