main breaker will be OFF ....
I am not an electrician. But I have a friend who is and he said I must TOTALLY ISOLATE the back-fed system from the grid. He said if I had no complete 3 pole switch, I should remove the meter.
I do not remember the reason but it was something about the main breaker only opening up one of the three lines. Perhaps someone with a real understanding of power lines could refresh/dispute my friends comments. It might have been something specific to my wiring, but I got the impression that it was standard practice to break all wires to the grid, including the ground.
Nomad.