In a fire alarm system, what is the minimum size for single conductors?

The minimum size for single conductors in a fire alarm system is 18 AWG. This standard is mainly established to ensure sufficient current-carrying capability and to minimize resistance along the wire, maintaining reliability and effectiveness in a fire alarm system's operation. Using 18 AWG wire helps ensure that data signals are transmitted effectively across the system without interference or significant signal loss, which is crucial in emergency situations where every second counts.

While larger gauge wires like 16 AWG can carry more current and may be used in some applications where higher power is needed, the 18 AWG size is an established minimum that balances between adequate performance and usability in typical fire alarm scenarios. Smaller gauges such as 20 AWG or 22 AWG may not meet the necessary requirements for fire alarm systems, potentially leading to issues in sound transmission or circuit functionality during a fire emergency. Thus, 18 AWG signifies a reliable choice in safety-critical installations.