Lights Tripping GFCI Problem

[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.

[craiga]

Well, pool repair guy came out and said there is a small amount of water inside the light assembly. Dosen't know if the gasket is leaking or the assembly is cracked. Reccomends replacing entire assemly instead of just the bulb (which would come with a new gasket). Said the reason it only tripped on 100% was because any other setting did not draw enough amps to trip the gfci. Just thought this info might be helpful to someone else with a similar problem.

[JohnT]

Said the reason it only tripped on 100% was because any other setting did not draw enough amps to trip the gfci. Just thought this info might be helpful to someone else with a similar problem.

That scares me a little, because the GFCI trips at just a few milliamps, and does so almost instantaneously. I can't come up with an explanation for the time delay, particularly the fact that it took the same time to trip when the breaker was reset. The water is there, the bulb is hot and the dimmer is at whatever temperature it is going to stabilize at. I could see it tripping after 5 minutes the first time, and then much more quickly upon resetting.

Glad it's fixed, but still a puzzler. I would have assumed (incorrectly apparently) that water would have given an instant trip.

[craiga]

Well, I'm with you. Kind of blows the way i thought a gfci would work. I would have thought that once water penetrated the assembly, it would trip the gfci instantly upon any current being transmitted. Its not like the water ever drains out and the thing dries out before the next test. Its not fixed yet though, repair guy has yet to replace the light assembly and test his diagnosis.

[CarlD]

Have you replaced the GFCI, to ensure it's not failing?

The only other thing I can think of is there aren't enought minerals in the water to allow it to pass much of a current, so there isn't enough to trip the GFCI until the level is 100%. Or you are getting a capacitor action that discharges and trips it.

But a GFCI should trip at the slightest imbalance in the poles...but it's 12v right?.......

[craiga]

Carl,
Sorry for the delay in this reply, i've been unable lately to check the forum. Yes, i replaced the GFCI and eliminated it as the problem. Pool Guy also did the same thing and found no problem with it. The system is 120v. Its still not fixed yet, but the pool guy is going to replace the light assembly and bulb.