Re: I know it's ungrounded

The problem is usually not the power coming on but a ground leak, somewhere you have to ave ground and if it is through the armor. What usually happens is that any appliance in the house or even in the neighborhood sends leak back through the -phase and that can be enough to kill any sensitive device.

I used to have the sma problem a few years back and when I measured the ground against the cold water, I had somewhere between 75 and 100 V on it (no amps, though, but what happens is that these leaks build up until they discharge and crash your box).

Easiest thing to do is to run a 30Amp ground wire to the nearest cold water line, this is even within code in most states.