NEC 210.12 — AFCI Protection Requirements
Arc-fault circuit-interrupter (AFCI) protection is required for 120V, 15A and 20A branch circuits supplying outlets or devices in the areas listed below for dwelling units. Parallel arc-fault detection helps prevent electrical fires from damaged, deteriorating, or overloaded wiring.
210.12(A) — Dwelling Units
All 120V, 15A and 20A branch circuits supplying outlets and devices installed in any of the following rooms or areas of a dwelling unit shall be protected by a listed combination-type AFCI located at the origin of the branch circuit.
210.12(B) — Dormitory Units
All 120V, 15A and 20A branch circuits supplying outlets and devices installed in any of the areas specified in 210.12(A) in dormitory units shall have AFCI protection.
210.12(C) — Guest Rooms and Guest Suites (Hotels, Motels)
Required for all 120V, 15A and 20A branch circuits supplying outlets in sleeping rooms and similar areas within guest rooms or suites of hotels and motels, as listed in 210.12(A).
Permitted AFCI Protection Methods
- Combination-type AFCI breaker — most common method; protects the entire branch circuit from the panel.
- Outlet branch-circuit AFCI (OBC AFCI) — permitted when installed at the first outlet, with maximum 6 ft of wiring from panel to first outlet (see 210.12(A) exception for extensions in existing buildings).
- AFCI receptacle or device — can provide downstream protection; must be combination-type per latest cycles.
Key Exceptions
- • Extensions in existing buildings: when adding or extending circuits, an OBC AFCI at the first outlet is an acceptable alternative to a panel breaker.
- • Metal-clad cable (MC) or rigid metal conduit (RMC): the metallic sheath provides arc containment; see specific exceptions for length limitations and conduit types.
- • Not required for: circuits supplying fire alarm systems (see Article 760), or circuits in healthcare facilities where alternate protection methods are provided.
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