Upon failure of the ships normal electrical power supply, by means of what device does the emergency generator supply power to the emergency switchboard, but not the main switchboard?

Correct Answer: Option C — automatic bus transfer switch

Per 46 CFR 112.05, upon a loss of normal ship's service power, an automatic bus transfer (ABT) switch or emergency power source automatically energizes the emergency switchboard. This ensures uninterrupted power delivery to critical safety loads while maintaining absolute isolation from the dead main bus.