Doug,
I've been called out for everything from CATV guys, plumbers, drywallers, insulation shooters drilling through wires to a homeowner that was trying to hang something in his garage, not thinking about it., he drilled into his panel on the other side of the wall, through the can & into the bus!
It didn't damage the bus too bad ..(It seemed incinerating his drill bit cleared the fault before major bus damage occurred)
-Randy