I always check everything before I work on it. I carry a non contact testet with me, if I get any response at all from it I go get the meter and do some further checking. Simply opening a disco. does not mean the motor is disconnected, I have seen them break, handle in off position load side hot. Never assume the disco. is wired correctly either, I had one with a blown fuse in it, turned it off, checked with meter it was still hot on line side. Someone had wired line in to the load side, could have gotten nasty.
