AFCI wiring details showing the black  and white circuit and white breaker wire connectcions (C) Daniel Friedman at GFCI Installallation Options & Wiring
Ground Fault Circuit Interruptor Alternatives & Wiring Details

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Ground Fault Circuit Interrupters, GFCI Device Choices & Wiring Details

How to choose a GFCI device and how to install GFCI circuit breakers, receptacles, or portable, stand-alone GFCI protection devices.

This article series GFCI and AFCI protection for buildings.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

GFCI Options, Installation & Wiring Instructions

GFCI circuit breaker wiring, 120V adapted from Siemens, cited in this article (C) InspectApedia.comAs we introduce also if certain high-risk electrical circuits in your home or building is not already protected by GFCI devices in the electrical panel or at the appropriate electrical receptacles ("wall plugs"), we recommend that you have that protection added.

The high shock risk areas for which GFCIs add significant safety protection are damp or wet locations or locations where a person is likley to be handling an electrical device and be close to a sink, tub, shower or other plumbing or water equipment.

The GFCI detects a tiny (about 4 to 5 milliamps) flow of electrical current between the electrical circuit or something plugged-in to a GFCI-protected electrical receptacle) and the circuit "ground" or the earth. On detection of this current flow the GFCI quickly trips (in about a tenth of a second) to turn off the electrical circuit to reduce the chances of a dangerous or even fatal shock.

Typical GFCI-protected locations include bathrooms, garages, kitchens, at outdoor electrical circuits and of course near swimmng pools. That's not the whole list. At GFCI PROTECTION, GFCI CODES we provide a full list of the locations where electrical codes require this protection in new or renovation construction.

Watch out: never plug any life-saving devices into a GFCI electrical receptacle that will lose power during testing. Every receptacle that will lose power when a GFCI trips should be labelled GFCI-Protected.

We also caution against plugging a refrigerator or freezer or other critical cold-storage equipment into a GFCI-protected receptacle (for example downstream from the actual GFCI devicve) as any condition that trips the GFCI can leave the cold storage equipment off without notice.

Some electrical circuits that need to be assured of continuous operation include medical equipment, refrigerators, freezers, and sump pumps.

See also FREEZE-PROOF A BUILDING where we describe GFCI protection on heat tape circuits powering heat tapes for manufactured and mobile homes.

Similar issues regarding building water entry control are discussed at SUMP PUMP PROTECTION

Four Ways to Add GFCI Protection

  1. GFCI circuit breaker: Install a GFCI circuit breaker in the electrical panel, replacing the original breaker, to protect an entire circuit, such as a kitchen, garage, or outdoor receptacle circuit

GFCI circuit breakers in an electrical panel (C) Daniel Friedman at

Below is a Siemens 120V single pole ground fault circuit interruptor circuit breaker or GFCI breaker. The company provides a range of GFCI breakers including 1-pole and 2-poles, from 15A to 60A in size.

Siemens GFCI circuit breaker at

The company's data sheet for this GFCI breaker series notes that while a load neutral wire is not required on the circuit, the coiled white pigtail wire from the breaker must be connected to the neutral bus in the electrical panel for the GFCI to work.

GFCI circuit breaker wiring, 120V adapted from Siemens, cited in this article (C)

Other brands and models of GFCI circuit breakers require that

AFCI wiring details showing the black  and white circuit and white breaker wire connectcions (C) Daniel Friedman at

Watch out: before buying a GFCI circuit breaker be sure that the breaker is the proper one for the brand and model of electrical panel into which it is to be installed.

OK so what are the exact steps in wiring up or installing a GFCI device?

At CIRCUIT BREAKER REPLACEMENT we describe in further detail the steps followed to replace an existing circuit breaker with a GFCI-type (or AFCI-type) circuit breaker in an electrical panel.

GFCI Add-on Space Limitations in Some Electrical Panels

Standard circuit breaker widths, using Siemens as an example are 1" for a 120V breaker and 2" for a 240V breaker. In some electrical panels, such as our electrical panel photo shown just above on this page, you may find both full-width and half-width breakers already installed.

If the electrical panel is full or quite crowded you may find that you need to replace several normal-width circuit breakers with narrow half-width circuit breakers - a procedure called "skinnying-up" in the panel - in order to make room for a full-width GFCI breaker.

Watch out: if you have to change some circuit breakers from full to half-width or "skinny" circuit breakers AND if there are multi-wire shared-neutral circuits originating in the electrical panel, you will need to take care in locating those circuit breaker pairs to assure that each breaker is on a different panel bus connector and phase. Details are at MULTI-WIRE CIRCUITS

  1. GFCI wall receptacle: Install a GFCI electrical receptacle to replace an existing electrical receptacle in a high-risk location such as a bathroom or kitchen etc.

    The GFCI receptacle will protect any device plugged in to that receptacle and it will protect all of the electrical receptacles (and devices plugged into them) that are wired "downstream" from the receptacle where the GFCI is placed.

    In some buildings bathroom receptacles are wired in series between two or more baths and a GFCI is placed in the first receptacle in that string.

GFCI wall receptacle installed in a kitchen (C) Daniel Friedman at

  1. Portable GFCI devices: Use a plug-in or portable GFCI protection device that is connected to a wall receptacle.

    Often a portable GFCI device is simply a short extension cord that includes at one end its own GFCI protection. Devices that are then plugged into the GFCI-protection device are themselves protected, as are their users.

    We often use a portable GFCI protector in construction projects to run our power tools because we don't count on every building or home where we work to have properly-installed GFCI protection.

Yellow Jacket 2516 14/3 Portable GFCI Protected 4-outlet extension cord - sold at electrical suppliers and online such as by Amazon - here shown at

Shown above: a Yellowjacket-brand portable GFCI protected extension cord.

  1. GFCI-protected tools, devices, appliances: some devices may include their own built-in GFCI device. Shown below: Toughbuilt TB-S560 universal miter saw stand with its own built-in GFCI protection, sold at Home Depot stores and by other suppliers.

Toughbilt miter saw stand that includes its own GFCI protection - at

GFCI Installation Guides & Device Specifications


Continue reading at GFCI TEST PROCEDURES or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.

Or see BUILDING CODE DOWNLOADS - free downloadable PDF files of building codes & standards

Or see CIRCUIT BREAKER REPLACEMENT - how to replace a circuit breaker

Or see this

GFCI Article Series





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