There wouldn't have been any chance to pull the main service fuse here, as this was on the feeder ahead of the meter panel. (In this case, there was an unusually long length of service cable inside the house structure.)
He'd built a new roof by laying rafters over the old ceilings, then realized all the cables (including the service feeder) were now trapped underneath the new timber. So he just notched the lower edge of each one for the cables before fixing the plasterboard over them.
The cable was the concentric type with neutral on the wire armor, so at least the screw he was touching made secure contact with the neutral before the point hit the live center conductor. It didn't take out any distribution fuses on the network - The feed was still live. It just vaporized the finely tapered end of the plasterboard screw.
[This message has been edited by pauluk (edited 12-04-2001).]
