After a black out onboard and once ships power has been restored, the engine room supply fans must be started manually. What characteristic of the electrical circuit for the supply fans cause this requirement?

Correct Answer: Option D — The circuit for the supply fan is wired for low voltage protection.

Low voltage protection (LVP) circuits utilize a magnetic contactor that drops out when voltage fails. Unlike low voltage release, LVP requires a manual restart after power restoration because the control circuit is interrupted, preventing automatic, potentially hazardous, restarts of machinery when the ship's power is restored following a blackout.