Arc Flash During Battery Replacement (KV 133)

 

What Happened?

While changing out a battery in a safety system backup power bank, a short circuit occurred resulting in an arc flash and damage to several batteries. The electricians did not follow procedural guidance and did not insulate the inter-cell connector to eliminate the safety hazard. The electrician handling the cable assembly did not self-check and was not aware of the cable assembly’s close proximity to the inter-cell connector.

Contributing Factors

Design of the system and the tight working space created made it easy to cause a short circuit if proper insulation/cover was not installed.

What Can We Learn?

Tools

The use of Procedures would have required them to cover the connectors thus eliminating the hazard completely.

A Questioning Attitude by the workers, would have allowed them to evaluate the consequences vs. likelihood of performing this task without control measures in place.

Traps

The workers were Overconfident in there ability to deviate from procedures, and still perform the task safely.

The Physical Environment inside the battery compartment caused the workers to be in close proximity of energized equipment.

Ask the Right Questions

How does this relate to our work?

Where do we have similar traps?

What Tools can we use to avoid a similar incident?

Was a stop work point missed?