Arc-fault (AFCI) protection in homes

What the code requires

210.12(B): In dwelling units, 120 V single-phase branch circuits rated 10, 15 or 20 A that supply outlets or devices in these areas need AFCI protection: bedrooms, living rooms, family rooms, dining rooms, kitchens, dens, libraries, parlors, sunrooms, recreation rooms, hallways, closets, laundry areas and similar areas. AFCIs must be listed and installed in a readily accessible location.

210.12(A) lists the allowed means of protection. One is a combination-type AFCI circuit breaker. Others pair a branch/feeder AFCI breaker or a supplemental arc-protection breaker with an outlet-type AFCI at the first outlet, which must be marked. With a supplemental breaker, or with a system-combination outlet AFCI, the wiring to the first outlet must be continuous and no longer than 50 ft for 14 AWG or 70 ft for 12 AWG.

An outlet-type AFCI at the first outlet is also allowed where the home run is in metal raceway, Type MC cable or Type AC cable with metal boxes, or is encased in at least 2 in. of concrete.

210.12(E): When a circuit in one of these areas is modified, replaced or extended, it must be protected by one of the 210.12(A) methods or by a listed outlet-type AFCI at the first receptacle outlet of the existing circuit.

On the job

• Under this rule, AFCI protection is not required in dwelling bathrooms, garages or outdoors.
• Extending a bedroom circuit by more than 6 ft, adding an outlet to it, or modifying or replacing its wiring triggers AFCI protection under 210.12(E).
• Older checklists cite 210.12(D) for the extend-or-modify rule. In the 2023 NEC that rule is 210.12(E).
• Dormitories and other occupancies have their own AFCI rules in 210.12(C) and (D), including sleeping quarters in fire, police, EMS and ranger stations.

Exceptions that matter

• A dedicated fire-alarm circuit installed in metal raceway, Type MC, Type AC or steel-armored cable with metal boxes.
• An extension of 6 ft or less that adds no outlets or devices other than splicing devices does not trigger 210.12(E). Conductors inside enclosures do not count toward the 6 ft.

What changed in 2023

The 2023 edition reorganized the section, moving the extend-or-modify rule from 210.12(D) to 210.12(E), added 10 A circuits, and added sleeping quarters in fire, police, EMS and ranger stations under 210.12(D)(3).

Related sections

• NEC 210.8(A): GFCI protection in homes
• NEC 406.4(D)(4)
• NEC 760.41(B)
• NEC 760.121(B)

Where this comes from

• Mike Holt: Changes to the NEC 2023, 210.12
• NFPA: NFPA 70 2026-cycle First Draft, CMP-2 (2023 baseline text)
• IAEI Magazine: It's Time to Allow More Ways for AFCIs to Protect Us (Dec 27 2023)
• Oregon BCD: 2023 Oregon Electrical Specialty Code, Table 1-E (2023 NEC text)
• Read the official NEC free at NFPA