I do not know if the wire was damaged by the roto zip of the dry wall guy or if the wire was pinched when stuffing the MS into the box.
It was the wire on the load side of the switch, the MS was installed and the circuit turned on, then when someone pushed the button on the MS it "lit up".
Remember this is just a 277 volt fault not a 480 fault and the 20 amp breaker never tripped, the wire was blown apart clearing the fault.
Just something to think about before sticking your fingers into a live 277 volt (or any voltage) box.
On the same job a sprinkler contractor thought he would help me out and move a live 277 volt 2' x 4' troffer, well the wiring plate came off when it was jammed against duct work and the 12 AWG was cut into by the troffer.
Again the breaker did not trip, the wire just blew apart, this guy did not even know how lucky he was not to have gotten blasted.
My guess is the wooded ladder kept him from being a conductor, as the light fixture enclosure was 'hot' for a short period of time.
Bob Badger Construction & Maintenance Electrician Massachusetts
#36397 - 04/06/0405:41 PMRe: Something to Remember before working Live
can anyone get me some info. i still don't look through these things, like breaker reset arc-flash ect. never heard of things like these here. If you short 230V to N/ground here, you will trip the breaker, and thats it. and breakers usually trip before you fire up a milimeter of wire.