Incidently this is how I found my FPE breakers dont always trip.

turned off what I thought was the right breaker in the middle of a job,
pushed the 2 wires together, they sparked, stuck together, and
literally fried. length turned brite red and blew apart. the short
loaded down the neighborhood, my neighbor was running a circular saw,
it quit during the short. my neighbor saw the flash and came over and
asked you still alive I was working in my garage, adding a outdoor
light.

You try your best but when doing jobs things happen....