Inspection Detail

Inspection: 119617454 - Pg & E

Inspection Information - Office: San Francisco District Office

Investigation Summary

On the morning of March 17,1995, a substation electrician for an electric utility noticed that a disconnect appeared to have a loose coupling on its vertical operating rod. This defect prevented the disconnects from closing. The electrician adjusted the coupling, but the problem was corrected on only one of three phases. Later that day, two other electricians were assigned to work on the coupling. At 3:00 PM, the electricians requested an aerial lift truck to assist them in their work. The aerial lift was positioned near a deenergized conductor between the bottom of one open disconnect and the bushings on another disconnect. The employees would ground the deenergized conductors, adjust the horizontal inter-phase linkage, lower the aerial lift bucket, remove the grounds, and operate the disconnect to check for proper adjustment. They repeated this procedure several times. The employees then left the disconnect in a closed position to determine what the next adjustment should be. One of the electricians observed the disconnect from the bucket and asked the other electrician to ground just one of the phase conductors. Without checking the position of the disconnect and without checking for voltage on the conductors, the second electrician applied a ground to the energized, 12-kilovolt conductor. This caused an electrical fault, and the ensuing electric arc burned both employees. One of the employees was hospitalized with severe burns to his face, neck, and shoulder. Since no customers would have been affected, the employees could have performed the work with the entire circuit deenergized. However, they chose to work it energized.

Keywords: BURN, CLOTHING, ELECTRIC ARC, ELECTRICAL, ELECTRIC SWITCH, POWER LINE WORKER, E PTD, SUBSTATION, ELEC UTILITY WORK, ELECTRICAL FAULT