What is the minimum size grounding conductor that can be used when wiring a fire alarm control panel to a 20 amp breaker?

What is the minimum size grounding conductor that can be used when wiring a fire alarm control panel to a 20 amp breaker?

• A. 10 AWG
• B. 14 AWG
• C. 16 AWG
• D. 12 AWG

Answer: (D)

Grounding conductors are sized based on the overcurrent protection protecting the circuit. The NEC rule for equipment grounding conductors (250.122) matches the conductor size to the OCPD rating. For a 20-amp circuit, the minimum copper grounding conductor size is 12 AWG. Using a smaller size like 14 AWG or 16 AWG would not meet the requirement for a 20A circuit, even though those gauges are common on lower-amp circuits. The larger 12 AWG provides a low enough impedance path for fault currents to trip the breaker reliably. So, the smallest acceptable copper grounding conductor for a fire alarm control panel on a 20-amp breaker is 12 AWG.

Grounding conductors are sized based on the overcurrent protection protecting the circuit. The NEC rule for equipment grounding conductors (250.122) matches the conductor size to the OCPD rating. For a 20-amp circuit, the minimum copper grounding conductor size is 12 AWG. Using a smaller size like 14 AWG or 16 AWG would not meet the requirement for a 20A circuit, even though those gauges are common on lower-amp circuits. The larger 12 AWG provides a low enough impedance path for fault currents to trip the breaker reliably. So, the smallest acceptable copper grounding conductor for a fire alarm control panel on a 20-amp breaker is 12 AWG.