Within how many seconds must the secondary power supply automatically provide power to the protected premises fire alarm system when the primary power fails to provide the minimum voltage?

Within how many seconds must the secondary power supply automatically provide power to the protected premises fire alarm system when the primary power fails to provide the minimum voltage?

• A. 5 seconds
• B. 15 seconds
• C. 10 seconds
• D. 20 seconds

Answer: (C)

The system is designed to switch to backup power automatically as soon as the primary power no longer provides enough voltage. This automatic transfer keeps the fire alarm components—panel, detectors, initiating devices, and signaling circuits—operating without a gap, which is crucial for life-safety signaling during an outage. The standard timing for this transfer is ten seconds. That window balances avoiding unnecessary transfers from brief voltage dips with ensuring the system stays powered if the utility remains down, so there’s no momentary loss of alarms or other critical functions. The backup power source (often a rechargeable battery or dedicated standby supply) is sized to sustain the system, and the transfer occurs automatically to maintain continuous operation.

The system is designed to switch to backup power automatically as soon as the primary power no longer provides enough voltage. This automatic transfer keeps the fire alarm components—panel, detectors, initiating devices, and signaling circuits—operating without a gap, which is crucial for life-safety signaling during an outage. The standard timing for this transfer is ten seconds. That window balances avoiding unnecessary transfers from brief voltage dips with ensuring the system stays powered if the utility remains down, so there’s no momentary loss of alarms or other critical functions. The backup power source (often a rechargeable battery or dedicated standby supply) is sized to sustain the system, and the transfer occurs automatically to maintain continuous operation.