AFCI and GFCI protection are two of the most important — and most confused — safety features in modern home electrical systems. Both are required by the National Electrical Code (NFPA 70), but they protect against completely different hazards. This guide explains exactly what each does, where each is required, and whether your home is up to code.
Contents
⚡ Key Takeaways
- AFCI breakers protect against arc faults that cause fires inside walls; GFCI protects against ground faults that cause electrocution.
- NEC code requires AFCI in most living spaces and bedrooms; GFCI is required in kitchens, bathrooms, garages, and outdoor areas.
- Dual-function AFCI/GFCI breakers provide both protections in one device and are required in many new installations.
What Is an AFCI?
An Arc Fault Circuit Interrupter (AFCI) is a circuit breaker that detects arc faults — dangerous sparking inside damaged or corroded wiring that ignites fires inside walls. Standard circuit breakers do not detect this low-level arcing. AFCI breakers use advanced electronics to cut power within milliseconds when an arc fault signature is detected.
The NEC requires AFCI protection in bedrooms, living rooms, kitchens, hallways, and most indoor living spaces in new construction and major renovations.
What Is a GFCI?
A Ground Fault Circuit Interrupter (GFCI) monitors current on the hot and neutral wires. If more than 5 milliamps leaks to ground — typically through a person — the GFCI trips in 1/40th of a second, fast enough to prevent lethal shock. GFCI protection can be an outlet (protecting downstream outlets) or a breaker protecting the full circuit.
NEC requires GFCI in kitchens, bathrooms, garages, crawl spaces, unfinished basements, outdoor outlets, and near pools.
AFCI vs GFCI: Key Differences
- AFCI prevents fires by detecting arc faults in wiring and devices.
- GFCI prevents electrocution by detecting current leaking through a person to ground.
- AFCI is always a breaker at the panel; GFCI can be an outlet or a breaker.
- AFCI does not protect against shock; GFCI does not protect against arc-fault fires.
Where Each Is Required by Code
AFCI (NEC 2020): All 120V, 15/20-amp branch circuits — bedrooms, living rooms, kitchens, hallways, garages, and most indoor areas.
GFCI (NEC 2020): Bathrooms, garages, crawl spaces, unfinished basements, outdoor receptacles, kitchen countertop outlets, laundry areas, and near pools. Local code varies — a licensed electrician can confirm your jurisdiction’s requirements.
Dual-Function AFCI/GFCI Breakers
Dual-function AFCI/GFCI breakers combine both protections in one panel device. They cost more than standard breakers but eliminate the need for separate GFCI outlets on the circuit and meet the most current NEC requirements. See our guide on resetting a tripped AFCI breaker.
Frequently Asked Questions
Can I replace a standard breaker with an AFCI breaker myself?
No. Circuit breaker replacement involves working inside an energized panel where main lugs remain live even with the main breaker off. This must be done by a licensed electrician.
Will an AFCI breaker nuisance-trip?
AFCI breakers can occasionally trip with older power strips or devices with filtering capacitors. Persistent unexplained trips usually indicate a wiring issue that needs an electrician to diagnose.
Do I need AFCI protection in an older home?
Code requirements apply to new construction and renovations, but retrofitting AFCI breakers into older homes is strongly recommended — older wiring is more prone to insulation degradation and arc faults.
How often should I test my GFCI outlets?
Test GFCI outlets monthly using the TEST button — the outlet should lose power. Press RESET to restore it. If the outlet fails to trip or won’t reset, it must be replaced immediately by a licensed electrician.