12V LED light tripping GFCI - eventually

[drogers]

Hey all,
I recently replaced the 120V lights in my spa and pool with 12V LEDs. We never used the 120V ones in 4 years, as they were very old and we didn't trust them at all...

The pool light has a j-box about 15 feet from the light niche, so that's where I installed the transformer/control box. After being on for between 5 and 20 minutes, the GFI breaker would trip (only for the pool, not the spa), so I replaced both the light and transformer, and re-did all of the wiring in the j-box (new wire nuts etc). Still tripped. So I replaced the GFI breaker with a known working GFI outlet (the one the spa was wired with) - that trips too.

Soooo, now I'm left with the wire between the panel and the j-box. Is there anything else I can check before I have to pull 75' of new 12ga?

 

[Rocket J Squirrel]

Is there any chance water, or even moisture, is getting into the j-box, via irrigation runoff, leakage from the light conduit, or any other way? I had that problem and it was not easy to solve. But I did solve it eventually.

 

[drogers]

Is there any chance water, or even moisture, is getting into the j-box, via irrigation runoff, leakage from the light conduit, or any other way? I had that problem and it was not easy to solve. But I did solve it eventually.

The box is about 3’ above pool level, 12” above the dirt in a built in planter box, so it’s clear. Also, it trips with the box open and wires exposed in 100* dry heat….

I supposed there could be (heck, probably is) water in the underground PVC, but that shouldn’t affect properly run THHN. Which possibly brings me back to needing to run new THHN so I know it’s THHN and properly done.

Ugh.

 

[ajw22]

I supposed there could be (heck, probably is) water in the underground PVC, but that shouldn’t affect properly run THHN. Which possibly brings me back to needing to run new THHN so I know it’s THHN and properly done.

You should be using THWN or THHN/THWN wire.

 

[drogers]

You should be using THWN or THHN/THWN wire.

Good point, considering that I don’t know the conduit is intact or dry. THHN *should* be ok but it’s not worth the cost savings if I have to do it again in a few years.