Abstract: On August 6, 2006, Employee #1, a certified electrician, and a helper, were repairing an energized three-phase, 480-volt AC circuit. When the final circuit conductors were being connected at the control panel, the ground wire was accidentally shorted directly to the phase terminals, creating an arc fault and flash. The blast of released energy struck Employee #1 full force; he suffered serious injuries that eventually resulted in his death. The coworker was knocked down and suffered contusions and abrasions, along with a headache and a temporary loss of hearin. Subsequent investigation determined that the circuit was energized unnecessarily, no form of personal protective equipment was being used, and no insulating materials/shields or devices were in place to protect from such accidental contacts. The panel was not appropriately marked for arc fault/flash hazards, and no form of warning, such as barriers, signs or symnols) were in place.