I am wondering what is being done by others when changing branch circuits from an older existing service over to a new install. Came upon a case where there was a fault to the armor of some old BX that never blew a fuse on the old service because the enclosure was never bonded to the neutral! Who knows how long it had been that way but on the new install the breaker tripped. What do you guys do for testing on old circuits before landing them in the new equipment?? Knob and tube can be a problem because of crossed neutrals buryied in the building somewhere...
