Lessons learned from an arc flash incident

While performing a routine startup of the electric prime mover at one of our stations, we had a breaker failure that resulted in an arc flash incident. The front door of the electrical cabinet and the rear cover both broke open allowing a 5´ fireball to escape into the compressor building. All station personnel were well outside the arc flash boundary, so they were not wearing any PPE during the start up. So went wrong? It was 15 degrees in the building when the operator was asked to bring the unit on, and the units had not been started in over 9 months. This paper will discuss the events that led to the arc flash incident, and what we did to remedy the problems at several of our compressor stations.