Abstract: AN EMPLOYEE WAS SETTING UP TO INSTALL STEEL STUDS ON A TOWER THAT HAD BEEN BUILT ON THE ROOF OF A BUILDING. HE HAD PLUGGED A TWO-POLE ATTACHMENT PLUG FOR A RADIO INTO A TWIST-LOCK CONNECTOR BUT HAD LEFT PART OF THE PLUG'S BLADES EXPOSED. THE GROUND-FAULT CIRCUIT INTERRUPTER PROTECTING THE CORD SET HAD BEEN WIRED OUT OF THE CIRCUIT AT THE TEMPORARY POWER SUPPLY BOX BY AN UNKNOWN PERSON. THE EMPLOYEE WAS USING AN ELECTRIC SCREW GUN TO INSTALL A STEEL STUD BASE CHANNEL. THE SCREW GUN WAS PLUGGED INTO THE SAME CORD AS THE RADIO. AS HE WAS WORKING, THE CORD MOVED, AND THE EXPOSED PART OF THE BLADE FOR THE UNGROUNDED CIRCUIT CONDUCTOR FOR THE RADIO CONTACTED THE BASE CHANNEL, ENERGIZING IT. WHEN THE EMPLOYEE, STANDING ON THE WET ROOF AND GROUNDED THROUGH THE EQUIPMENT GROUNDING CONDUCTOR ON THE SCREW GUN, BEGAN TO INSERT THE NEXT SCREW, HE RECEIVED AN ELECTRIC SHOCK AND WAS KNOCKED UNCONSCIOUS. THE EMPLOYEE WAS HOSPITALIZED FOR AN IRREGULAR HEARTBEAT.