Branch Circuits

210.12 Arc-Fault Circuit-Interrupter (AFCI) Protection

The word "receptacle" was deleted and the words “listed device that protects the entire branch circuit” were added. This subsection now reads:

(A) AFCI Definition. An AFCI protection device provides protection from an arcing fault by recognizing the characteristics unique to an arcing fault and by functioning to de-energize the circuit when an arc fault is detected.

(B) Dwelling Unit Bedrooms. AAll branch circuits supplying 15 or 20A, single-phase, 125V outlets installed in dwelling unit bedrooms must be AFCI protected by a listed device that protects the entire branch circuit. Figure 210–4

Intent: The change extends AFCI protection to all branch circuit conductors that supply 125V outlets in dwelling unit bedrooms, whereas the 1999 NEC only required AFCI protection for all branch circuits conductors that supply 15 or 20A, single-phase, 125V receptacle outlets in dwelling unit bedrooms. Currently there are three types of AFCI protection devices.

AFCI Branch/Feeder Type (AVZQ) – This protection device is typically has the AFCI protection integral with a circuit breaker. It is designed to protect the branch circuit wiring against the unwanted effects of arcing, with limited protection to power supply cords connected to the receptacle.

AFCI Outlet Branch Circuit Type (UL – AWBZ) – This AFCI protection device is typically a receptacle with integral AFCI protection that is intended to protect both the power supply cords connected to the receptacle and the upstream branch circuit wiring.

AFCI Outlet Type (UL – AWCG and AWBZ) – This device is likely to be a receptacle with integral protection that is designed to protected cord sets plug into it, not the upstream branch circuit wiring.

Author’s Comment: At the time a dwelling unit is wired, it is hard to tell from looking at the bare walls whether a room will be used as a home office or a bedroom. Also, if you are looking at an efficiency apartment, a room may well be furnished with a foldout couch that is used for sleeping on every night, making it look as much like a bedroom as a living room.

If you wire bedroom branch circuits with one circuit for lighting and receptacles, this change will have little effect. But the practice of separating the lighting from the receptacle circuits in dwelling unit bedrooms will now require two AFCI circuit breakers. The 125V limitation to the requirement means that AFCI protection would not be required for a 240V baseboard heater or room air conditioner.