Electrical Maintenance personnel were in the process of removing temporary power feeds. As part of the process of removing the temporary power, electricians were required to remove a temporary Plexiglas cover. The spring loaded retaining nuts had to be accessed via small holes drilled through the Plexiglas cover. As the Electrician was attempting to disengage the spring loaded nut, the screwdriver (~8 inches) drifted off of the nut, went through a small gap on the side of the bus bar guard, and made contact with a live 277V bus bar, causing electrical arcing and the trip of the feed breaker. The Electrician performing the work was wearing the appropriate PPE for the task and was not injured during this event.
The risk of working on energized equipment was not recognized during the work planning process, pre-job brief, and/or 2-Minute Drill, and the proper tool was not used to disengage the spring nuts.
What Can We Learn?
A Questioning Attitude would have helped identify the risk associated with this task and ways to mitigate it.
The need to perform this task on energized equipment, elevated the risk associated with it. (Physical Environment)
Overconfidence may have been a factor as this appeared to be a routine/simple task.
Ask the Right Questions