Given the following indications for an open 4,160 VAC breaker:
All phase overcurrent trip flags are reset.
The control power fuses indicate blown.
The line-side voltmeter indicates 4,160 VAC.
The load-side voltmeter indicates 0 VAC.
Assuming no operator actions were taken since the breaker opened, which one of the following could have caused the breaker to open?
A. A ground fault caused an automatic breaker trip.
B. A loss of control power caused an automatic breaker trip.
C. An operator opened the breaker locally at the breaker cabinet.
D. An operator opened the breaker remotely from the control room.
Show Answer
Answer: C
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