Per NEC, the branch circuit for a fire alarm system is required to be supplied by which?

• A. Ground-fault circuit interrupters
• B. Arc-fault circuit interrupters
• C. Both a and b
• D. Neither a nor b

Answer: (D)

Fire alarm branch circuits are life-safety circuits. The NEC treats them differently from typical receptacle circuits because keeping the alarm system energized during an emergency is crucial. Ground-fault protection (GFCI) and arc-fault protection (AFCI) can cause nuisance trips or prevent alarms from sounding when faults occur, which would defeat the purpose of the system. For this reason, the branch circuit that feeds a fire alarm system is not required to have GFCI or AFCI protection; it uses standard overcurrent protection in accordance with the fire alarm installation rules (Article 760). So, neither GFCI nor AFCI protection is mandated for the fire alarm branch circuit.