I always use the "screw driver test" when I _think_ the power is off,
just as a last test I short out some of the wires to ground with a
screw driver. If no sparks fly then it all is OK. I do have a couple
screwdrivers with burn marks on them.
I think another good rule is that if you are fixing stuff that is
broken you can't predict how it will work, because, well, it's broken.
so who knows you might just find 220 VAC on a green ground wire.
Broken stuff just doesn't always work like you think. If it did you
would not be fixing it. Yes I have seen hot grounds, the ground was
broken (open) So just jam a screw driver onto everything
Redondo Beach, California