[see
Forum Thread this is taken from for more]
Inverter grounding with Grid/Shorepower
The purpose of the ground is to provide a path for the hot-wire to short to so it can trip the fuse (rather than short through you).
So the ground should go back to the source of power generation that has the fuse/breaker.
When the inverter is using the grid, the ground should be to the grid's ground. When you're in inverter mode you want the ground to go to the inverter's ground so the inverter can trip the circuit. In a vehicle, the inverter's ground typically goes to the vehicle frame, so if the AC hot wire touches the frame it'll trip the circuit.
