"My appretice had a cheap meter. We used it on a service call.
We
: turned the power off at a breaker marked for that unit and
checked it
: with his meter. It showed 0 volts. I started disconnecting a
wire and
: got lit up by 240 volts. "

Which is why even after turning off the breaker, or seeing 0 volts,
I still treat it as possibly alive, until I can try shorting the hot to
ground.