Safety Information Alert

1. Safety Information Alert Arc Flash Incident at a Duke Energy facility

2. 2300 Volt Switchgear Breaker Failure December 17, 2009

3. Incident Details • 2300 volt switchgear breaker failure • The injured worker was assisting another worker restoring service to an air compressor. • They racked in a 2300 volt breaker when it failed catastrophically • The injured employee was not wearing flame retardant clothing. His clothing ignited and he was burned seriously. • Another worker in front of the cubicle was not injured. He was wearing an arc flash coat, face shield and electrical gloves.

4. Investigation of the cause of the equipment failure is continuing. Preliminary results indicate that the breaker was in the "closed" position and the interlocks failed to work properly when it was inserted onto the energized bus, causing the failure.

5. Front of switchgear

6. Side of switchgear

7. Inside of switchgear

8. Lessons Learned: • Use of arc flash protection for work on switchgear and motor control centers. Refer to specific procedures for personal protective equipment for racking switchgear breakers. At the plant where this occurred, typically, racking a 2300 volt breaker requires use of a flash suit, beekeeper type hood with face shield, rubber gloves with leather protectors, hard hat, and safety glasses.

9. Lessons Learned: • Arc flash procedures require that all employees within the flash boundary wear arc flash protective equipment.

10. Lessons Learned: • Pre-job briefings for work on switchgear breakers must include a detailed discussion of protective equipment requirements, establishment of safe work boundary, and actions to be taken to keep unprotected persons outside the boundary.

11. Lessons Learned: • Prior to racking a breaker in, workers should always verify that the breaker is in the open position.