Standby Power is used to supply backup power to which functions?

• A. Lighting Systems
• B. Main Motors
• C. Emergency signaling and communication devices
• D. Primary Controls

Answer: (C)

Standby power is meant to keep the safety-critical systems running when normal power is lost. The priority in an outage is to alert passengers and maintain communication with staff and responders, so the backup power is devoted to emergency signaling and communication devices. These devices—alarms, intercoms, and status indicators—allow people to be warned and coordinated during an outage, which is essential for safe evacuation and response. Powering main motors or primary controls would be dangerous and unnecessary during a loss of power, and while lighting can be helpful, it’s the signaling and communication capability that must remain active to ensure safety.