Question 279Electricity & Electronics - 1st Asst/Chief

The correct answer is A) The 24 volt DC bus. The 24 volt DC bus is typically used to supply power for alarm signals under emergency conditions on a vessel's emergency switchboard. This is because the 24 volt DC system is designed to be highly reliable and redundant, ensuring that critical safety systems like alarms remain functional even in the event of a total loss of the main electrical power. The other options are incorrect because the 120 volt, 60 cycle, 3 phase bus and the 450 volt, 60 cycle, 3 phase bus are typically used to distribute main electrical power, not emergency power for alarms. The generator and bus transfer section is responsible for automatically transferring the vessel's electrical load to the emergency generator in an emergency, but does not directly power the alarm systems.