6.3 GFCI Protection — Article 210.8

What a GFCI Actually Does

A ground-fault circuit interrupter compares the current leaving on the ungrounded conductor with the current returning on the grounded conductor. In a healthy circuit they are equal. If some current is returning by another path — through a person, through water, through a damaged raceway — the difference appears as an imbalance, and the device opens the circuit.

A Class A GFCI is defined by UL 943 to trip when the ground-fault current is 6 milliamperes or higher and not to trip when the ground-fault current is less than 4 milliamperes. That range is set below the level at which a typical adult loses the ability to let go of an energized object.

Distinguish this from ground-fault protection of equipment (GFPE), which operates at much higher levels — commonly 30 milliamperes for heating equipment, and up to 1200 amperes for the service GFPE required by 230.95. GFPE protects equipment and property, not people.

Dwelling Units — 210.8(A)

All 125-volt through 250-volt receptacles supplied by single-phase branch circuits rated 150 volts or less to ground installed in the following locations shall have GFCI protection for personnel:

The basement change in the 2020 edition is significant: earlier editions limited the requirement to unfinished portions of basements. In the 2020 NEC, all basement receptacles in the listed voltage range require GFCI protection.

The expansion from 125-volt to 125-volt through 250-volt is the other major 2020 change. A 240 V receptacle for a dryer or a garage compressor in a listed location now requires GFCI protection.

Other Than Dwelling Units — 210.8(B)

All single-phase receptacles rated 150 volts to ground or less, 50 amperes or less, and three-phase receptacles rated 150 volts to ground or less, 100 amperes or less, installed in the following locations shall have GFCI protection:

1. Bathrooms
2. Kitchens — 2020 broadened this beyond commercial kitchens to any area with a sink and permanent facilities for food preparation and cooking
3. Rooftops
4. Outdoors
5. Sinks — where receptacles are installed within 6 feet of the top inside edge of the bowl of the sink
6. Indoor damp or wet locations
7. Locker rooms with associated showering facilities
8. Garages, service bays, and similar areas other than vehicle exhibition halls and showrooms
9. Crawl spaces at or below grade level
10. Unfinished portions or areas of the basement not intended as habitable rooms
11. Laundry areas

The ampere thresholds are the point to memorize: 50 A single-phase, 100 A three-phase.

Boat Hoists, Appliances and Crawl Space Lighting

210.8(C) Boat Hoists. GFCI protection shall be provided for outlets not exceeding 240 volts that supply boat hoists installed in dwelling unit locations.

210.8(D) Specific Appliances. GFCI protection shall be provided for the outlets that supply the following appliances rated 150 volts or less to ground and 60 amperes or less, single- or three-phase: automotive vacuum machines, drinking water coolers and bottle fill stations, high-pressure spray washing machines, tire inflation machines, vending machines, sump pumps, dishwashers, and electric ranges, wall-mounted ovens, and counter-mounted cooking units where the receptacle or outlet is in a listed location.

The dishwasher entry is a notable 2020 addition — a hardwired dishwasher outlet in a dwelling now requires GFCI protection.

210.8(E) Equipment Requiring Servicing. GFCI protection shall be provided for the receptacles required by 210.63 — the HVAC servicing receptacle.

210.8(F) Outdoor Outlets. All outdoor outlets for dwellings, other than those covered in 210.8(A)(3), that are supplied by single-phase branch circuits rated 150 volts or less to ground, 50 amperes or less, shall have ground-fault circuit-interrupter protection for personnel. Note that this says outlets, not receptacles — a hardwired outdoor heat pump or mini-split outlet falls under it. An exception in the 2020 text addresses lighting outlets other than those covered in 210.8(C).

Reading the Rule Precisely

Several traps recur:

1. Outlet versus receptacle. 210.8(A) and (B) apply to receptacles. 210.8(D), (E) and (F) apply to outlets, which includes hardwired equipment.
2. Measured from where. The sink rule measures 6 feet from the top inside edge of the bowl — not from the faucet, cabinet edge, or countertop edge.
3. Voltage to ground. A 240 V two-pole circuit from a 120/240 V system is 120 V to ground, so it is within the 150-volt-to-ground scope.
4. The location determines the requirement, not the load. A receptacle in a garage supplying a freezer needs GFCI protection; the 2020 edition removed the old dedicated-equipment exceptions for garages and basements.

Where Protection May Be Provided

GFCI protection may be provided by a GFCI receptacle, a GFCI circuit breaker, or a listed GFCI deadfront device feeding downstream outlets. 210.8 requires the protection to be readily accessible in the general text of the section for many applications — check the specific subsection language.

406.4(D)(2) requires that where a receptacle is replaced at a location now required to have GFCI protection by 210.8, the replacement receptacle shall be GFCI protected. This applies even in an existing installation wired under an earlier Code.

Nuisance Tripping and Long Runs

GFCI devices respond to leakage, and every conductor has some. Very long runs, wet raceways, and motor loads with capacitive filters all contribute. In cold climates, a heat-trace circuit is a classic source: moisture ingress in a damaged cable produces steady leakage that eventually reaches the trip threshold.

The Code's answer for deicing and snow-melting equipment is not to remove protection but to use the right kind: 426.28 requires ground-fault protection of equipment for fixed outdoor electric deicing and snow-melting equipment, and 427.22 does the same for fixed electric heating equipment for pipelines and vessels. Those are GFPE devices at a higher trip level, not Class A GFCIs. The receptacle exception in 210.8(A)(3) for snow-melting and deicing equipment on a dedicated branch circuit per 426.28 exists for exactly this reason.

Do not respond to nuisance tripping by removing required GFCI protection. Investigate the leakage, verify the equipment grounding conductor is intact, check for moisture in boxes and raceways, and separate long runs onto their own devices.