Abstract: An employee was replacing 60-ampere fuses in a disconnect box on a 480-volt busway. The disconnect was defective, and the circuit was still energized even when the disconnect's cover was opened. Additionally, the 600-ampere circuit breaker protecting this busway was deliberately blocked; thus, the breaker could not trip when an overload occurred.. As the employee, who did not test the circuit before beginning work, was replacing the fuses, an electrical fault occurred. The employee sustained severe burns as a result of the ensuing electric arc. He was hospitalized for his injuries, but died following surgery 2 days after the accident.