Ground-fault circuit-interrupters, or GFCIs, are life-saving devices found on electrical receptacles (outlets), circuit breakers, extension cords, and other electrical equipment. They detect imbalances in the electrical current and quickly shut off the power to minimize the risk of shock. For example, if you're drying your hair in the bathroom and some water splashes into your hair dryer and creates a short circuit, the GFCI outlet will turn itself off—in a tiny fraction of a second.
GFCI protection is most commonly required in locations where electricity is likely to come into contact with water.
Different methods of GFCI protection have been available since 1971, and each revision of the National Electrical Code (NEC), which is revised every three years, has expanded the requirements. There are other protective measures built into a wiring system, but GFCI protection is the one that protects against shock and electrocution.
Where You Need GFCI Protection
The National Electrical Code, or NEC, has specific GFCI requirements for dwelling units. Article 210.8 states that ground-fault circuit-interrupters shall be used for all 125-volt, single-phase, 15- and 20-amp receptacles installed in the following locations:
- Bathrooms: All receptacles must be GFCI protected.
- Garages and accessory buildings: GFCI protection must be included on all receptacles in structures that have a floor located at or below grade level, not intended as habitable rooms and limited to storage areas, work areas, and areas of similar use.
- Outdoors: All outdoor receptacles must be GFCI-protected, with one exception: receptacles that are not readily accessible and are supplied by a dedicated branch circuit for electric snow-melting or deicing equipment do not need to be protected.
- Unfinished basements: Unfinished basements are defined as portions or areas of the basement not intended as habitable rooms and limited to storage areas, work areas, etc. Receptacles in these areas must have GFCI protection. Exceptions: GFCI protection is not required for the receptacles supplying only a permanently installed fire alarm or burglar alarm system, receptacles that are not readily accessible, or receptacles on a dedicated branch circuit and labeled for use with a plug-in equipment (ex: sump pump).
- Crawl spaces: In unfinished areas located at or below grade level, the same GFCI requirements are in effect as for basements.
- Kitchens: All receptacles serving countertop areas and any receptacle within 6 feet of a sink must have GFCI protection. Also, the receptacle supplying a dishwasher should be GFCI-protected.
- Laundry, utility, and wet bar sinks: Where receptacles are placed within 6 feet of the outside edge of the sink, they require GFCI protection.
- Pool/spa areas: GFCI protection is required for lights and lighting outlets; receptacles for pumps; all receptacles within 20 feet of a pool, spa, or fountain; and power supply for a pool cover.
Tips for Meeting GFCI Requirements
While the NEC is the leading authority on all things electrical, your local building authority has the final word on GFCI requirements (and everything else in your house). Check with your local building department for specific rules for installations in your area; in rare instances, local codes may differ from the requirements of the NEC.
Note that the requirement for GFCI protection doesn't mean that a GFCI receptacle is required at each location. GFCI protection can be provided by a GFCI circuit breaker that protects every device along the circuit.
Also, a single GFCI receptacle can be wired to protect other devices "downstream." This allows you to install one GFCI receptacle along the circuit that can protect others—provided this is allowed by your local code.
An additional method of wiring protection, AFCI (arc-fault circuit-interrupter), was mandated by the NEC with the 2017 edition of the Code for all 15-amp and 20-amp 120/125-volt circuits. The rules for AFCI protection are in addition to whatever GFCI requirements exist. As is the case with GFCIs, AFCI protection can be offered by either special circuit breakers or special outlet receptacles.
GFCIs operate by sensing imbalances in current flow, and are best suited for protecting against shock; AFCIs on the other hand, sense tiny sparks, or arcs, in the wiring, and serve to protect against fire.
Thus, both GFCI and AFCI protection may be required in many locations in your home.
Although the AFCI requirement applies mostly to new construction, the Code now requires that whenever you are replacing a receptacle in a location that now calls for AFCI protection, the new receptacle must include AFCI protection.
This means that whenever you install a GFCI in a 15-amp or 20-amp circuit, the receptacle will now need to include AFCI protection. This can be achieved by installing a special AFCI circuit breaker on the circuit in question, but these are expensive devices. A less expensive solution is to install a special combination AFCI/GFCI dual function receptacle that offers both forms of protection.
Although this may seem complicated, just keep these rules in mind:
- Where a circuit is already protected by an AFCI circuit breaker, you can install a standard GFCI receptacle wherever the Code requires GFCI protection.
- Where a circuit does not have an AFCI breaker, install a duel-function AFCI/GFCI receptacle where GFCI protection is needed.