Question 455Electricity & Electronics - QMED

The correct answer is B) general alarm and vital communication systems. The 24-volt DC bus on the emergency switchboard is typically used to supply power to essential safety and emergency systems, such as the general alarm and vital communication systems. These systems need to be powered even in the event of a main power failure, so the emergency switchboard provides a dedicated 24-volt DC power source to ensure their continued operation. The other options are incorrect because the main lighting system (A) and propulsion engine lube oil pump motors (C) are not considered essential safety or emergency systems, and the steering gear power unit motors (D) would typically be powered by the emergency switchboard's 440-volt AC bus.