electrical grounding

Earlier this year PG&E installed a free backup power transfer meter at our California property (info sheet here). Using the L14-30P cable they supplied, it connects our Honda eu7000is inverter generator (manual) to power the whole house. Overall it works well. We have noticed some odd behavior...

I was looking at a 3" ABS drain for a toilet in the basement, standing on the plastic toilet seat, accidently touched the 1" copper pipe and WOW!! I got shocked. The copper pipe right here. And then I went outside to check the grounding on the panel, just one rod in the ground, and nudging...