Lights Tripping GFCI Problem

[JohnT]

It sounds like you have a short somewhere in either the lights or the Jandy dimmers.

A short won't trip a GFCI breaker unless it is a hot to ground short (also known as a ground fault). A "normal" hot-neutral short will trip the circuit breaker. GFCI's trip when the current in the neutral is different from the current in the hot line. That's something that usually doesn't change during operation unless there is movement that causes a ground fault. 99 times out of a hundred a situation like this is a bad GFCI.

A possibility is a damaged neutral wire or loose connection that is heating up and conducting poorly. Worth a look.

[craiga]

i did a little more testing and found that the problem only occurs in the pool light circuit and not in the spa light curcuit (there are seperate relays for each). Also, the pool light curcuit only trips the GFCI when the lights are on at 100%. Anything dimmer (75% and lower) does not trip. Any thoughts?

[JohnT]

Are the relays the same so you could try swapping them? I'd guess you're on the right track, but swapping them could prove it.

[craiga]

John:
Yes they are the same. Good idea; I'll swap them and see what happens. Thanks for your reply.

[craiga]

Swapped them and no change. I guess that rules out the dimmer relay. Shouldn't there be a junction box somewhere between the light and the panel? I have never seen/noticed one.

[JohnT]

Swapped them and no change. I guess that rules out the dimmer relay. Shouldn't there be a junction box somewhere between the light and the panel? I have never seen/noticed one.

There's often a box behind the light above the ground about 12". Interesting (and I'm sure aggravating) problem. Does anything else share this circuit, particularly after the GFCI?

[craiga]

John; i couldn't find a junction box and finally called the builder and was told there is not one. Nothing else on that circuit except the pool lights, which are two (500 watt) lights. I threw in the towel and placed a service call to the builder's electrician to come look at it. i'll let you know the results.