When the BATT master switch is on, which bus powers the fire protection system?

When the BATT master switch is on, which bus powers the fire protection system?

• A. AC bus
• B. DC battery bus
• C. DC emergency bus
• D. DC essential bus

Answer: (B)

When the BATT master switch is on, the battery’s power is routed to the DC power distribution that is tied directly to the battery bus. The fire protection system is wired to this DC battery bus so it can operate on battery power even if generators or other power sources are lost. This guarantees the system remains powered during electrical faults, ensuring fire detection and extinguishing capability is always available. The other buses rely on different sources or configurations and aren’t designed to provide immediate battery-only power for the fire protection system, which is why the direct battery bus is the correct supply.

When the BATT master switch is on, the battery’s power is routed to the DC power distribution that is tied directly to the battery bus. The fire protection system is wired to this DC battery bus so it can operate on battery power even if generators or other power sources are lost. This guarantees the system remains powered during electrical faults, ensuring fire detection and extinguishing capability is always available. The other buses rely on different sources or configurations and aren’t designed to provide immediate battery-only power for the fire protection system, which is why the direct battery bus is the correct supply.