What gauge wire should be used to ground a fire alarm panel?

• A. 12 AWG
• B. 14 AWG
• C. 16 AWG
• D. 18 AWG

Answer: (D)

Grounding a fire alarm panel involves providing a reliable reference path for the panel’s low-voltage signaling circuitry, not carrying heavy fault currents like the building’s main power ground does. The ground for these low-voltage circuits is typically a short, dedicated control ground that only needs to reference the 24-volt system and keeps noise and stray currents from affecting operation. Because the current in these control and signaling paths is limited by the power supply and devices, a smaller conductor such as 18 AWG is sufficient and practical to install. Using a larger gauge would add cost and unnecessary bulk without improving safety for this specific ground path. The main equipment grounding conductor for the power circuit remains sized per the overcurrent protection and is part of the building’s electrical grounding system, separate from the panel’s low-voltage ground reference. So, 18 AWG is the typical choice for grounding the fire alarm panel’s low-voltage circuitry, provided it complies with manufacturer guidance and applicable codes.