Screwdriver touches energized fuses, causing electric arc flash
Date of incident: July 2013
Notice of incident number: 2013160670173
Employer: Lumber mill
Incident summary
In a lumber mill, a maintenance worker was troubleshooting an electrical motor that had stopped working. The motor was rated for 575 volts. The worker shut off power to test three fuses. The fuses were functioning, but the motor still did not start when the power was turned back on. While the worker was standing beside an open compartment in an energized motor control centre, his screwdriver inadvertently made contact with the energized fuses and the bottom edge of the compartment frame. This contact resulted in an electric arc flash. The worker suffered arc flash burns to one side of his upper body. Another worker who was 15 feet (4.6 metres) away was temporarily blinded by the flash.
Cause
- Inadvertent contact with energized electrical equipment: The maintenance worker was working inside an open compartment in an energized motor control centre that supplies power to an electrical motor rated for 575 volts. His screwdriver inadvertently made contact with the energized fuses and the bottom edge of the compartment frame. The resulting electric arc flash melted the fuses in the compartment, and the worker suffered burns. The arc flash temporarily blinded another worker, who was approximately 15 feet (4.6 metres) away.
- Inadequate training: The maintenance worker had been provided informal and undocumented training regarding the testing and replacement of fuses. This training was not reviewed or approved by the British Columbia Safety Authority as required by law. Accordingly, this worker was not qualified to do this electrical work.
- Inadequate supervision: The supervisor had received the same informal, undocumented, and unapproved training for the testing and replacement of electrical fuses. He had various trades qualifications, but none of them qualified him to perform electrical work. Accordingly, the supervisor was not qualified to test or replace electrical fuses. He was not able to adequately articulate the safe work procedures for testing and replacing fuses. He was also unaware that written safe work procedures were available for this work. Accordingly, he was not able to properly supervise any worker conducting this electrical work.