LEE DAVIS ELECTRIC, INC.

ELECTRIC SHOCK - GROUND FAULT IN CONVEYOR CIRCUIT

A JOURNEYMAN ELECTRICIAN WAS TROUBLESHOOTING A 480-VOLT CONTROL CIRCUIT FOR A CO NVEYOR SYSTEM. THE CONVEYOR WAS USED TO RECEIVE AND PILE POTATOES AT A WAREHOUSE . THE ELECTRICIAN HAD REPLACED THREE MALFUNCTIONING COMPONENTS AND HAD RECONNECT ED THE PLUG ON THE CONVEYOR'S POWER SUPPLY CABLE. HE THEN WENT TO THE CONTROL ST ATION AT THE RECEIVING END OF THE CONVEYOR AND GRABBED THE HAND GRIP THAT WAS PR OVIDED TO AID EMPLOYEES CLIMBING ONTO THE CONTROL PLATFORM. HE WAS ELECTROCUTED AS HE TOUCHED THE HAND GRIP. (THE CONVEYOR, WHICH WAS MOUNTED COMPLETELY ON RUBB ER TIRES, WAS ISOLATED FROM GROUND.) INVESTIGATION REVEALED THAT A GREEN-COLORED CONDUCTOR HAD BEEN USED AS A 277-VOLT CIRCUIT CONDUCTOR. AN UNSKILLED EMPLOYEE HAD ERRONEOUSLY CONNECTED THIS CONDUCTOR TO TWO GREEN EQUIPMENT GROUNDING CONDUC TORS WITH A WIRE NUT AS HE WAS REPLACING A DAMAGED JUNCTION BOX. THE EQUIPMENT G ROUNDING CONDUCTORS WERE CONNECTED TO THE FRAME OF THE CONVEYOR. WHEN THE CONVEY OR WAS ENERGIZED, THIS GROUND FAULT ALSO ENERGIZED THE CONVEYOR'S FRAME.