The 2020 NEC requires arc-fault circuit interrupter (AFCI) protection on 120-volt, 15 A and 20 A circuits in most rooms of a house. That includes kitchens, bedrooms, living rooms, closets, hallways and laundry areas. Bathrooms, garages and outdoor areas are not on the list.
An AFCI shuts off a circuit when it detects arcing, like a loose splice or a nail through a cable. It must be readily accessible. The rule says "outlets or devices," so lights and switches count. A bedroom lighting circuit needs AFCI even with no receptacles.
| Quick facts | AFCI in the 2020 NEC |
|---|---|
| Circuits covered | 120 V, single-phase, 15 A and 20 A branch circuits. 240 V circuits are not covered. |
| Dwellings (210.12(A)) | Kitchens, family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas and similar rooms |
| Dormitories (210.12(B)) | Bedrooms, living rooms, hallways, closets, bathrooms and similar rooms |
| Hotels and care facilities (210.12(C)) | Hotel and motel guest rooms and suites, and patient sleeping rooms in nursing homes and limited-care facilities |
| Old wiring changed (210.12(D)) | Modified, replaced or extended circuits in those areas need AFCI. Extensions of 6 ft or less with no new outlets are exempt. |
| Receptacle swaps (406.4(D)(4)) | A replaced receptacle in those areas needs AFCI protection. The 6 ft exception doesn't apply. |
Six ways to provide AFCI protection, 210.12(A)
Most jobs use method 1. Methods 2 through 6 put an outlet branch-circuit (OBC) AFCI, an AFCI receptacle, at the first outlet. Each protects the home run (panel to first box) another way.
- Combination-type AFCI breaker protecting the whole branch circuit.
- Branch/feeder AFCI breaker plus an OBC AFCI. Mark the first outlet box.
- Supplemental arc protection breaker plus an OBC AFCI. Continuous home run, no longer than 50 ft for 14 AWG or 70 ft for 12 AWG. Mark the first outlet box.
- Standard listed breaker plus an OBC AFCI. Same rules as method 3, and the pair must be listed as a system combination-type AFCI.
- Metal home run plus an OBC AFCI. Metal raceway, metal wireway, metal auxiliary gutter, or Type MC or AC cable that qualifies under 250.118, with metal boxes.
- Concrete-encased home run plus an OBC AFCI. Listed conduit or tubing, or Type MC cable, under at least 2 in. of concrete.
Fire alarm exception: a fire alarm system's individual branch circuit can skip AFCI. It must be in metal raceway, metal auxiliary gutter, steel-armored cable, or Type MC or AC cable with metal boxes.
Exam questions often pair 210.12 and 406.4(D). Tab both in your 2020 NEC softbound book.
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What changed in the 2020 NEC AFCI requirements?
- Care facilities added to 210.12(C): patient sleeping rooms in nursing homes and limited-care facilities. 2017 covered only hotel and motel guest rooms and suites.
- Guest rooms added to 210.12(D): 2017 covered only dwelling and dormitory units.
- More options for old wiring: 2017 allowed a combination AFCI at the origin or an OBC AFCI at the first receptacle. 2020 allows any of the six methods, or the OBC AFCI at the first receptacle.
- Clearer 6 ft exception: splicing devices are allowed. Wire inside an enclosure, cabinet or junction box doesn't count toward the 6 ft.
Worked example: a new house and a remodel
New house: which circuits need AFCI?
| Circuit | AFCI? Why |
|---|---|
| 20 A kitchen countertop circuits | Yes. Kitchen is listed. They also need GFCI, so use a dual-function breaker or an AFCI breaker with GFCI receptacles. |
| 20 A dishwasher circuit | Yes. Kitchen is listed. GFCI applies too. |
| 20 A laundry circuit | Yes. Laundry areas are listed. GFCI applies too. |
| 15 A bedroom lights and receptacles | Yes. Bedrooms are listed. |
| 20 A bathroom receptacle circuit | No. Bathrooms aren't on the dwelling list. GFCI is still required. |
| 20 A garage receptacles | No. Garages aren't listed. GFCI is still required. |
| 30 A, 240 V dryer circuit | No. AFCI covers only 120 V, 15 A and 20 A circuits. |
For the GFCI side, see JCR's 2020 GFCI requirements guide.
Remodel: extending and replacing
- Adding two receptacles to a bedroom circuit: AFCI required, 210.12(D). Any 210.12(A) method works, or an OBC AFCI at the first receptacle outlet.
- Extending a bedroom home run 4 ft to a relocated panel, splice only: no AFCI. It's under 6 ft with no new outlets.
- Replacing a living room receptacle: the new one needs AFCI protection, 406.4(D)(4).
- Method 3 or 4 with a 60 ft home run: OK for 12 AWG (70 ft), not 14 AWG (50 ft).
Common AFCI exam traps
- Swapping the length limits. 50 ft goes with 14 AWG, 70 ft with 12 AWG.
- Forgetting to mark the first outlet box in methods 2, 3 and 4.
States often amend AFCI rules, and not every state is on the 2020 NEC. Check JCR's state requirements page.
AFCI requirements questions
Do bathrooms need AFCI protection in the 2020 NEC?
Not in dwelling units. Section 210.12(A) doesn't list bathrooms, though they still need GFCI. Dormitory bathrooms are listed in 210.12(B), so they do.
Does a garage need AFCI under the 2020 NEC?
No. Garages aren't on the 210.12(A) list, so they need GFCI but not AFCI. A circuit that also feeds a hallway or other listed room does need AFCI.
Do I need AFCI when I replace a receptacle?
Yes, in an area 210.12(A), (B) or (C) covers. Section 406.4(D)(4) requires an AFCI receptacle, a receptacle protected by one upstream, or a combination AFCI breaker. The 6 ft exception doesn't apply.
Can the AFCI be at the first outlet instead of the panel?
Yes. Methods 2 through 6 put an outlet branch-circuit AFCI there. The home run is protected by a length limit, metal wiring or concrete encasement instead.
Do kitchen countertop circuits need both AFCI and GFCI?
Yes. The kitchen is on the AFCI list, and countertop receptacles are on the GFCI list. Use a dual-function breaker, or an AFCI breaker with GFCI receptacles.
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Related guides: GFCI requirements (210.8) · Dwelling service load calculation · Closet light clearance (410.16(C))
More worked examples: all NEC Answers.
References
- NFPA 70, National Electrical Code, 2020 edition
- 2020 NEC 210.12(A) through (D)
- 2020 NEC Article 100, AFCI definition
- 2020 NEC 406.4(D)(4), replacement receptacles
- 2020 NEC 250.118, equipment grounding conductor types
- 2017 NEC 210.12, for the 2020 changes
JCR checked every AFCI rule above against the 2020 and 2017 NEC in NFPA LiNK on October 14, 2026.