My marina has a very sensitive ground fault detection system. Ever since I got my 400EC last fall I've been fighting ground fault trips (it shuts down the whole dock). At first it was the fridge, and after rebuilding the main circuit board it seems fixed. But I'm getting trips without any regularity or pattern. I thought my salon aircon was tripping it, but then it tripped just by flipping the 120V A/C breakers. Basically I've figured out that anything which draws a large power consumption will trip the ground fault (example is a space heater). Everything I've read says to test systems and see what's causing the ground fault, but in this case it seems that anything on the 120v circuit will trip it. So how do I find this ground fault?