NEC 210.12: Arc-Fault Circuit-Interrupter Protection
What This Article Covers
NEC 210.12 requires arc-fault circuit-interrupter (AFCI) protection on most 120-volt, single-phase, 15- and 20-ampere branch circuits supplying outlets and devices in dwelling unit kitchens, family rooms, bedrooms, hallways, and similar spaces. AFCIs detect dangerous arcing faults that ordinary breakers cannot.
Key Requirements
- AFCI protection required in: kitchens, family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas, and similar rooms (210.12(A))
- Combination-type AFCI protection is required
- AFCI may be provided by an AFCI circuit breaker or by listed outlet branch-circuit AFCI device installed at the first outlet
- Bathrooms, garages, and unfinished basements have separate requirements (210.8 GFCI rather than AFCI in most cases)
- The branch-circuit conductors from the AFCI device must be installed inside the enclosure or in metal raceway/cable
Common Field Applications
- Replacing a tripped AFCI breaker — verify with a known AFCI tester first
- Adding a circuit to a remodeled bedroom — AFCI required
- Troubleshooting nuisance trips on shared neutral (multi-wire branch circuits with AFCI need two-pole AFCI breaker)
Common Mistakes & Inspection Failures
- Installing a standard breaker after replacing a tripped AFCI — code violation
- Sharing neutrals across two AFCI single-pole breakers — must be two-pole
- Forgetting AFCI on extension or modification of existing circuits in dwelling areas
Related NEC Articles
Have a specific question about NEC 210.12?
Ask Sparky AI for a plain-English answer with citation.
Ask Sparky AIFrequently Asked Questions
What does NEC 210.12 cover?
NEC 210.12 requires arc-fault circuit-interrupter (AFCI) protection on most 120-volt, single-phase, 15- and 20-ampere branch circuits supplying outlets and devices in dwelling unit kitchens, family rooms, bedrooms, hallways, and similar spaces. AFCIs detect dangerous arcing faults that ordinary breakers cannot.
What are the key requirements of NEC 210.12?
Key requirements include: AFCI protection required in: kitchens, family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas, and similar rooms (210.12(A)); Combination-type AFCI protection is required; AFCI may be provided by an AFCI circuit breaker or by listed outlet branch-circuit AFCI device installed at the first outlet. See the full requirements list on this page.
What are common mistakes with NEC 210.12?
Installing a standard breaker after replacing a tripped AFCI — code violation Sharing neutrals across two AFCI single-pole breakers — must be two-pole Forgetting AFCI on extension or modification of existing circuits in dwelling areas
Related Resources
Michael B.
IBEW Local 134 Journeyman Electrician · Licensed Electrical Contractor
Michael is an IBEW Local 134 journeyman and licensed electrical contractor. He teaches federal pre-apprenticeship on the south side of Chicago, helping students get into the IBEW. He built this practice test because he knows exactly what the NJATC aptitude exam tests — and what trips people up. If you prep with this, you walk in ready.