Lights Tripping GFCI Problem

[craiga]

My lights, when turned on, are tripping the GFCI after they have been on for about 5 minutes. I have Jandy dimmer relays installed between the GFCI and the light circuit. Has anyone else had this problem? I changed the GFCI and it still does it. It seems odd to me that there would be a delay, because if there were a ground fault, it would be instant. Anybody got any ideas?

[JohnT]

My lights, when turned on, are tripping the GFCI after they have been on for about 5 minutes. I have Jandy dimmer relays installed between the GFCI and the light circuit. Has anyone else had this problem? I changed the GFCI and it still does it. It seems odd to me that there would be a delay, because if there were a ground fault, it would be instant. Anybody got any ideas?

You are thinking like I would. Changing the GFCI would have been my first and second guess. The delay seems really odd. Once it trips, what happens when you reset it? Another 5 minute delay? Sure doesn't sound like a ground fault if so.

Is it an outlet or a breaker type GFCI?

Anything else on the line that could be causing an unusual load?

[CarlD]

I think you are looking in the wrong place. GFCI doesn't pop under load--that's the breaker's job. GFCI detects an imbalance between the poles and shuts down. I think the GFCI is doing EXACTLY the job it's supposed to do--shut down when there's a ground fault.

It sounds like you have a short somewhere in either the lights or the Jandy dimmers. I would start testing there. It also sounds like it's an intermittent short, too. I would STRONGLY recommend you not use the pool until the problem is solved or the lights are completely disconnected from all electricity, either by unplugging or if hardwired, removing the wiring.

Why do people always assume that when a breaker or GFCI keeps popping its a bad breaker or GFCI, not that they are doing their job of protecting you?

[craiga]

John, it is an outlet type GFCI, and after reset another 5 minute delay occurs. Nothing else on the line except the lights. I did find out however that there was thunderstorm/lightning occuring just prior the this problem surfacing (I was out of town). Maybe these dimmers are fried, but still the delay sounds like something is heating up and then causing the problem. Carl, I know i have a problem and don't doubt that the GFCI is doing its job. I changed it because i wanted to eliminate the possibility of it being bad. I have had a couple of them go bad before, so i know it is possible. It is quick, easy and cheap to replace one, and if that is not the problem and you find yourself with a spare, no big deal.
Thank you both for your replies.

[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.