Article 210 Branch Circuits

I. General Provisions

Article 210 applies to all branch circuits except motor loads. When a branch circuit supplies this type of load in combination with a motor load, both this article and Article 430 must be followed. When the branch circuit supplies only motor loads, Article 430 must be followed.

The rules for branch circuits in Table 210.2 amend or supplement this article as noted.

Branch circuits are rated according to the maximum permitted rating or setting of their overcurrent device. Generally, they are classified as 15, 20, 30, 40, and 50 A. There is an exception.

Multiwire branch circuits are permitted. They can only supply line to neutral load, except if it supplies one piece of equipment or if all ungrounded conductors of the circuit are opened by the overcurrent device simultaneously.

In general, the grounded conductor must be identified in accordance with Section 200.6. The equipment grounding conductor must be identified in accordance with Section 250.119. If there are branch circuits being supplied at different voltage systems in premises, then all ungrounded conductors must be identified as to which voltage system they are on. The method of identification can be color coding, tagging, marking tape, or any other approved means. The identification must be posted permanently at the branch circuit distribution equipment.

(A) The voltage between conductors cannot be greater than 120 V for lighting fixtures and cord-and-plug connected loads of less than 1440 VA or less than ¼ hp in dwelling units, hotel and motel guest rooms, guest suites, and the like.

(B) Circuits not exceeding 120 V to ground can supply auxiliary equipment of electric discharge lamps, utilization equipment, and terminals of lampholders within their voltage rating.

(C) Circuits between 120 and 277 V to ground can supply mogul-base screw-shell lampholders, lampholders used within their voltage rating, auxiliary equipment to electric discharge lamps, listed electric discharge fixtures, and utilization equipment. Additionally, these circuits can supply listed lamp-holders that are supplied at 120 V or less from a stepdown auto-transformer which is part of the fixture and the outer shell terminal is connected to the grounded conductor of the branch circuit.

(D) 600 V between conductors.

(E) Over 600 Volts between conductors.

(A) Receptacle Outlet Location. The location of receptacle outlets in branch circuits must be as noted in Part III of Article 210.

(B) Multiple Branch Circuits. If more than one device or equipment on the same yoke is supplied by more than one branch circuit then a means must be provided at the panelboard where the branch circuits originate to simultaneously disconnect the ungrounded conductors supplying those receptacles.

(A) Dwelling Units. All 125-V single-phase 15- and 20-A receptacles must have ground fault protection for personnel when installed in bathrooms, garages and at or below grade level parts of storage or work areas and similar use in accessory buildings (two exceptions), outdoors (one exception), crawl spaces at or below grade level, unfinished basements (two exceptions), kitchens where the receptacles are serving counter tops, and laundry, utility, and wet bar sinks where the receptacle is within 1.8 m (6 ft.) of the outside edge of the sink and to serve the counter top. There are exceptions.

(B) Other than Dwelling Units. Ground-fault circuit interrupter receptacles are required in bathrooms, commercial and institutional kitchens, on rooftops, and outdoors in public spaces and outdoors where complying with 210.63 on all 125-V single-phase 15- and 20-A outlets. There is an exception.

(C) Boat Hoists. Ground-fault protection for personnel must be installed where power is provided for boat hoists in dwelling units that are supplied by 125-volt, 15- and 20-ampere branch circuits.

Branch circuits have to be provided to supply the loads in accordance with Section 220.10. Also they are to be provided where required elsewhere in the Code, for dwelling units as specified in (C), and where not covered in Section 220.10.

(A) Number of Branch Circuits. The minimum number of branch circuits is determined by the total calculated load and the rating or size of the circuits that are used. They have to supply the load and in no case can the load exceed the maximum specified in Section 220.18.

(B) Load Evenly Proportioned among Branch Circuits. When the load is computed on a volt-ampere per square foot or square meter basis the wiring system up to and including the branch circuits panelboards has to be rated to carry the load. The load has to be evenly proportioned among the branch circuits. You only have to install the branch circuits and overcurrent devices for the connected load.

(C) Dwelling Units. Two or more 20 ampere small appliance branch circuits for outlets required by Section 210.52(b) are to be installed. At least one 20-ampere branch as required by 210.52(F) is to be installed for laundry receptacles and at least one 20-ampere branch circuit is to be installed for bathroom receptacles. No other outlets are permitted on these laundry and bathroom circuits. These are in addition to other requirements. There is an exception for the bathroom.

An arc fault circuit interrupter is a device which will offer protection from an arcing fault. This device is required in all branch circuits that supply 125-volt, single-phase, 15- and 20-ampere receptacles in dwelling unit bedrooms. It must provide protection for the entire branch circuit. Branch/Feeder AFCI can be used for 210.12(B) until January 1, 2008. The AFCI can be located in a location other than the origination of the circuit if in compliance with the two exceptions.

II. Branch-Circuit Ratings

(A) Branch Circuits No More Than 600 Volts.

(1) General. Generally, conductors must have a capacity not less than the maximum load. If a branch circuit supplies either continuous or continuous and noncontinuous loads, the ampere rating of the circuit must be at least equal to or greater than the noncontinuous load plus 125% of the continuous load. Various tables are supplied. A fine print note states that if the conductors are sized so that the maximum voltage drop on the branch circuit to the outlet is not greater than 3% of the total voltage drop, and for both feeder and branch circuit is not greater than 5%, a reasonable efficiency of operation will be provided.

(2) Multioutlet Branch Circuits. Conductors for receptacles for multioutlet branch circuits must be rated at least that of the branch circuit.

(3) Household Ranges and Cooking Appliances. Ratings cannot be less than the rating of the load. In cases of ranges of 8¾ kW or more, the minimum circuit rating is 40 A. Neutrals and conductors are permitted to be smaller in accordance with the Code. There are two exceptions.

(4) Other Loads. Except for cooking appliances and loads noted in Section 210.2, ratings must be sufficient for the loads supplied, but in no case can a conductor be smaller than 14 AWG. Exceptions are made for tap conductors and fixture wires and cords.

(B) Branch-Circuits Over 600 Volts. The ampacity of the conductors must be sized in accordance with Sections 310.15 and 310.60. Branch-circuit conductors over 600 volts have to be sized as follows:

(1) General. The ampacity of the conductors cannot be less than 125% of the load of equipment that will be used simultaneously. The designed potential load is to be used.

(2) Supervised Installations. A supervised installation is defined in the Code as the portions of a facility where two conditions are met. The first states that the conditions of the design are made under engineering supervision. The second states that the maintenance, monitoring, and servicing of the system is to be done with qualified personnel with documented training and experience in over 600 volt systems. Qualified personnel under engineering supervision can do branch-cricuit conductor sizing.

(A) Continuous and Noncontinuous Loads. If the circuit has continuous or a combination of continuous and noncontinuous loads then the rating of the overcurrent device has to be the sum of the noncontinuous and 125% of the continuous loads. There is an exception for devices listed for operation at 100% of rating.

(B) Conductor Properties. Conductors must be protected in accordance with Section 240.4.

(C) Equipment. Refer to applicable articles in Section 240.3.

(D) Outlet Devices. Do not exceed ratings or settings in Section 210.21.

Outlet devices must be rated at least that of the load.

(A) Lampholders connected to a branch circuit rated at more than 20 A must be a heavy-duty type.

(B) Receptacles. A single receptacle on an individual branch circuit can have a rating only equal to or larger than the rating of the individual branch circuit it is on except when installed in accordance with Section 430.81(C). The maximum load from a cord and plug connection where there is more than one receptacle on the circuit is shown in Table 210.21(B)(2). The ratings of receptacles where there is more than one on a circuit are shown in Table 210.21(B)(3). If the branch circuit rating is more than 50 A, then the receptacle rating must be at least as large as the branch circuit. The ampere rating of a range receptacle can be based on a single range as noted in Table 220.19. There are some exceptions to the text and tables.

The load cannot exceed the branch circuit rating. Branch circuits that supply more than one receptacle or outlet follow the rules in (A) through (D) below and summarized in Section 210.24 and Table 210.24.

[1] These gauges are for copper conductors.

[2] For receptacle rating of cord-connected electric-discharge lighting fixtures, see Section 410.30(C).

(A) 15 and 20 Ampere Branch Circuits. 15- and 20-A branch circuits can supply lighting loads, utilization equipment, or a combination. The rating of one cord- and plug-connected utilization equipment not fastened in place cannot be more than 80% of the branch-circuit ratings. Connected utilization equipment cannot be more than 50% of the branch-circuit rating where both connected and cord-and-plug loads are used.

(B) 30 Ampere Branch Circuit. A 30-A branch circuit can supply heavy-duty lampholders in fixed lighting units in all occupancies except dwelling units. They can also supply utilization equipment in all occupancies. One cord- and plug-connected utilization equipment cannot be more than 80% of the branch circuit rating.

(C) 40 and 50 Ampere Branch Circuits. A 40- and 50-A branch circuits supply the same lighting loads as the 30-A branch circuit, connected cooking appliances in any occupancy, and infrared heating units in occupancies dwelling units. They can supply fastened-in-place cooking appliances in dwelling units.

(D) Branch Circuits Larger Than 50 Amperes. If the branch circuit is larger than 50 A, it can only supply nonlighting loads.

Table 210.24 provides a summary of branch-circuit requirements for circuits that contain two or more outlets or receptacles other than those required in Section 220.11(C)(1) and (2). Refer to 210.19, 210.20 and 210.21 for specifics to branch circuits.

Dwelling unit branch circuits can only supply circuits in or associated with that dwelling unit in multifamily dwellings. Branch circuits supplying loads such as lighting, alarms, and signals for common areas cannot be supplied from a dwelling unit panelboard.

III. Required Outlets

A cord connection is considered a receptacle outlet if it is supported by a permanently installed cord pendant. When it is known that a flexible cord will be used, a receptacle outlet should be installed. Appliance outlets for specific equipment are to be installed within 1.8 m (6 ft.) of the location of the appliance.

Requirements for 125 volt, 15 and 20 ampere receptacles are provided in this section.

(A) General Provisions. Receptacle outlets must be installed in dwelling units so that a receptacle outlet is not more than 1.8 m (6 ft.) from any point in a wall space along the floor line. This applies to wall spaces 600 mm (2 ft.) wide or larger, those containing fixed panels in exterior walls, and those containing fixed room dividers (i.e., railings or free standing bar-type counters). Sliding panels in exterior walls are excluded. A wall space is an unbroken wall along the floor (unbroken by doors, fireplaces, etc.). Each wall space 600 mm (2 ft.) wide or more is considered separately. Receptacles are to be spaced equally. Receptacles in floors and in lighting fixtures or appliances within cabinets or 1.7 m (5½ ft.) above the floor are not counted. The areas that this applies to are kitchen, family room, dining room, living room, parlor, library, den, sunroom, bedroom, recreation room, and similar types of rooms.

(B) Small Appliances. The required [Section 210.11(C) (1)] two or more 20-A small appliance branch circuits must serve all wall and floor receptacles covered by Section 210.52(A) and all counter top receptacles covered by Section 210.52(C) in areas such as dining room, breakfast room, pantry, and kitchen, including refrigeration equipment. Exceptions are made for switched receptacles supplied from a general purpose branch circuit as described in Section 210.70(A), Exception 1 and refrigeration equipment can be supplied from a 15-A or greater individual branch circuit. No other outlets are allowed on the required two or more 20-A small appliance branch circuits except clocks and power for supplemental equipment on gas fired ranges, ovens, or counter-mounted cooking equipment. The receptacles in kitchens serving countertops must be supplied by at least two small appliance branch circuits. These small appliance branch circuits or additional small appliance branch circuits can supply outlets in the kitchen or other rooms as specified in Section 210.52(B)(1). No small appliance branch circuit can supply more than one kitchen.

(C) Countertops. A receptacle is to be installed in each wall countertop space wider than 300 mm (12 in.) in kitchens and dining areas. No point along the wall can be farther than 600 mm (24 in.) from a receptacle measured horizontally. Receptacles are not required on a wall directly behind a rangetop or sink. If an island or peninsular countertop is 600 mm (24 in.) or more in one dimension and 300 mm (12 in.) or more in the other dimension it must have at least one receptacle. If a counter top is separated by a range, sink, or refrigerator each part is to be considered a separate counter top. Receptacles must be located above the counter top. No receptacle is to be more than 500 nm (20 in.) above the counter top. A receptacle which is covered by a fixed appliance or one in a dedicated space is not to be counted as a required outlet. There is an exception for the handicapped and a special island and peninsula condition.

(D) Bathrooms. A minimum of one wall receptacle is to be installed within 900 mm (3 ft.) of each basin on a wall or partition adjacent to the basin or counter top. It can be installed on the face of the basin cabinet not more than 12 in. below the counter top.

(E) Outdoor Outlets. At least one receptacle accessible at grade level must be installed in the front and rear of each one-family dwelling unit and each unit of a two-family dwelling unit that is at grade level. The receptacles cannot be higher than 6½ ft. above grade. At least one receptacle accessible from grade must be installed for each unit of a multifamily dwelling that is located at grade level and has an individual exterior entrance. These receptacles cannot be higher than 6½ ft. above grade. See 210.8(A)(3).

(F) Laundry Areas. A minimum of one outlet is to be installed in the laundry area. This is not required in multifamily dwelling units where laundry rooms are provided or laundry facilities are not individually installed.

(G) Basements and Garages. A minimum of one receptacle in addition to the one for the laundry is to be installed in the basement and garage with electricity of a one-family dwelling. Refer to Sections 210.8(A)(2) and (A)(5). If a portion of the basement is made a habitable room or rooms each unfinished portion must have a receptacle.

(H) Hallways. One receptacle must be installed in a hallway 3 m (10 ft.) or longer. The length of the hallway is measured along the centerline of the hall without going through a doorway.

Guest rooms or guest suites in a hotel or motel must comply with Sections 210.52(A) and (D) unless otherwise required for permanently installed furniture. If guest rooms or guest suites have permanent provisions for cooking they must comply with Section 210.52. There are requirements for permanent furniture layout and receptacle layout.

A minimum of one receptacle is required for each 3.7 linear m (12 ft) or major fraction of a show window. It is to be measured at the maximum width and the receptacle to be installed above the window.

(A) Dwelling Units. Every habitable room, as well as attached garages, detached garages with electric power, hallways, stairways, and bathrooms, must have a minimum of one lighting outlet controlled by a wall switch. This is also required for illumination on the exterior of outdoor exits or entrances on grade level. A receptacle is acceptable in place of the lighting outlet in habitable rooms other than kitchens and bathrooms. Remote automatic or central control can be used in hallways, outdoor entrances, and stairways. When an attic, utility room, underfloor space, or basement is used for storage or equipment requiring service, it must have a minimum of one lighting outlet controlled at the point of entry. There are requirements for stair lighting. The lighting outlets can be controlled by an occupancy sensor if it is in addition to a wall switch or is at the location of the wall switch with a manual override.

(B) Guest Rooms or Guest Suites. Guest rooms or guest suites in hotels, motels, and similar installations must have a minimum of one lighting outlet or receptacle connected to a wall switch. There are two exceptions.

(C) Other Than Dwelling Units. Requirements for lighting in attics or underfloor spaces for heating, air-conditioning, refrigeration equipment, or other equipment needing servicing are noted here.