What is the time required for fire alarm secondary power to take over?

The correct answer is that the time required for fire alarm secondary power to take over is 10 seconds. This transition period is significant because it ensures that the fire alarm system remains operational during power interruptions. The secondary power source, often a battery or an uninterruptible power supply (UPS), is designed to activate quickly to maintain functionality and allow the system to continue monitoring and providing alerts in case of a fire emergency.

This 10-second timeframe is established in various codes and standards, such as those from the National Fire Protection Association (NFPA), which set guidelines to ensure that fire alarm systems are reliable and can effectively respond in emergencies. A shorter duration may not provide sufficient time for the backup systems to engage, while a longer duration could put lives and property at risk by delaying alarm signals when needed most.

The options are positioned in a way that reflects different potential timeframes, but the 10-second requirement is the standard that aligns with best practices for fire alarm systems, making it the accurate choice in this scenario.