Malfunction of an FFTF diesel generator. Final unusual occurrence report

The diesel generator output breaker (B4A-02) closed on an energized bus after malfunction of diesel generator No. 1 switchgear circuits. An Operations Test Procedure was in progress to measure the diesel engine oil pressure. The engine was manually started per the operating procedure. The engine came up to a speed normally and then started to coast down in speed until it stopped. During this time an operator attempted to restart the engine, but it would not restart due to an expected low lube oil alarm. Several minutes after the startup was attempted, the operator noted that both the open and closed indicating lights for the diesel generator output breaker were lit. The operator moved the breaker remote control switch from the after-trip to the trip position and nearly simultaneously noted the bus voltage increase from approximately 300 volts to 480 volts and the closed light go out. The normal bus voltage is 480 volts