What is a notification appliance circuit (NAC) and which devices use it?

• A. A NAC powers audible and visual warning devices such as horns, bells, and strobes.
• B. A NAC powers HVAC components.
• C. A NAC provides data communication between panels.
• D. A NAC controls lighting circuits.

Answer: (A)

A notification appliance circuit is the dedicated low‑voltage path from the fire alarm control panel to the devices that warn occupants. It powers and signals the audible and visual warning devices, such as horns, bells, strobes, or speaker-strobes, so people hear and see an alarm.

This circuit is designed to provide enough current for all connected appliances and to be supervised so the panel can detect faults like open circuits or shorts. It’s separate from feeds for HVAC, data communications, or general lighting, which follow other systems. When an alarm activates, the panel sends power and signaling over the notification appliance circuit to drive the warning devices.