Ground Fault Issues

[Jmreim]

Our marina installed new docks this year and along with them came new electrical wiring that meets the regs on ground fault breakers. Once we plugged into this new dock, we discovered a ground fault issue. After some detective work, we replaced our water heater and the problem disappeared - that was 3 months ago and we've had no issues.

Unfortunately, our ground fault problem reappeared this weekend after we replaced our air conditioner. We had taken the boat to a different location (no ground fault breakers), did the work and the new air cond. worked perfectly. We then brought it back to our regular dock, plugged in, turned on the air cond. and the ground fault breaker tripped immediately. The ONLY thing that changed was the new air cond. Every other 110V circuit on the boat appears to work normally and does not cause a ground fault - the ground fault breaker trips only when the new air cond. is switched on.

I'm puzzled by this - the new air cond. is wired exactly the same - why would it now cause a ground fault? Do we have a larger issue someplace? Might an isolation transformer be an effective shortcut to solving this or is that not the right approach?

Thx -
Jim

 

[rslifkin]

Something is wrong in that new A/C unit or the wiring for it. Either something is leaking to ground or there's a short between neutral and ground in the unit. Either will cause a GFI to trip.

 

[tiltrider1]

First I would disconnect all the wires to the AC to verify that it’s the problem. It in fact might not be the issue but a coincidence of timing. Had that issue give us heart burn one day when we replaced a fridge.

Yes an isolation transformer is the quick way to deal with this. Not the cheap way in the short run but possibly in the long run.