Which battery capacity is required for a burglar alarm system to function correctly?

A burglar alarm system needs a sufficient battery capacity to ensure it remains operational during power outages. The correct answer indicates that a capacity to run for 24 hours under load is essential. This duration is typically considered standard because it allows the system to function through a day of power loss, which is a realistic period for restoration of electrical service.

A 24-hour capacity ensures that even in the event of a power failure, the alarm system can provide continuous protection, giving both time for utility repairs and peace of mind for homeowners or businesses. Systems designed with shorter capacity may risk becoming inoperative if outages exceed those durations, potentially leaving properties vulnerable.

In contrast, capacities longer than 24 hours, such as 48 or 72 hours, are generally not necessary for most residential or commercial applications and may lead to increased equipment costs or size without providing proportional benefits.