First let me explain the set up.

In the main breaker panel there is a 30 amp gfci that protects an indoor swimming pool sub panel in a separate building from the main house. The sub panel is located in the swimming pool room itself. Gfci worked with no problem for about 4 years.

Recently it tripped and wouldn't reset so I tried to isolate the problem in the pool room. There are 5 20 amp breakers in the sub panel. 1}A sump pump 2}pool pump motor 3}underwater pool lights 4}two ceiling fans, wall receptacles and 4 sconce lights. 5}lights in small room above pool. Turned off everything in pool room and gfci was able to be reset. When turning on underwater pool lights gfci tripped. So reset breaker and only ran pool motor and sump motor, along with ceiling fans and sconce lights. Every thing worked ok so I thought is was a short in the underwater pool light.

After about an hour without the underwater pool lights on and everything else running the gfci tripped again. and would not reset. So I started over in an attempt to isolate each circuit. Attempted to run pool pump by itself and it tripped. Than I attempted to run sump pump by itself and it tripped. The only thing that did not trip the gfci where the lights and fan. Ho {lights and fans on wall switches} Now here is where it gets weird, I turn on the fans first then the wall sconces the gfci does trip. However if I turn on the lights, then the fans, then sconces the gfci does not trip. Somehow the order you turn these on makes a difference.

I figured it is was a bad 30 amp gfci in the main panel. I swapped out with a new one and it tripped. So it wasn't the gfci. Next I took out all of the breakers in the sub panel took a little sand paper scraped the wire tips and screws in the panels them selves to make sure contacts were good. Put one breaker in at a time checked when load put on breaker gfci continued to trip in main panel. So I have to have a leak to ground.

Both motors I plugged in (pool pump and sump pump) on separate circuits isolated continued to trip main panel gfci. So I thought maybe both motors were leaking current coincidentally. I got a heavy long power cord and ran it through the hose and plugged in the pool pump motor into a receptacle in the main house in a bathroom that was connected to another 20 amp gfci breaker in the main panel of the house. Pump ran for about an hour no problem no trip. Tried the same thing with the sump pump no trip. I figured it had to be the sub panel itself or maybe wire from sub panel to main panel, or the main panel itself.

Any suggestions would be appreciated. Is there anyway to test an electrical panel for leaks, or the romex running from the main panel to the sub panel without pulling the wire?

 

Welcome to the forums. It helps if you use paragraphs. Without them sometimes it takes a lot of effort to read and understand. Though I haven't read you post I can suggest you disconnect the wires from the GFCI breaker and see if it will reset. If not it is bad. If it will then you need to disconnect all loads on the circuit and add them back one at a time.

 

Is the the feed to the sub underground ?
Geo

 

replace the 5 breakers in the sub panel with GFCI breakers

replace the 2pole 30 amp GFCI breaker with a regular breaker

 

Hopefully not underground.

Your are going to need a fairly good VOM to check for leaks in your electrical system.

The logical place to start is to disconnect the white at both ends and setting the meter to a high resistance setting check from that wire to ground. You should measure no continuity.

 

Ideally I would like to do that, however the sub panel is in the pool room itself. My concern is that the circuit going into the sub and the sub panel itself will not be protected. If someone with wet hands were to touch the panel accidentally after getting out of the pool they would have a negative result. I think that was the reasoning for the gfci breaker in the main panel.

 

Feed is not underground. Part of feed is outside in conduit and part no conduit runs through house basement.

 

Is there any way water could collect in that conduit? I have remove countless conductors that have failed when sitting in a pipe filled with water.
Geo

 

This is a code violation for one thing. NM cable cannot be used outside even in conduit. This could possibly be part of your problem and should be replaced with proper wiring anyway.

We know the OP has NM cable in conduit and water in the conduit, this could be an issue.

 

I don't think so, but anything is possible. The conduit is up high, walk out basement. and under cover all the way to the pool building. It enters the building about 7ft off of the ground, and travels down into the top of the sub panel. Thanks, that is something to consider. I will start with you suggestion. It would be the cheapest and easiest thing to check next.

 

It's still a code violation although that may not be the problem. I'd replace it with proper wiring to rule out it being the problem, you have to start somewhere.