xav

0-volt, 20-ampere branch circuit shall be installed to supply receptacle outlets, including those required by 210.52(G)(1) for attached garages and in detached garages with electric power. This circuit shall have no other outlets. Additional branch circuits rated 15 amperes or greater shall be permi...

0-volt, 20-ampere branch circuit shall be installed to supply receptacle outlets, including those required by 210.52(G)(1) for attached garages and in detached garages with electric power. This circuit shall have no other outlets. Additional branch circuits rated 15 amperes or greater shall be permitted to serve receptacle outlets other than those required by 210.52(G)(1). Exception No. 1: This circuit shall be permitted to supply outdoor receptacle outlets. Exception No. 2: Where the 20-ampere circuit supplies a single vehicle bay garage, outlets for other equipment within the same garage shall be permitted to be supplied in accordance with 210.23(B)(1) and (B)(2). 210.12 Arc-Fault Circuit-Interrupter Protection. Arc-fault circuit-interrupter (AFCI) protection shall be installed in accordance with 210.12(B) through (E) by any of the means described in 210.12(A)(1) through (A)(6). The AFCI shall be listed and installed in a readily accessible location. ENHANCED CONTENT Collapse Listed arc-fault circuit-interrupter (AFCI) devices are evaluated in accordance with UL 1699, Standard for Arc-Fault Circuit-Interrupters. Testing methods create or simulate arcing conditions to determine a product’s ability to detect and interrupt arcing faults. The devices are also tested to verify that arc detection is not unduly inhibited by the presence of loads and circuit characteristics that may mask the hazardous arcing condition. The devices are also evaluated to determine resistance to unwanted tripping due to the presence of arcing that occurs in control and utilization equipment under normal operating conditions or to a loading condition that closely mimics an arcing fault, such as that found in a solid-state electronic ballast or a dimmed load. AFCI devices may also be capable of performing other functions such as overcurrent protection, ground-fault circuit interruption, and surge suppression. UL 1699 currently recognizes four types of AFCIs: branch/feeder, cord, outlet circuit, and portable. (The exhibit below provides an example of the required marking indicating the type of AFCI protection.) (Courtesy of Square D by Schneider Electric) AFCI devices have a maximum rating of 20 amperes and are intended for use in 120 volts ac, 60-hertz circuits. Cord AFCIs can be rated up to 30 amperes. Placement of the device in the circuit must be considered when complying with 210.12. Six possible configurations using listed equipment are permitted by the NEC. The objective of the NEC is to provide protection of the entire branch circuit. The configurations may use a single combination-type AFCI at the origin of the circuit, a combination of devices, or a combination of physical protection for part of the circuit and a device-type AFCI located downstream of the origin of the circuit. Where the AFCI is not located at the origin of the circuit, a higher level of physical protection must be provided for branch- circuit conductors from the origin of the branch circuit to the device-type AFCI. Some configurations have length restrictions to the first outlet, based on the size of the conductors (50 feet for 14 AWG and 70 feet for 12 AWG). The table below summarizes the permitted methods of providing AFCI protection. Branch-circuit/feeder-type AFCI devices provide arcing protection against parallel faults. An example of a parallel arcing fault is a cable stapled to a wooden stud where the staple has been driven deeply into the cable jacket, damaging the conductor insulation. Combination-type AFCIs provide parallel arcing protection as well as protection against series arcing, such as could occur in a cord set. AFCI protection is required to protect receptacle outlets, lighting outlets, smoke alarm outlets, and other outlets. See the definition of outlet in Article 100. Because circuits are often shared between a bedroom and other areas such as closets and hallways, providing AFCI protection on the complete circuit would comply with 210.12. Providing AFCI protection on other circuits, or locations other than those specified in 201.12(B) through (D), is not prohibited. (A) Means of Protection. AFCI protection shall be provided by any of the following means: * (1) A listed combination-type AFCI installed to provide protection of the entire branch circuit. * (2) A listed branch/feeder-type AFCI installed at the origin of the branchcircuit in combination with a listed outlet branch-circuit-type AFCI installed on the branch circuit at the first outlet box, which shall be marked to indicate that it is the first outlet of the branch circuit. * (3) A listed supplemental arc protection circuit breaker installed at the origin of the branch circuit in combination with a listed outlet branch- circuit-type AFCI installed on the branch circuit at the first outlet box if all of the following conditions are met: o a. The branch-circuit wiring shall be continuous from the branch- circuit overcurrent device to the outlet branch-circuit AFCI. o b. The maximum length of the branch-circuit wiring from the branch- circuit overcurrent device to the first outlet shall not exceed 15.2 m (50 ft) for a 14 AWG conductor or 21.3 m (70 ft) for a 12 AWG conductor. o c. The first outlet box shall be marked to indicate that it is the first outlet of the branch circuit. * (4) A listed outlet branch-circuit-type AFCI installed on the branch circuit at the first outlet in combination with a listed branch-circuit overcurrent protective device if all of the following conditions are met: o a. The branch-circuit wiring shall be continuous from the branch- circuit overcurrent device to the outlet branch-circuit AFCI. o b. The maximum length of the branch-circuit wiring from the branch- circuit overcurrent device to the first outlet shall not exceed 15.2 m (50 ft) for a 14 AWG conductor or 21.3 m (70 ft) for a 12 AWG conductor. o c. The first outlet box shall be marked to indicate that it is the first outlet of the branch circuit. o d. The combination of the branch-circuit overcurrent device and outlet branch-circuit AFCI shall be identified as meeting the requirements for a system combination-type AFCI and listed as such. * (5) If metal raceway, metal wireways, metal auxiliary gutters, or Type MC or Type AC cable meeting the applicable requirements of 250.118, with metal boxes, metal conduit bodies, and metal enclosures are installed for the portion of the branch circuit between the branch-circuit overcurrent device and the first outlet, it shall be permitted to install a listed outlet branch-circuit-type AFCI at the first outlet to provide protection for the remaining portion of the branch circuit. * (6) Where a listed metal or nonmetallic conduit or tubing or Type MC cable is encased in not less than 50 mm (2 in.) of concrete for the portion of the branch circuit between the branch-circuit overcurrent device and the first outlet, it shall be permitted to install a listed outlet branch-circuit- type AFCI at the first outlet to provide protection for the remaining portion of the branch circuit. Informational Note: See UL 1699-2011, Standard for Arc-Fault Circuit-Interrupters, for information on combination-type and branch/feeder-type AFCI devices. See UL Subject 1699A, Outline of Investigation for Outlet Branch Circuit Arc-Fault Circuit- Interrupters, for information on outlet branch-circuit type AFCI devices. See UL Subject 1699C, Outline of Investigation for System Combination Arc-Fault Circuit Interrupters, for information on system combination AFCIs. (B) Dwelling Units. All 120-volt, single-phase, 10-, 15-, and 20-ampere branch circuits supplying outlets or devices installed in the following locations shall be protected by any of the means described in 210.12(A)(1) through (A)(6): * (1) Kitchens * (2) Family rooms * (3) Dining rooms * (4) Living rooms * (5) Parlors * (6) Libraries * (7) Dens * (8) Bedrooms * (9) Sunrooms * (10) Recreation rooms * (11) Closets * (12) Hallways * (13) Laundry areas * (14) Similar areas Exception No. 1: AFCI protection shall not be required for an individual branch circuit supplying a fire alarm system installed in accordance with 760.41(B) or 760.121(B). The branch circuit shall be installed in a metal raceway, metal auxiliary gutter, steel- armored cable, or Type MC or Type AC cable meeting the applicable requirements of 250.118, with metal boxes, conduit bodies, and enclosures. Exception No. 2: AFCI protection shall not be required for the individual branch circuit supplying an outlet for arc welding equipment in a dwelling unit until January 1, 2025. Informational Note No. 1: See NFPA 72-2022, National Fire Alarm and Signaling Code, 29.9.4(5), for information on secondary power source requirements for smoke alarms installed in dwelling units. Informational Note No. 2: See 760.41(B) and 760.121(B) for power source requirements for fire alarm systems. (C) Dormitory Units. All 120-volt, single-phase, 10-, 15-, and 20-ampere branch circuits supplying outlets or devices installed in the following locations shall be protected by any of the means described in 210.12(A)(1) through (A)(6): * (1) Bedrooms * (2) Living rooms * (3) Hallways * (4) Closets * (5) Bathrooms * (6) Similar rooms (D) Other Occupancies. All 120-volt, single-phase, 10-, 15-, and 20-ampere branch circuits supplying outlets or devices installed in the following locations shall be protected by any of the means described in 210.12(A)(1) through (A)(6): * (1) Guest rooms and guest suites of hotels and motels * (2) Areas used exclusively as patient sleeping rooms in nursing homes and limited-care facilities * (3) Areas designed for use exclusively as sleeping quarters in fire stations, police stations, ambulance stations, rescue stations, ranger stations, and similar locations (E) Branch Circuit Wiring Extensions, Modifications, or Replacements. If branch-circuit wiring for any of the areas specified in 210.12(B), (C), or (D) is modified, replaced, or extended, the branch circuit shall be protected by one of the following: * (1) By any of the means described in 210.12(A)(1) through (A)(6) * (2) A listed outlet branch-circuit-type AFCI located at the first receptacle outlet of the existing branch circuit Exception: AFCI protection shall not be required where the extension of the existing branch-circuit conductors is not more than 1.8 m (6 ft) and does not include any additional outlets or devices, other than splicing devices. This measurement shall not include the conductors inside an enclosure, cabinet, or junction box. 210.13 Ground-Fault Protection of Equipment. Each branch-circuit disconnecting means rated 1000 amperes or more and installed on solidly grounded wye electrical systems of more than 150 volts to ground, but not exceeding 1000 volts phase-to-phase, shall be provided with ground-fault protection of equipment in accordance with 230.95. Informational Note: See 517.17 for requirements on buildings that contain health care occupancies. Exception No. 1: This section shall not apply to a disconnecting means for a continuous industrial process where a nonorderly shutdown will introduce additional or increased hazards. Exception No. 2: This section shall not apply if ground-fault protection of equipment is provided on the supply side of the branch circuit and on the load side of any transformer supplying the branch circuit. ENHANCED CONTENT Collapse Exceptions are provided for continuous industrial processes where shutdown could introduce additional or increased hazards and for installations where ground-fault protection is provided upstream of the branch circuit on the load side of a transformer supplying the branch circuit. See also 230.95 and its enhanced content for more information on ground- fault protection of equipment. 210.17 Guest Rooms and Guest Suites. Guest rooms and guest suites in the following occupancies that are provided with permanent provisions for cooking shall have branch circuits installed to meet the rules for dwelling units: * (1) Hotels * (2) Motels * (3) Assisted living facilities Informational Note No. 1: See 210.11(C)(2) and 210.52(F), Exception No. 2, for information on laundry branch circuits and receptacle outlets. Informational Note No. 2: See NFPA 101-2021, Life Safety Code, 3.3.198.12 and A.3.3.198.12(5), for the definition of assisted living facilities. ENHANCED CONTENT Collapse The guest suite configuration shown below triggers the requirement to install the branch-circuit wiring in the unit using all the branch-circuit requirements that apply to dwelling units. Part II. Branch-Circuit Ratings 210.18 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 10, 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 No. 1: Multioutlet branch circuits greater than 50 amperes shall be permitted to supply nonlighting outlet loads in locations where conditions of maintenance and supervision ensure that only qualified persons service the equipment. Exception No. 2: Branch circuits rated 10 amperes shall not supply receptacle outlets. ENHANCED CONTENT Collapse The rating of a branch circuit is determined by the rating of the overcurrent protective device (OCPD), not by the ampacity of the circuit conductors. An increase in conductor ampacity from 20 amperes (12 AWG) to 30 amperes (10 AWG) for any reason does not change the rating of the circuit. If the rating of the branch-circuit OCPD is 20 amperes, then the rating of the circuit is 20 amperes. Exception No. 1. A common practice at industrial facilities is to provide several single receptacles with ratings of 50 amperes or higher on a single branch circuit to allow quick relocation of equipment (such as electric welders) for production or maintenance. Generally, only one piece of equipment at a time is supplied from this type of receptacle circuit. The type of receptacle used in this situation is generally a pin-and-sleeve receptacle. 210.19 Conductors - Minimum Ampacity and Size. Branch-circuit conductors for circuits not exceeding 1000 volts ac or 1500 volts dc shall be sized in accordance with 210.19(A) through (D). Informational Note: Conductors for branch circuits as defined in Article 100, sized to prevent a voltage drop exceeding 3 percent at the farthest outlet of power, heating, and lighting loads, or combinations of such loads, and where the maximum total voltage drop on both feeders and branch circuits to the farthest outlet does not exceed 5 percent, provide reasonable efficiency of operation. See 215.2(A)(2), Informational Note No. 2, for information on voltage drop on feeder conductors. ENHANCED CONTENT Collapse Excessive voltage drop in supply conductors can cause inefficient operation or malfunction of electrical equipment. Undervoltage conditions reduce the capability and reliability of motors, lighting sources, heaters, and solid-state equipment. It may be necessary to compensate for this with an installation beyond the minimum requirements. (A) General. Branch-circuit conductors shall have an ampacity not less than the larger of the following and comply with 110.14(C) for equipment terminations: * (1) Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the minimum branch-circuit conductor size shall have an ampacity not less than the noncontinuous load plus 125 percent of the continuous load in accordance with 310.14. Exception to (1): If the assembly, including the overcurrent devices protecting the branch circuits, is listed for operation at 100 percent of its rating, the ampacity of the branch-circuit conductors shall be permitted to be not less than the sum of the continuous load plus the noncontinuous load in accordance with 110.14(C). * (2) The minimum branch-circuit conductor size shall have an ampacity not less than the maximum load to be served after the application of any adjustment or correction factors in accordance with 310.15. Exception to (1) and (2): Where a portion of a branch circuit is connected at both its supply and load ends to separately installed pressure connections as covered in 110.14(C)(2), an allowable ampacity in accordance with 310.15 not less than the sum of the continuous load plus the noncontinuous load shall be permitted. No portion of a branch circuit installed under this exception shall extend into an enclosure containing either the branch-circuit supply or the branch-circuit load terminations. ENHANCED CONTENT Collapse Conductors of branch circuits must be able to supply power to loads without overheating. The minimum conductor size and ampacity must be based on the larger of the following criteria: * The noncontinuous load plus 125 percent of the continuous load * Not less than the maximum load to be served after the application of any adjustment or correction factors It is not necessary to apply the additional 25 percent continuous load to the adjustment and correction factor calculations of 210.19(A)(2). For sizing of the neutral conductor load, see 220.61. (B) Branch Circuits with More than One Receptacle. Conductors of branch circuits supplying more than one receptacle for cord- and-plug-connected portable loads shall have an ampacity of not less than the rating of the branch circuit. ENHANCED CONTENT Collapse The loading of branch-circuit conductors that supply receptacles for cord-and- plug-connected portable loads is unpredictable. The circuit conductors are required to have an ampacity that is not less than the rating of the branch circuit. The rating of the branch circuit is the rating of the overcurrent device according to 210.18. (C) Household Ranges and Cooking Appliances. Branch-circuit conductors supplying household ranges, wall-mounted ovens, counter-mounted cooking units, and other household cooking appliances shall have an ampacity not less than the rating of the branch circuit and not less than the maximum load to be served. For ranges of 83/4 kW or more rating, the minimum branch-circuit rating shall be 40 amperes. Exception No. 1: Conductors tapped from a branch circuit not exceeding 50 amperes supplying electric ranges, wall-mounted electric ovens, and counter-mounted electric cooking units shall have an ampacity of not less than 20 amperes and shall be sufficient for the load to be served. These tap conductors include any conductors that are a part of the leads supplied with the appliance that are smaller than the branch-circuit conductors. The taps shall not be longer than necessary for servicing the appliance. Exception No. 2: The neutral conductor of a 3-wire branch circuit supplying a household electric range, a wall-mounted oven, or a counter-mounted cooking unit shall be permitted to be smaller than the ungrounded conductors where the maximum demand of a range of 83/4 kW or more rating has been calculated according to Column C of Table 220.55, but such conductor shall have an ampacity of not less than 70 percent of the branch-circuit rating and shall not be smaller than 10 AWG. ENHANCED CONTENT Collapse Exception No. 1. Both factory-installed pigtails and field-installed conductors are considered to be tap conductors in the application of Exception No. 1. This exception permits a 20-ampere tap conductor from a range, oven, or cooking unit to be connected to a 50-ampere branch circuit as illustrated in the exhibit below. Exception No. 2. Column C of Table 220.55 indicates that the maximum demand for one range (not over 12-kilowatt rating) is 8 kilowatts (8000 VA; 8000 VA ö 240 V = 33.3 A). The ampacity of an 8 AWG copper conductor from the 60øC column of Table 310.16 is 40 amperes, and this conductor may be used for the range branch circuit. According to Exception No. 2, the neutral of this 3-wire circuit can be smaller than 8 AWG but not smaller than 10 AWG. A 10 AWG conductor has an ampacity of 30 amperes (30 amperes is more than 70 percent of 40 amperes). The maximum demand for the neutral of an 8- kilowatt range circuit seldom exceeds 25 amperes because the only line-to- neutral connected loads are lights, clocks, timers, and the heating elements of some ranges when the control is adjusted to the low-heat setting. (D) Other Loads. Branch-circuit conductors that supply loads other than those specified in 210.3 and other than cooking appliances as covered in 210.19(C) shall have an ampacity sufficient for the loads served and shall not be smaller than 14 AWG. Exception No. 1: Tap conductors shall have an ampacity sufficient for the load served. In addition, they shall have an ampacity of not less than 15 for circuits rated less than 40 amperes and not less than 20 for circuits rated at 40 or 50 amperes and only where these tap conductors supply any of the following loads: * (1) Individual lampholders or luminaires with taps extending not longer than 450 mm (18 in.) beyond any portion of the lampholder or luminaire * (2) A luminaire having tap conductors in accordance with 410.117 * (3) Individual outlets, other than receptacle outlets, with taps not over 450 mm (18 in.) long * (4) Infrared lamp industrial heating appliances * (5) Nonheating leads of deicing and snow-melting cables and mats Exception No. 2: Fixture wires and flexible cords shall be permitted to be smaller than 14 AWG as permitted by 240.5. 210.20 Overcurrent Protection. Branch-circuit conductors and equipment for circuits not exceeding 1000 volts ac or 1500 volts dc shall be protected by overcurrent protective devices that have a rating or setting that complies with 210.20(A) through (D). (A) Continuous and Noncontinuous Loads. Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the rating of the overcurrent device shall not be less than the noncontinuous load plus 125 percent of the continuous load. Exception: Where the assembly, including the overcurrent devices protecting the branch circuit(s), is listed for operation at 100 percent of its rating, the ampere rating of the overcurrent device shall be permitted to be not less than the sum of the continuous load plus the noncontinuous load. ENHANCED CONTENT Collapse The exhibit below is an example of a calculation of a minimum branch-circuit rating for a continuous load (store lighting). The 125 percent requirement from 210.20(A) has been applied to the 16 amperes of continuous load, making it permissible to use a 20-ampere rated overcurrent device in this application. Section 210.19(A)(1) requires that the circuit conductors have an ampacity based on the larger of these two criteria: * Not less than the sum of the noncontinuous load plus 125 percent of the continuous load * Not less than the maximum load to be served after the application of any adjustment or correction factors However, the rating of the overcurrent device cannot exceed the sum of the noncontinuous load plus 125 percent of the continuous load. For sizing of the neutral conductor load, see 220.61. (B) Conductor Protection. Conductors shall be protected in accordance with 240.4. Flexible cords and fixture wires shall be protected in accordance with 240.5. (C) Equipment. The rating or setting of the overcurrent protective device shall not exceed that specified in the applicable articles referenced in Table 240.3 for equipment. (D) Outlet Devices. The rating or setting shall not exceed that specified in 210.21 for outlet devices. 210.21 Outlet Devices. Outlet devices shall have an ampere rating that is not less than the load to be served and shall comply with 210.21(A) and (B). (A) Lampholders. Where connected to a branch circuit having a rating in excess of 20 amperes, lampholders shall be of the heavy-duty type. A heavy-duty lampholder shall have a rating of not less than 660 watts if of the admedium type, or not less than 750 watts if of any other type. (B) Receptacles. (1) Single Receptacle on an Individual Branch Circuit. A single receptacle installed on an individua