What is the function of a transfer switch in fire alarm power systems?

• A. It switches the system from normal mains to battery backup automatically when mains fail.
• B. It monitors smoke levels.
• C. It calibrates detectors.
• D. It alerts the building management.

Answer: (A)

Maintaining uninterrupted power is essential for fire alarm reliability. A transfer switch automatically detects loss of mains power and connects the system to the backup power source (battery or generator), keeping the control panel, detectors, and notification devices powered. This seamless handoff ensures the system continues to operate during an outage, so warnings and monitoring aren’t interrupted. It’s not involved in sensing smoke, calibrating detectors, or alerting building management; those functions are handled by detectors and the control panel. The transfer switch’s role is strictly to manage power sources to maintain continuous operation.