Agreed with most of what was said. But here’s another potential issue even if you fix the ground faults. An intermittent (arcing) ground fault on an ungrounded system acts like a charge pump. It jacks up the fault voltage until it finds the weakest insulation anywhere in the system. I mean anywhere. This is the only thing that keeps the voltage from going infinitely high. Typically something burns up at 6 to 8 times system voltage so around 1500-2000 V in your case. I suspect this might be what is burning up everything even without double ground faults. This is typically what happens. Once you fix this, expect electrical issues to drop to about 25% of what you are experiencing now.