Storage batteries shall have sufficient capacity to operate a proprietary burglar alarm system under maximum intended load for a period of?

• A. 12 hours
• B. 24 hours
• C. 48 hours
• D. 72 hours

Answer: (B)

Standby power duration is about how long the backup batteries must keep the system running if the main power fails. A proprietary burglar alarm system draws power from the control panel, sensors, and annunciation devices, so the battery must be able to supply the entire load for a set time. The requirement specifies twenty-four hours, ensuring the system remains operational after a outage long enough to maintain monitoring and reporting while power is restored or a repair is made. If the duration were shorter, the system might lose functionality during longer outages; if it were much longer, it would add unnecessary cost since twenty-four hours meets typical reliability needs.