GFCI vs AFCI: Differences and Where Each Is Required
Chameera Sampath · 10/18/2026
GFCI vs AFCI: what each detects, shock versus fire protection, NEC requirements in homes, breaker and receptacle types, dual-function devices and why they trip.
GFCI (ground-fault circuit interrupter) and AFCI (arc-fault circuit interrupter) are two kinds of protective devices that guard against different hazards. A GFCI protects people from electric shock by detecting current leaking to ground. An AFCI protects buildings from fire by detecting dangerous arcing in wiring. Neither replaces the other, and many circuits need both.
Quick answer. GFCI = shock protection, required near water (bathrooms, kitchens, garages, outdoors, basements, laundry areas). AFCI = fire protection, required on most 120 V living-area circuits in homes (bedrooms, living rooms, kitchens, hallways and similar). A dual-function device provides both.
GFCI and AFCI compared
| GFCI | AFCI | |
|---|---|---|
| Protects against | Electric shock | Fire from arcing |
| Detects | Imbalance between hot and neutral current | Electrical signatures of arcing |
| Trips at | About 5 mA of leakage | Arc patterns, independent of load current |
| Typical locations | Wet and damp areas | Living areas and bedrooms |
| Forms | Receptacle, breaker, portable, cord | Breaker, outlet branch circuit (receptacle) |
How a GFCI works
In a healthy circuit, all the current that flows out on the hot conductor returns on the neutral. A GFCI continuously compares the two. If they differ by about 5 milliamperes, meaning some current is returning by another path such as through a person to ground, it opens the circuit within a fraction of a second.
That threshold is far below the current needed to trip an ordinary breaker, which responds to tens or hundreds of amperes. A circuit breaker protects the wire; a GFCI protects the person.
How an AFCI works
An arc is current jumping across a gap: a loose terminal screw, a cord crushed under furniture, a nail through a cable. Arcs can reach thousands of degrees and ignite insulation or wood framing while drawing no more current than a normal load, so a standard breaker never sees them.
An AFCI contains electronics that recognize the characteristic waveform of hazardous arcing and trip the circuit. Modern combination AFCIs detect both parallel arcs, between hot and neutral or ground, and series arcs, in a single damaged conductor.
Where GFCI protection is required
For dwellings, the National Electrical Code requires GFCI protection for 125 V to 250 V receptacles in locations including:
- Bathrooms
- Kitchens
- Garages and accessory buildings
- Outdoors
- Crawl spaces and unfinished basements
- Laundry areas
- Within 6 feet of the edge of a sink, bathtub or shower
- Boathouses and areas near pools and spas
The list has grown with each code edition, and the edition adopted locally governs.
Where AFCI protection is required
For dwellings, AFCI protection is required on 120 V, 15 A and 20 A branch circuits supplying outlets and devices in kitchens, family rooms, dining rooms, living rooms, parlors, libraries, dens, bedrooms, sunrooms, recreation rooms, closets, hallways, laundry areas and similar rooms. Requirements also apply when existing circuits in those areas are extended or modified.
GFCI breaker, GFCI receptacle or dual-function
| Option | Advantage | Consideration |
|---|---|---|
| GFCI receptacle | Reset at the point of use; protects downstream receptacles wired from its load terminals | One receptacle device per protected run |
| GFCI breaker | Protects the whole circuit including its wiring | Reset at the panel |
| AFCI breaker | Protects the whole circuit from the panel | Reset at the panel |
| Dual-function breaker | GFCI and AFCI in one device | Higher cost; one device serves both requirements |
| Dual-function receptacle | Both protections at the first outlet | Wiring from the panel to that outlet is not arc-protected |
A circuit serving a kitchen, for example, may need both GFCI and AFCI protection, which a single dual-function breaker provides.
Why they trip
GFCI trips usually point to moisture in an outdoor receptacle or cord connection, a damaged appliance cord, or an appliance with internal leakage. Long outdoor runs with many connections can also accumulate leakage.
AFCI trips may indicate a genuine arc, a loose connection, a shared neutral between circuits, or interference from some motors and older appliances. Persistent tripping should be investigated rather than worked around; replacing an AFCI with a standard breaker removes required protection. See why a breaker keeps tripping.
Testing
Both device types have a test button. Manufacturers recommend pressing it monthly. The device should trip; a GFCI receptacle is reset with its reset button and a breaker by switching it fully off and back on. A device that fails to trip should be replaced.
Frequently asked questions
What is the difference between GFCI and AFCI? A GFCI prevents electric shock by detecting current leaking to ground. An AFCI prevents fires by detecting arcing in wiring and connected cords.
Can one device do both? Yes. Dual-function breakers and receptacles combine GFCI and AFCI protection.
Is AFCI required in kitchens? In current code editions, yes, on 120 V, 15 A and 20 A circuits; kitchen receptacles also require GFCI protection, so both apply.
Does a GFCI protect against overloads? A GFCI receptacle does not; the breaker does. A GFCI breaker includes overcurrent protection as well.
Why does my GFCI trip when it rains? Water entering an outdoor receptacle, cover or extension cord connection creates a leakage path to ground. Weather-resistant covers rated "in use" and outdoor-rated cords reduce it.
Scope
This article describes requirements under the National Electrical Code in the United States. Required locations vary by code edition and local amendment. Installation of GFCI and AFCI breakers should be carried out by a licensed electrician.
Written by Chameera Sampath. Not yet reviewed by a licensed electrician — see the methodology page. To report an error, use the contact page.