In the event of power loss, how long shall a secondary power source for household...

Household fire alarm systems have different performance requirements from commercial systems, but still must support essential alarm functions under loss of primary power.

NFPA 72 (2022), Section 29.10.5.1.1:

“The secondary power supply shall be capable of powering the system under quiescent load for 24 hours and then capable of operating the system during alarm for a period of 4 minutes (for general fire alarm) or 10 minutes (for household fire alarm systems).”

Correct answer: C. 24 hours in the normal condition followed by 10 minutes of alarm

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