This article was posted 02/20/2007 and is most likely outdated.

Article 210: Branch Circuits, Part Two: GFCIs and AFCIs
 

 
Topic - NEC
Subject
- Article 210: Branch Circuits, Part Two: GFCIs and AFCIs

February 20, 2007  

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Article 210: Branch Circuits, Part Two: GFCIs and AFCIs

By Mike Holt for EC&M Magazine

Apply GFCIs and AFCIs without tripping over the Code.

Article 210 provides GFCI requirements in 210.8 and AFCI requirements in 210.12. These requirements apply to 125V receptacles rated at 15A or 20A (circuits are 120V, but the receptacles are rated 125V). Any time we refer to a receptacle in this discussion of GFCIs or AFCIs, we are referring to this kind of receptacle only.

Article 210 frequently uses the word “outlet.” This isn’t limited to just receptacles. Article 100 defines an outlet as a point in the wiring system where current supplies a load. This definition includes receptacles. But it also includes outlets for lighting, paddle fans, and smoke alarms.

GFCI basics
Before we get into GFCI requirements, let’s address two basic points. First, GFCIs do work on two-wire circuits. A GFCI works by measuring the current on the ungrounded conductor and comparing it to the current on the grounded (neutral) conductor. If the difference between the two is greater than 4-6 miliamperes, the circuit is interrupted. With this in mind, you can see how the equipment grounding conductor does not play a pivotal role in the operation of the GFCI. <text2>It’s also worth noting that all Code-change proposals to lessen the protection in bathrooms have been rejected. In fact, GFCI coverage has been expanding (Sidebar 1), and will probably continue to expand in the future. The reason is simple: safety.

GFCIs in dwelling units
GFCI protection is required for receptacles installed in any of the following eight areas of a dwelling unit [210.8(A)]:

  • Bathroom
  • Garage
  • Outside
  • Crawl space (at or below grade)
  • Unfinished basement
  • Kitchen
  • Laundry
  • Boathouse

Bathroom. A bathroom must have at least one 15 or 20A, 125V receptacle. All bathroom receptacles must be GFCI-protected. At least one receptacle must be within 3 ft of the outside edge of each basin [210.52(D)].

This circuit can have no other outlets [210.11(C)(3). This means, for example, it can’t supply power to an outside receptacle or a garage receptacle. Exception: Where the 20A circuit supplies only a single bathroom, it can supply power to outlets for other equipment within the same bathroom, such as lighting outlets or an exhaust fan. In that case, follow the requirements of 210.23(A)(1) and (A)(2) for circuit loading.

Garage. A garage attached to a dwelling unit must have a receptacle [210.52(G)]. In an accessory building or a detached garage with power, a receptacle is also required. In either case, the receptacle must be GFCI protected [210.8(A)(2)]. A couple of exceptions exist:

1. Receptacles that aren’t readily accessible, such as those in the ceiling for the garage door opener motor. See the definition of “Readily Accessible” in Article 100.

2. A single receptacle on a dedicated branch circuit identified for a specific cord-and-plug connected appliance, such as a refrigerator or freezer. You can use a duplex receptacle without GFCI protection for two such appliances. Receptacles permitted by this exception must be within six feet of the appliance [210.50(C)].

Receptacles that aren’t readily accessible (or those for a dedicated branch circuit for a specific cord-and-plug connected appliance, as permitted in the two exceptions above) do not  count as the required receptacle described in 210.52(G).

Outside. Receptacles installed on the outside of a dwelling unit (even if installed under the eaves of roofs) must be GFCI protected.

Each ground floor unit of a multifamily dwelling (one that contains three or more dwelling units [Article 100]) with individual exterior entrances must have at least one outdoor receptacle with GFCI protection. Dwelling units above ground level of a multifamily dwelling unit do not require an outdoor receptacle. If you choose to install one, it still must be GFCI protected [210.52(E)].

GFCI protection isn’t required for a fixed electric snow-melting or deicing equipment receptacle supplied by a dedicated branch circuit, if the receptacle isn’t readily accessible and it complies with the requirements of 426.28 for Ground Fault Protection of Equipment (GFPE).

Crawl space. Receptacles installed in crawl spaces at or below grade of a dwelling unit must be GFCI protected. You don’t have to install a receptacle in the crawl space, except when heating, air-conditioning, and refrigeration equipment is installed there [210.63].

Basement. You must install a receptacle in each unfinished portion of a dwelling unit basement [210.52(G)]. If this space isn’t intended as a habitable room (and is limited to storage and work areas), provide GFCI protection for all receptacles (Figure210–19). Two exceptions exist:

1. Receptacles that aren’t readily accessible.

2. A receptacle on a dedicated branch circuit identified for a specific cord-and-plug connected appliance.

Kitchen. GFCI protection is required for all receptacles that serve countertop surfaces in a dwelling unit. It’s not required for receptacles that serve built-in appliances that do not serve the countertop such as dishwashers and kitchen waste disposals. See 210.52(C) for location requirements.

Laundry and Wet Bars. GFCI protection is required for receptacles located within 6 ft of a laundry, utility room, or wet bar sink [210.8(A)(7), 210.52(F)]. There are no exceptions to this rule, so even a receptacle for a clothes washer must be GFCI protected if it is within 6 ft of the sink (210–22).

Boathouse. You don’t have to install a receptacle in a boathouse. But if you do, it must be GFCI protected.

Commercial/industrial GFCI
Remember, we’re referring only to 125V receptacles rated at 15A or 20A [210.8(B)]. The requirements don’t apply to equipment rated 230V, such as a baseboard heater or room air conditioner. Nor do they apply to welding receptacles or other outlets that aren’t 125V and either 15A or 20A. GFCI protection is required for all receptacles installed in the following commercial/industrial locations.

Bathroom. You don’t have to install a receptacle in a commercial or industrial bathroom (as defined in Article 100). But if you do, it must be GFCI protected.

Kitchen. All receptacles installed in a kitchen must be GFCI protected, even those that do not serve the countertop. GFCI protection isn’t required for receptacles in employee break rooms containing portable cooking appliances. For this requirement, a “kitchen” is an area with a sink and permanent facilities for food preparation and cooking.

Rooftop. Receptacles installed on rooftops must be GFCI protected. A receptacle must be installed within 25 ft of heating, air-conditioning, and refrigeration equipment [210.63].
Just like the rule for outdoor dwelling unit receptacles, there is an exception for installations that fall under 426.28.

Outdoor public space. Receptacles installed outdoors in public spaces used by (or accessible to) the public must be GFCI protected. Whether the public has access is a judgment call, so check with the AHJ.

Heating, air-conditioning, and refrigeration equipment. All outdoor receptacles installed at an accessible location for the servicing of heating, air-conditioning, and refrigeration equipment per 210.63 must be GFCI protected.

Arc-Fault Circuit-Interrupters (AFCI)
An AFCI device de-energizes the circuit when it detects the current waveform characteristics that are unique to an arcing fault [210.12(A) (Figure210–36). It does not protect a person from shock. That’s what a GFCI does. AFCIs prevent fires from arc faults.

You cannot use an AFCI device to satisfy GFCI requirements (or vice versa). GFCI and AFCI are based on entirely different principles, though you can get both functions in one combination AFCI/GFCI device.

After January 1, 2008 (basically a 2008 NEC requirement), AFCI protection must be provided by a combination AFCI device (see Sidebar 2), as opposed to the branch/feeder type that is in use today.

Bedroom circuits. A 120V branch circuit that supplies outlets in dwelling unit bedrooms must be protected by a listed AFCI device (Figure 210-37).

Smoke alarms. These have to be AFCI protected if on a 15A or 20A bedroom circuit in a dwelling unit. This may seem to conflict with Article 760, but it doesn’t. The exemption from AFCI protection for the fire alarm circuit [760.21 and 760.41] doesn’t apply to the smoke alarm circuit. Why? Because a smoke alarm circuit isn’t a fire alarm circuit. It’s an alarm circuit [See NFPA 72, National Fire Alarm Code].

The GFCI requirements apply to receptacle outlets. The AFCI requirements apply to all outlets—where electricity is being “let out” so people can use it, if those outlets are 125V and either 15A or 20A.

GFCIs apply to dwellings and to commercial and industrial applications. They keep people from being shocked. AFCIs, for the time being, apply only to dwelling units. They keep wires from causing a fire where people are sleeping in their homes. Knowing you’ve properly applied GFCI and AFCI requirements to your branch circuits should help you sleep easier, too.

Sidebar 1. GFCI expanded coverage
Since 1971, the NEC has expanded GFCI protection requirements to include:

  • Aircraft Hangars, 513.12
  • Agricultural Buildings, 547.5(G)
  • Carnivals, Circuses, and Fairs, 525.23
  • Commercial Garages, 511.12
  • Cord and plug connected vending machines, 422.51
  • Elevator Pits, 620.85
  • Health Care Facilities, 517.20(A)
  • Mobile homes, 550.13(B)
  • Natural and artificially made bodies of water, Article 682
  • Portable or Mobile Signs, 600.10(C)(2)
  • Sensitive electronic equipment, 647.7
  • Swimming Pools,  Article 680
  • Temporary Installations, 590.6

Sidebar 2. Why combination devices?
Standard branch/feeder AFCI devices operate when the arc exceeds 75A peak. But combination AFCI protection devices detect arcs as low as 5A peak. This dramatic difference in detection enhances safety performance. Combination devices are also intended to protect the premises wiring as well as the cord connecting the appliance. These devices also “see” arc faults for both series arcs and parallel arcs, whereas branch/feeder type AFCIs only respond to parallel arcs. See UL 1699, Standard for Arc-Fault Circuit Interrupters (www.UL.com) for information on differences between the two types.

 

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Comments
  • great newsletter...beautiful way to sum it up! Please keep up the great work!!

    bill d
    Reply to this comment

  • do closets with lights have to be AFCI protected

    kevin
    Reply to this comment

  • In a recent email you said, "Laundry and Wet Bars. GFCI protection is required for receptacles located within 6 ft of a laundry, utility room, or wet bar sink [210.8(A)(7), 210.52(F)]. There are no exceptions to this rule, so even a receptacle for a clothes washer must be GFCI protected if it is within 6 ft of the sink (210–22)." I don't find 210-22 in the NEC either as an article or illustration. Can you clairfy?

    Thanks,

    Aaron

    Aaron Miller
    Reply to this comment

  • If you are upgrading old wiring and replace an outlet near a sink or where GFCI is now required,

    1. When do you need to upgrade to GFCI and when not (in general, if no local ordinances apply)?

    2. When will you need to bring in that 3rd ground wire anyway?

    I recently passed on a house that had its main fuse box nestled in between the studs right behind the kitchen sink, with a piece of loose paneling covering it since the door had been removed because it would obviously hit the faucet if left on. GFCI won't help you there...

    Matt
    Reply to this comment

  • one more place where the receptacle outlet is required to be a GFCI type, is in the Elevator Machine Room.

    alberto miranda
    Reply to this comment

  • Even though a GFI will work without an Equipment Grounding Conductor (better called an "Equipment Fault Conductor" or "Fault Wire"), couldn't this conductor still play a very important role in operating the GFI before someone actually uses the electrical equipment already plugged into the GFI ? Under this condition, wouldn't this Equipment Grounding Conductor provide a path for a low current fault (either ungrounded conductor arcing to the metal case allowing only a small amount of current or the grounded neutral conductor touching the metal case ? Therefore, this allows the unbalanced current in the GFI to open the circuit. Without the Equipment Grounding Conductor, the equipment operator may end up providing the path for the 4 to 6 ma leakage current. My point is ....shouldn't there be some emphasis that the Equipment Grounding Conductor does in fact play a vital role in the operation of the GFI in many situations before a person has to suffer any kind of shock even if it is only 4 to 6 ma for a moment. Mike, I believe you already know and understand the concept behind what I am saying. I just wanted to add an emphasize here that the Equipment Ground is also useful for low current faults.

    Ralph Greene
    Reply to this comment

  • I just want to say thank you for all the information you have shared with me. I really do appreciate all the help you have given me. Thanks again, T. Quesada

    Tommy Quesada
    Reply to this comment

  • I looked into arc fault when it first came out. There seems to be a lot of conflict with it. Basically it doesn't do what it was intended to do. Who am I to say but it sounds a lot like a money game to me. Are these devices helping anyone, any record of this, eveidence that hey this AFCI breaker saved my life. Maybe so, but I haven't heard.

    Andy in Nashua

    Andy
    Reply to this comment

  • I believe the bathroom requires a 20amp receptacle not a 15 or 20 amp. See section 210.11 (C) (3). This is due mainly to the loads reqired for most hair dryers today. Please correct me if wrong. Thank you. Danny

    Dan B.
    Reply to this comment

  • Great newsletter for the review of GFCI and Arc-fault uses.

    Ed Gouldsmith
    Reply to this comment

  • Just so I am clear on this. There are GFCI's,AFCI's,COMBINATION GFCI/AFCI's,Standard Branch Feeder AFCI's and Combination AFCI's? Thanks,

    Mark Prairie
    Reply to this comment

  • Thank-you for the news letters. A problem with the AFCI requirements in my jurisdiction is the homes are not typically wired to minimum code. It used to be common to have each bedroom on a seperate branch circuit and often the lighting was seperate too. Now, I see 1 maybe 2 branch circuits in a 4 bedroom home. Frankly, I feel this has been a step backward and the wiring is barely adequate. Maybe this would have happened with the higher costs of all electrical materials too.

    John Phillips
    Reply to this comment


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