I have a two-year-old in-ground 10K-gallon Gunite pool with all Pentair controls and pumps. The electrical installation was done by an electrician who primarily does pool installations. The pool passed multiple electrical inspections by the city inspector. The filter pump is a 3-hp variable speed Pentair Intelliflo model. The pump is on a dedicated 20-amp GFCI breaker installed in an EasyTouch 8 outdoor control panel. The pump is approximately 6 feet from the breaker. The pool filters are clean and the baskets are free of debris. The pool water is fine.
About a year ago, the GFCI breaker began to sporadically trip (weeks without a trip, then perhaps once or twice in one week). There was no noise from the pump when it started or while it was running. The breaker reset without a problem. Because the system was still under warranty, I contacted the contractor who immediately sent out the electrician. I was not at home, but the evidence suggests that he replaced the GFCI breaker. This seemed to fix the problem, or so I thought. A few months later, however, the same problem reappeared---very sporadic tripping of the breaker. It seems unlikely the new GFCI is bad. This is what I have tried to fix the problem:
1. Swapped out the filter pump relay. Curiously, the tripping stopped for a while after I did this, but it returned again later.
2. Ensured that all the electrical connections in the control panel and at the pump are tight.
3. Looked for water infiltration from rain at the panel and between the panel and the pump. I noticed that the wires for the pump passed through a junction box. When I looked inside the junction box, there had obviously been rain water infiltrating the box, but the wires themselves were dry. I sealed the junction box with silicon caulk and thought that this should solve the problem. It did not.
At this point, I am thinking it could be one of these issues:
1. There might be a nick in the wires running from the breaker to the pump. Although the wires are in above-ground outdoor-rated conduit, we live in a hot, humid climate. Perhaps the moisture builds up in the conduit, causing the fault.
2. The pump periodically pulls too many amps, tripping the breaker (i.e., the pump is bad). I could measure the amps with a clamp-on ammeter, but unless I catch it when it trips, it will not be high.
Before I replace the wiring and/or replace the very expensive pump, does anyone have another suggestion for what might be causing the breaker to trip? Should I try a different brand GFCI breaker?