Abstract: A journeyman electrician for an electrical contractor was replacing a circuit breaker in a panelboard. The panelboard was over 30 years old. The electrician, who had 8 years of experience, had performed this task thousands of times in the past. The bus in the panelboard was held by two screws: one at the top and one at the bottom. The employee unscrewed the bottom screw. Unfortunately, the top of the bus was loose, and it rotated against another bus when the bottom screw was loosened. The resulting electrical fault caused an electric arc, which burned the employee (who was not wearing any eye protection) on the face and hands. The employee spent 24 hours in intensive care at a hospital, before he was transferred to the trauma ward.