BRANCH CIRCUITS

A. General Provisions 210-1. Scope. This article covers branch circuits except for branch circuits that supply only motor loads, which are covered in Article 430. Provisions of this article and Article 430 apply to branch circuits with combination loads. Exception: Branch circuits for electrolytic cells as covered in Section 668-3(c), Exception Nos. 1 and 4. 210-2. Other Articles for Specific-Purpose Branch Circuits. Branch circuits shall comply with this article and also with the applicable provisions of other articles of this Code. The provisions for branch circuits supplying equipment in the following list amend or supplement the provisions in this article and shall apply to branch circuits referred to therein: Article Section Air-Conditioning and Refrigerating Equipment 440-6 440-31 440-32 Busways 364-9 Circuits and Equipment Operating at Less than 50 Volts 720 Central Heating Equipment Other than Fixed Electric Space Heating Equipment 422-7 Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits 725 Closed-Loop and Programmed Power Distribution 780 Cranes and Hoists 610-42 Electronic Computer/Data Processing Equipment 645-5 Electric Signs and Outline Lighting 600-6 Electric Welders 630 Elevators, Dumbwaiters, Escalators, Moving Walks, Wheelchair Lifts, and Stairway Chair Lifts 620-61 ARTICLE 210 - BRANCH CIRCUITS 70-35 Article Section Fire Protective Signaling Systems 760 Fixed Electric Space Heating Equipment 424-3 Fixed Outdoor Electric Deicing and Snow-Melting Equipment 426-4 Infrared Lamp Industrial Heating Equipment 422-15 424-3 Induction and Dielectric Heating Equipment 665 Marinas and Boatyards 555-4 Mobile Homes and Mobile Home Parks 550 Motion Picture and Television Studios and Similar Locations 530 Motors, Motor Circuits, and Controllers 430 Pipe Organs 650-6 Recreational Vehicles and Recreational Vehicle Parks 551 Sound-Recording and Similar Equipment 640-6 Switchboards and Panelboards 384-32 Theaters, Audience Areas of Motion Picture and Television Studios, and Similar Locations 520-41 520-52 520-62 X-Ray Equipment 660-2 517-73 210-3. Rating. Branch circuits recognized by this article shall be rated in accordance with the maximum permitted ampere rating or setting of the overcurrent device. The rating for other than individual branch circuits shall be: 15, 20, 30, 40, and 50 amperes. Where conductors of higher ampacity are used for any reason, the ampere rating or setting of the specified overcurrent device shall determine the circuit rating. Exception: Multioutlet branch circuits greater than 50 amperes shall be permitted to supply nonlighting outlet loads on industrial premises where maintenance and supervision indicate that qualified persons will service equipment. 210-4. Multiwire Branch Circuits. (a) General. Branch circuits recognized by this article shall be permitted as multiwire circuits. A multiwire branch circuit shall be permitted to be considered as multiple circuits. All conductors shall originate from the same panelboard. (FPN): A 3-phase, 4-wire power system used to supply power to computer systems or other similar electronic loads may necessitate that the power system design allow for the possibility of high harmonic neutral currents. (b) Dwelling Units. In dwelling units, a multiwire branch circuit supplying more than one device or equipment on the same yoke shall be provided with a means to disconnect simultaneously all ungrounded conductors at the panelboard where the branch circuit originated. (c) Line to Neutral Load. Multiwire branch circuits shall supply only line to neutral load. 70-36 NATIONAL ELECTRICAL CODE Exception No. 1: A multiwire branch circuit that supplies only one utilization equipment. Exception No. 2: Where all ungrounded conductors of the multiwire branch circuit are opened simultaneously by the branch-circuit overcurrent device. (FPN): See Section 300-13(b) for continuity of grounded conductor on multiwire circuits. (d) Identification of Ungrounded Conductors. Where more than one nominal voltage system exists in a building, each ungrounded system conductor shall be identified by phase and system. The means of identification shall be permanently posted at each branchcircuit panelboard. (FPN): The means of identification of each system phase conductor, wherever accessible, may be by separate color coding, marking tape, tagging, or other equally effective means. See Sections 215-8, 230-56, and 384-3(e) for high leg marking. 210-5. Color Code for Branch Circuits. (a) Grounded Conductor. The grounded conductor of a branch circuit shall be identified by a continuous white or natural gray color. Where conductors of different systems are installed in the same raceway, box, auxiliary gutter, or other types of enclosures, one system grounded conductor, if required, shall have an outer covering of white or natural gray. Each other system grounded conductor, if required, shall have an outer covering of white with an identifiable colored stripe (not green) running along the insulation or other and different means of identification. Exception No. 1: The grounded conductors of mineral-insulated, metalsheathed cable shall be identified by distinctive marking at the terminals during the process of installation. Exception No. 2: As permitted in Exception No. 3 of Section 200-6(a) and the Exception to Section 200-6(b). (b) Equipment Grounding Conductor. The equipment grounding conductor of a branch circuit shall be identified by a continuous green color or a continuous green color with one or more yellow stripes unless it is bare. Exception No. 1: As permitted in Section 250-57(b), Exception Nos. 1 and 4 and Section 310-12(b), Exception Nos. 1 and 2. Exception No. 2: The use of conductor insulation having a continuous green color or a continuous green color with one or more yellow stripes shall be permitted for internal wiring of equipment if such wiring does not serve as the lead wires for connection to branch-circuit conductors. 210-6. Branch Circuit Voltage Limitations. (a) Occupancy Limitation. In dwelling units and guest rooms of hotels, motels, and similar occupancies, the voltage shall not exceed 120 volts, nominal, between conductors that supply the terminals of: (1) Lighting fixtures. ARTICLE 210 - BRANCH CIRCUITS 70-37 (2) Cord- and plug-connected loads 1440 volt-amperes, nominal, or less, or less than ¼ horsepower. (b) 120 Volts Between Conductors. Circuits not exceeding 120 volts, nominal, between conductors shall be permitted to supply: (1) The terminals of medium-base screw-shell lampholders or lampholders of other types applied within their voltage ratings. (2) Auxiliary equipment of electric-discharge lamps. (3) Cord- and plug-connected or permanently connected utilization equipment. (c) 277 Volts to Ground. Circuits exceeding 120 volts, nominal, between conductors and not exceeding 277 volts, nominal, to ground shall be permitted to supply: (1) Listed electric-discharge lighting fixtures equipped with mediumbase screw-shell lampholder. (2) Listed incandescent lighting fixtures equipped with medium-base screw-shell lampholder, where supplied at 120 volts or less from the output of a stepdown autotransformer that is an integral component of the fixture, and the outer screw-shell terminal is electrically connected to a grounded conductor of the branch circuit. (3) Lighting fixtures equipped with mogul-base screw-shell lampholders. (4) Lampholders other than the screw-shell type applied within their voltage ratings. (5) Auxiliary equipment of electric discharge lamps. (6) Cord- and plug-connected or permanently connected utilization equipment. (d) 600 Volts Between Conductors. Circuits exceeding 277 volts, nominal, to ground and not exceeding 600 volts, nominal, between conductors shall be permitted to supply: (1) The auxiliary equipment of electric-discharge lamps mounted in permanently installed fixtures where the fixtures are mounted in accordance with one of the following: a. Not less than a height of 22 feet (6.71 m) on poles or similar structures for the illumination of outdoor areas, such as highways, roads, bridges, athletic fields, or parking lots. b. Not less than a height of 18 feet (5.49 m) on other structures, such as tunnels. (2) Cord- and plug-connected or permanently connected utilization equipment. (FPN): See Section 410-78 for auxiliary equipment limitations. Exception No. 1 to (b), (c), and (d) above: For lampholders of infrared industrial heating appliances as provided in Section 422-15(c). Exception No. 2 to (b), (c), and (d) above: For railway properties as described in Section 110-19. 70-38 NATIONAL ELECTRICAL CODE 210-7. Receptacles and Cord Connectors. (a) Grounding Type. Receptacles installed on 15- and 20-ampere branch circuits shall be of the grounding type. Grounding-type receptacles shall be installed only on circuits of the voltage class and current for which they are rated, except as provided in Tables 210-21(b)(2) and (b)(3). Exception: Nongrounding-type receptacles installed in accordance with Section 210-7(d), Exception. (b) To Be Grounded. Receptacles and cord connectors having grounding contacts shall have those contacts effectively grounded. Exception No. 1: Receptacles mounted on portable and vehiclemounted generators in accordance with Section 250-6. Exception No. 2: Ground-fault circuit-interrupter replacement receptacles as permitted by Section 210-7(d), Exception. (c) Methods of Grounding. The grounding contacts of receptacles and cord connectors shall be grounded by connection to the equipment grounding conductor of the circuit supplying the receptacle or cord connector. (FPN): For installation requirements for the reduction of electrical noise, see