Abstract: A MAINTENANCE EMPLOYEE WAS REPLACING A HYDRAULIC CYLINDER ON THE BOOM OF A PACK-A-BACK. THIS EQUIPMENT IS HEAVY MACHINERY WITH A GRAPPLE ATTACHMENT ON ITS BOOM, AND IT IS USED TO MOVE LOGS. THE HYDRAULIC CYLINDER WAS BEING HELD IN PLACE WITH A SMALL ELECTRIC HOIST MOUNTED ON AN OVERHEAD BRIDGE. THE 16-INCH ELECTRIC SUPPLY CORD FOR THE HOIST HAD A CORD CONNECTOR ON ITS END RATHER THAN AN ATTACHMENT PLUG. IT WAS CONNECTED TO A TWIST-LOCK ATTACHMENT PLUG ON THE END OF A SPRING-LOADED CORD REEL THAT WAS 10 FEET ABOVE THE FLOOR AND THAT HAD BEEN WIRED (BY AN ELECTRICIAN) TO A 480-VOLT SUPPLY CIRCUIT. (THE HOIST WAS "NEVER" UNPLUGGED.) THE EMPLOYEE WAS STRADDLING THE BOOM AND WAS LEANING ON THE BOOM TRYING TO PRY THE CYLINDER INTO PLACE. THE MOVEMENTS OF HIS BODY OVER THE CORD CAUSED THE TWIST-LOCK ATTACHMENT PLUG TO BECOME DISCONNECTED. THE ENERGIZED ATTACHMENT PLUG ON THE END OF THE CORD REEL FELL ONTO THE EMPLOYEE'S BODY AND ELECTROCUTED HIM.