First fire I ever investigated was a 120 V two wire system in a vacant house.
The neutral leg was grounded inside the house. It was all piped in old black iron rigid pipe. The service drop went to a Tee condulet with one leg to the meter and back and the other to the panel. The insulation failed at the Tee and energized the pipe all the way through the house. Chared every stud it was attached to. Fire Dept. was called when the drop melted and fell into the yard causing sparks and arcs.
Fire Dept claimed the arcing in the yard caused the house to burn. Meter had been pulled for six months. After I detailed how it really happened they started calling me to help them with fire investigations.
Only good news was that on all two wire services after that the utility would pull the meter and cut it at the pole.
Alan--
"Only thing I don't understand about electricity is why more people don't die each year." Hogan, Chief Inspector, City of Chicago 1982, IAEI meeting.
