What is the minimum size for multi-conductor fire related cable?

• A. 18 AWG
• B. 24 AWG
• C. 26 AWG
• D. 28 AWG

Answer: (C)

For fire-related multi-conductor cables, there is a required minimum conductor size to ensure reliable signaling and practical installation. The smallest gauge that meets that standard is 26 AWG. This size provides enough current-carrying capacity for the low-current signaling used in fire alarm circuits while allowing a compact jacket that can hold many conductors in a single cable. Using a smaller wire, like 28 AWG, would introduce too much resistance and potential voltage drop for the signaling currents, which can compromise performance. Larger gauges (such as 24 or 18 AWG) would still work but aren’t the minimum required; they’re simply bigger than necessary. So, 26 AWG is the minimum size that satisfies the fire-related cable requirement.