2023 NEC Significant Code Changes Part 3 Help

(A)  Voltage.

All areas Areas designated as hazardous (classified) locations or determined to be unclassified shall be properly documented, on an area classification drawing and other associated documentation. This documentation shall be available to the authority having jurisdiction (AHJ) and those authorized to design, install, inspect, maintain, or operate electrical equipment at the location.

Informational Note No. 1: See the following standards for additional information on the classification of locations:

 NFPA 30-2021, Flammable and Combustible Liquids Code

NFPA 32-2016, Standard for Drycleaning Facilities

NFPA 33-2021, Standard for Spray Application Using Flammable or Combustible Materials

NFPA 34-2021, Standard for Dipping, Coating, and Printing Processes Using Flammable or Combustible Liquids

NFPA 35-2021, Standard for the Manufacture of Organic Coatings

NFPA 36-2021, Standard for Solvent Extraction Plants

NFPA 45-2019, Standard on Fire Protection for Laboratories Using Chemicals

NFPA 55-2020, Compressed Gases and Cryogenic Fluids Code

NFPA 58-2020, Liquefied Petroleum Gas Code

NFPA 59-2021, Utility LP-Gas Plant Code

NFPA 497-2021, Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas

NFPA 499-2021, Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas

NFPA 820-2020, Standard for Fire Protection in Wastewater Treatment and Collection Facilities

ANSI/API RP 500-2012, Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I, Division 1 and Division 2

ISA-12.10-1988, Area Classification in Hazardous (Classified) Dust Locations

(a) Combustible Fibers/Flyings. Locations where nonmetal combustible fibers/flyings are in the air under normal operating conditions in quantities sufficient to produce explosible mixtures or where mechanical failure or abnormal operation of machinery or equipment might cause combustible fibers/flyings to be produced and might also provide a source of ignition through simultaneous failure of electrical equipment, through operation of protection devices, or from other causes shall be classified as Class III, Division 1. Locations where metal combustible fibers/flyings are present shall be classified as Class II, Division 1, Group E.

Informational Note No. 1: Such locations usually include some parts of rayon, cotton, and other textile mills; associated manufacturing and processing plants; cotton gins and cotton-seed mills; flax-processing plants; clothing manufacturing plants; woodworking plants; and establishments and industries involving similar hazardous processes or conditions.

Informational Note No. 2: Combustible fibers/flyings include flat platelet-shaped particulates, such as metal flakes, and fibrous board, such as particle board.

(D)  Temperature.

(1)  Class I Temperature.

The temperature marking specified in 500.8(C) shall not exceed the autoignition temperature of the specific gas or vapor to be encountered.

Informational Note: See NFPA 497-2021, Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas, for information on autoignition temperatures of gases and vapors.

(2)  Class II Temperature.

The temperature marking specified in 500.8(C) shall be less than the ignition temperature of the specific dust or metal fiber/flying to be encountered. For organic dusts that may might dehydrate or carbonize, the temperature marking shall not exceed the lower of either the ignition temperature or 165°C (329°F).

Informational Note: See NFPA 499-2021, Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas, for minimum ignition temperatures of specific dusts.

(3)  Class III Temperature.

The temperature marking specified in 500.8(C) shall be less than the ignition temperature of the specific fiber/flying to be encountered, except as specified in 500.8(D)(3)(a) or (D)(3)(b).

For nonmetal combustible fibers/flyings that might dehydrate or carbonize, the temperature marking shall not exceed the lower of either the ignition temperature or 165°C (329°F).

When ignitable fibers/flyings are present, the maximum surface temperatures under operating conditions shall not exceed 165°C (329°F) for equipment that is not subject to overloading, and 120°C (248°F) for equipment (such as motors or power transformers) that might be overloaded.

(2)  Zone Equipment.

Equipment meeting one or more of the protection techniques described in 505.8 shall be marked with all of the following in the order shown:

• Class I (equipment shall be permitted to omit the Class I marking)shall be an optional marking. If it is included in the equipment marking, the Class I marking shall precede the zone marking.
• Zone in accordance with Table 505.9(C)(2)(4)Chapter 9, Table 13.

Part I.  General

512.1  Scope.

This article covers cannabis oil preparatory equipment, extraction equipment, booths, post-processing equipment, and systems using flammable materials (flammable gas, flammable liquid–produced vapor, combustible liquid–produced vapor) in commercial and industrial facilities.

 Note: See NEC for Complete Text

515.10  Special Equipment — Gasoline Motor Fuel Dispensers.

Where In addition to the requirements of this article, dispensers for gasoline or other volatile flammable liquids or liquefied liquified flammable gases are dispensed at bulk stations, the requirements of 514.1 shall apply shall comply with the requirements for motor fuel dispensing facilities, as applicable, except as modified by this article.

Article  517  Health Care Facilities

Part I.  General

517.1 Scope.

This article applies to electrical construction and installation criteria in health care facilities that provide services to human beings.

The requirements in Parts II and III not only apply to single-function buildings but are also intended to be individually applied to their respective forms of occupancy within a multifunction building (e.g., a doctor’s examining room located within a limited care facility would be required to meet 517.10).

Note: See NEC for Complete Text

517.6  Patient Care–Related Electrical Equipment.

The reconditioning requirements of this Code shall not apply to patient care–related electrical equipment.

Informational Note No. 1: Patient care–related electrical equipment is differentiated from electrical equipment as described in 110.21(A)(2).

Informational Note No. 2: If patient care–related electrical equipment is relocated, it is expected to be recommissioned or recertified in accordance with the U.S. Federal Food, Drug, and Cosmetic Act (FDCA).

517.13  Equipment Grounding Conductor for Receptacles and Fixed Electrical Equipment in Patient Care Spaces.

Wiring in serving patient care spaces shall comply with the requirements of 517.13(A) and (B).

Exception: Luminaires more than 2.3 m (71⁄2 ft) above the floor and switches located outside of the patient care vicinity shall be permitted to be connected to an equipment grounding return path complying with the requirements of 517.13(A) or (B).

(A)  Wiring Methods.

All branch circuits serving patient care spaces shall be provided with an effective ground-fault current path by installation in a metal raceway system or a cable having a metallic armor or sheath assembly. The metal raceway system, metallic cable armor, or sheath assembly shall itself qualify as an equipment grounding conductor in accordance with 250.118.

(B)  Insulated Equipment Grounding Conductors and Insulated Equipment Bonding Jumpers.

(1)  General.

The following shall be directly connected to an An insulated copper equipment grounding conductor that is clearly identified along its entire length by green insulation and installed with the branch circuit conductors in within the wiring methods as provided in method in accordance with517.13(A) shall be directly connected to the following:

The grounding Grounding terminals of all receptacles other than isolated ground receptacles

Metal outlet boxes, metal device boxes, or metal enclosures

All non Non–current-carrying conductive surfaces of fixed electrical equipment likely to become energized that are subject to personal contact, operating at over 100 volts

Metal faceplates, by means of a metal mounting screw(s) securing the faceplate to a metal yoke or strap of a receptacle or to a metal outlet box

Exception No. 1: For other than isolated ground receptacles, an insulated equipment bonding jumper that directly connects to the equipment grounding conductor is shall be permitted to connect the box and receptacle(s) to the equipment grounding conductor. Isolated ground receptacles shall be connected in accordance with 517.16.

Exception No. 2: Luminaires more than 2.3 m (71⁄2 ft) above the floor and switches located outside of the patient care vicinity shall be permitted to be connected to an equipment grounding return path complying with 517.13(A) or (B)Metal faceplates shall be connected to an effective ground-fault current path by means of a metal mounting screw(s) securing the faceplate to a metal yoke or strap of a receptacle or to a metal outlet box.

517.22  Demand Factors.

Demand factors for receptacle loads supplied by general-use receptacles and individual branch circuits not exceeding 150 volts to ground and installed in Category 1, Category 2, Category 3, and Category 4 patient care spaces shall be permitted to be applied in accordance with 517.22(A) and (B)220.110.

Informational Note: See Article 100 for the definitions of patient care space categories.

517.30  Sources of Power.

(A)  Two Independent Power Sources.

Essential electrical systems shall have a minimum of the following two independent sources of power: a normal source generally supplying the entire electrical system and one or more alternate sources for use when the normal source is interrupted. [99:6.7.1.1.2]Essential electrical systems (EES) shall have two or more independent sources (or sets of sources). One on-site source (or sets of sources) shall be sized to supply the entire EES. The other independent source (or sets of sources) shall be sized to supply the entire EES and shall be permitted to be located on-site or off-site. Additional sources other than the first two independent sources shall be permitted to be sized to supply the intended load.

Informational Note: An example of a set of sources may be several generators that combined serve the entire EES.

(B)  Types of Normal Power Sources.

Normal power sources shall be permitted to be any of the following:

Utility supply power

Generation units

Health care microgrid

Fuel cells

(B)  Types of Alternate Power Sources for the EES.

Alternate power Power sources for the EES shall be permitted to be any of those specified in 517.30(B)(1)517.30(C)(1) through (C)(5)(B)(5).

Part V.   X-Ray Installations Diagnostic Imaging and Therapeutic Equipment Installations

(A)  Examples.

Assembly occupancies shall include, but not be limited to, the following:

• Armories
• Assembly halls
• Auditoriums
• Bowling lanes
• Casinos and gaming facilities
• Club rooms
• Conference rooms
• Courtrooms
• Dance halls
• Dining and drinking facilities
• Exhibition halls
• Gymnasiums
• Mortuary chapels
• Multipurpose rooms
• Museums
• Places of awaiting transportation
• Places of religious worship
• Pool rooms
• Restaurants
• Skating rinks

518.4(A) General. The wiring method shall qualify as an equipment grounding conductor in accordance with 250.118 or shall contain an equipment grounding conductor sized in accordance with Table 250.122  and shall be any of the following:

(1) Metal raceways

(2) Flexible metal raceways

(3) Nonmetallic raceways encased in not less than 50 mm (2 in.) of concrete

(4) Type MI, Type MC, or Type AC cable

518.4(B) Communications, Signaling Systems, Data Systems, Fire Alarm Systems, and Systems Less Than 120 Volts, Nominal.

 Fixed wiring methods for specific installations shall be as follows:

(1) Audio signal processing, amplification, and reproduction equipment — 640.9

(2) Communications systems — Part IV of Article 805 and Part VI of Article 840

(3) Class 2 and Class 3 remote control and signaling circuits — Article 725, Part III

(4) Class 2 circuits that transmit power, data, or both to a powered device

518.5  Supply.

Portable switchboards and portable power distribution equipment shall be supplied only from listed power outlets of sufficient voltage and ampere rating. Such power outlets shall be protected by overcurrent devices. Such overcurrent devices and power outlets shall not be accessible to the general public. Provisions for connection of an equipment grounding conductor shall be provided. The neutral conductor of feeders supplying solid-state phase-control, 3-phase, 4-wire dimmer systems shall be considered a current-carrying conductor for purposes of ampacity adjustment. The neutral conductor of feeders supplying solid-state sine-wave, 3-phase, 4-wire dimming systems shall not be considered a current-carrying conductor for purposes of ampacity adjustment.

Portable switchboards, portable power distribution equipment, and commercial appliance outlet centers shall be installed in accordance with 518.5(A) through (C).

Note: See NEC for Complete Text

530.1  Scope.

The requirements of this article shall apply to motion picture and television studios and motion picture studios using either film or electronic cameras, in facilities and locations staffed by qualified personnel, except as provided in 520.1., and exchanges, factories, laboratories, stages, or a portion of the building in which film or tape more than 22 mm (7⁄8 in.) in width is exposed, developed, printed, cut, edited, rewound, repaired, or stored. Such occupancies shall include those using either electronic or film cameras for image capture.

Informational Note: For methods of protecting against cellulose nitrate film hazards, see NFPA 40-2019, Standard for the Storage and Handling of Cellulose Nitrate Film See NFPA 40-2019, Standard for the Storage and Handling of Cellulose Nitrate Film, for methods of protecting against cellulose nitrate film hazards.

Note: See NEC for Complete Text

547.26  Physical Protection.

All electrical wiring and equipment subject to physical damage shall be protected.

Nonmetallic cables shall not be permitted to be concealed within walls and above ceilings of buildings (i.e., offices, lunchrooms, ancillary areas, etc.) or portions thereof, which are contiguous with or physically adjoined to livestock confinement areas.

Informational Note: Rodents and other pests are common around such installations and will damage nonmetallic cable by chewing the cable jacket and conductor insulation concealed within walls and ceilings of livestock containment areas of agricultural buildings.

547.44  Equipotential Planes and Bonding of Equipotential Planes.

The installation and bonding of equipotential planes shall comply with 547.10(A)547.44(A)547.44(A) and (B). For the purposes of this section, the term livestock shall not include poultry.

(A)  Where Required.

Equipotential planes shall be installed where required in 547.10(A)(1) and (A)(2). required in the following areas:

(1)  Indoors.

Equipotential planes shall be installed in confinement areas with concrete floors where metallic equipment is located that may become energized and is accessible to livestock.

(2)  Outdoors.

Equipotential planes shall be installed in concrete slabs where metallic equipment is located that may become energized and is accessible to livestock.

The equipotential plane shall encompass the area where the livestock stands while accessing metallic equipment that may become energized.

Global SCR-124

Equipotential planes shall be connected bonded to the grounding electrode system or an equipment grounding terminal in any panelboard of the electrical grounding system associated with the equipotential plane. The bonding conductor shall be solid copper, insulated, covered or bare, and not smaller than 8 AWG. The means of bonding to wire mesh or conductive elements shall be by pressure connectors or clamps of brass, copper, copper alloy, or an equally substantial other approved means. Slatted floors that are supported by structures that are a part of an equipotential plane shall not require bonding.

Informational Note No. 1: See (ASEA/ASABE) EP473.2-2001 (R2015), Equipotential Planes in Animal Containment Areas, for methods to establish equipotential planes.

Informational Note No. 2: See (ASEA/ASABE) EP342.3-2010 (R2015), Safety for Electrically Heated Livestock Waterers, for methods for safe installation of livestock waterers.

Informational Note No. 3: Low grounding electrode system resistances may reduce voltage differences in livestock facilities.

(A)  Mobile Home Service Equipment.

The mobile home service equipment shall be located adjacent to the mobile home and not not be mounted in or on the mobile home. The service equipment shall be located in sight from and not more than 9.0 m (30 ft) from the exterior wall of shall be rated not less than that required in accordance with 550.32(C), mounted in a readily accessible outdoor location, and within sight from the mobile home it serves. The mobile home service equipment disconnect shall be permitted to be located elsewhere on the premises, if a disconnecting means suitable for use as service equipment is located within sight from and not more than 9.0 m (30 ft) from the exterior wall of the mobile home it serves and is rated not less than that required for service equipment in accordance with 550.32(C)used as the emergency disconnect in accordance with 230.85. Grounding at the disconnecting means shall be in accordance with 250.32.

551.3  Electrical Datum Plane Distances.

The electrical datum plane distance(s) is determined by the normal high water level and encompasses the areas subject to tidal movement and areas in which the water level is affected by the conditions such as climate (rain or snowfall) or by human intervention (the opening and closing of dams or floodgates). The distance does not consider extremes due to natural or manmade disasters.

(A)  Areas Subject to Tidal Fluctuations.

In land areas subject to tidal fluctuation, the electrical datum plane shall be a horizontal plane that is 606 mm (2 ft) above the highest high tide level for the area occurring under normal circumstances.

(B)  Areas Not Subject to Tidal Fluctuations.

In land areas not subject to tidal fluctuation, the electrical datum plane shall be a horizontal plane that is 606 mm (2 ft) above the normal high water level for the area occurring under normal circumstances.

(D)   Loss of Ground Device.

A device listed to indicate loss of ground shall be installed directly adjacent to the recreational vehicle entrance so that the external indicator display is visible prior to entry into the recreational vehicle.Each recreational vehicle shall have a listed grounding monitor interrupter permanently installed between the feeder assembly connection to the vehicle and before either a transfer switch if installed or the panelboard. The device shall provide a continuous visible or audible signal response to the loss of ground.This requirement shall become effective January 1, 2026.

555.4  Location of Service Equipment.

The service equipment for a floating building, dock, or marina shall be located on land no closer than 1.5 m (5 ft) horizontally from and adjacent to the structure served, but not on or in the structure itself or any other floating structure. Service equipment shall be elevated a minimum of 300 mm (12 in.) above the electrical datum plane.

555.6  Load Calculations for Service and Feeder Conductors.

General lighting and other loads shall be calculated in accordance with Part III of Article 220, and, in addition, the demand factors set forth in Table 555.6220.120 shall be permitted for each service and/or feeder circuit supplying receptacles that provide shore power for boats. These calculations shall be permitted to be modified as indicated in notes (1) and (2) to Table 555.6. Where demand factors of Table 555.6 are applied, the demand factor specified in 220.61(B) shall not be permitted.

555.14  Equipotential Planes and Bonding of Equipotential Planes.

An equipotential plane shall be installed where required in this section to mitigate step and touch voltages at electrical equipment. The parts specified in this section shall be bonded together and to the electrical grounding system. The bonding conductor shall be solid copper conductors; insulated, covered, or bare; not smaller than 8 AWG.

(A)  Areas Requiring Equipotential Planes.

Equipotential planes shall be installed adjacent to all outdoor service equipment or disconnecting means that control equipment in or on water where the following conditions exist:

• Where the system voltage exceeds 250 volts to ground
• Where the equipment is located within 3 m (10 ft) of the body of water

The equipotential plane shall include all metallic enclosures and controls that are likely to become energized and are accessible to personnel. The equipotential plane shall encompass the area around the equipment and shall extend from the area directly below the equipment out not less than 900 mm (36 in.) in all directions from which a person would be able to stand and come in contact with the equipment.

(B)  Areas Not Requiring Equipotential Planes.

Equipotential planes shall not be required for the controlled utilization equipment on the docking facility or floating building supplied by the service equipment or disconnecting means.

555.15  Replacement of Equipment.

When modifications or replacements of electrical enclosures, devices, or wiring methods are necessary on a docking facility, they shall be required to comply with the requirements of this Code, and the installation shall require an inspection of the  circuit.  lExisting equipment that has been  damaged  shall be identified, documented, and repaired by a qualified person to the minimum requirements of the edition of this Code to which it was originally installed.

(E)  Leakage Current Measurement Device.

Where more than three receptacles supply shore power to boats, a listed leakage current measurement device for use in marina applications shall be available and be used to determine leakage current from each boat that will utilize shore power. The listing requirement for the leakage current measurement device for use in marina applications shall become effective January 1, 2026.

Informational Note No. 1: Leakage current measurement will provide the capability to determine when an individual boat has defective wiring or other problems contributing to hazardous voltage and current. The use of a test device will allow the facility operator to identify a boat that is creating problems. In some cases a single boat may could cause an upstream GFPE device protecting a feeder to operate even though multiple boats are supplied from the same feeder. The use of a test device will help the facility operator prevent a particular boat from contributing to hazardous voltage and current in the marina area.

Informational Note No. 2: An annual test of each boat with the leakage current measurement device is a prudent step toward determining if a boat has defective wiring that may could be contributing hazardous voltage and current. Where the leakage current measurement device reveals that a boat is contributing hazardous voltage and current, repairs should be made to the boat before it is permitted to utilize shore power.

Exception: Where the shore power equipment includes a leakage indicator and leakage alarm, a separate leakage test device shall not be required.

555.36  Disconnecting Means for Shore Power Connection(s).

Disconnecting means shall be provided to isolate each boat from its supply connection(s).

(A)  Type.

The disconnecting means shall consist of a circuit breaker, switch, or both, and shall be properly identified as to which receptacle it controls.

(B)  Location.

The disconnecting means shall be readily accessible, located not more than 762 mm (30 in.) from the receptacle it controls, and shall be located in the supply circuit ahead of the receptacle. Circuit breakers or switches located in marina power outlets complying with this section shall be permitted as the disconnecting means.

(C)  Emergency Electrical Disconnect.

Each marina power outlet or enclosure that provides shore power to boats shall be provided with a listed emergency shutoff device or electrical disconnect that is clearly marked “Emergency Shutoff” in accordance with 110.22(A). The emergency shutoff device or electrical disconnect shall be within sight of the marina power outlet or other enclosure that provides shore power to boats, readily accessible, externally operable, manually resettable, and listed for use in wet locations. The emergency shutoff device or electrical disconnect shall de-energize the power supply to all circuits supplied by the marina power outlet(s) or enclosure(s) that provide shore power to boats. A circuit breaker handle shall not be used for this purpose.

555.38  Luminaires.

(A)  General.

All luminaires and retrofit kits shall be listed and identified for use in their intended environment. Luminaires and their supply connections shall be secured to structural elements of the marina to limit damage from watercraft and prevent entanglement of and interaction with sea life.

(B)  Underwater Luminaires.

Luminaires installed below the highest high tide level or electrical datum plane and likely to be periodically submersed shall be limited to those  luminaires that comply with the following:

Identified as submersible

Operate below the low-voltage contact limit defined in Article 100

Supplied by an isolating transformer or power supply in accordance with 680.23(A)(2)

(F)  Lamp Protection.

All lamps for general illumination shall be protected from accidental contact or breakage by a suitable luminaire or lamp holder with a guard.

Brass shell, paper-lined sockets, or other metal-cased sockets Metal guarded sockets shall not be used unless the shell metal guard is connected to the circuit equipment grounding conductor.

(A)  Required Branch Circuit.

Each commercial building and each commercial occupancy accessible to pedestrians shall be provided with at least one outlet in an accessible location at each entrance to each tenant space for sign or outline lighting system use. The outlet(s) shall be supplied by a branch circuit rated at least 20 amperes that supplies no other load. A sign or outline lighting outlet shall not be required at entrances for deliveries, service corridors, or service hallways that are intended to be used only by service personnel or employees.

Exception No. 1: A sign or outline lighting outlet shall not be required at entrances for deliveries, service corridors, or service hallways that are intended to be used only by service personnel or employees.

Exception No. 2: The required branch circuit shall be permitted to supply loads directly related to the control of the sign such as electronic or electromechanical controllers.

600.35  Retrofit Kits.

(A)  General.

A general-use or sign-specific retrofit kit for a sign or outline lighting system shall include installation instructions and requirements for field conversion of a host sign. The retrofit kit shall be listed and labeled.

(B)  Installation.

The retrofit kit shall be installed in accordance with the installation instructions.

(1)  Wiring Methods.

Wiring methods shall be in accordance with Chapter 3.

Exception: If powered from a Class 2 source, wiring methods shall be in accordance with 600.12(C)(1)(2) and (C)(2), 600.24, and 600.33.

(3)  Workmanship.

Field conversion workmanship shall be in accordance with 110.12.

(B)  Damaged Parts.

All parts that are not replaced by a retrofit kit shall be inspected for damage. Any part found to be damaged or damaged during conversion of the sign shall be replaced or repaired to maintain the sign or outline lighting system’s dry, damp, or wet location rating.

(C)  Marking.

The retrofitted sign shall be marked in accordance with 600.4(B).

(A)  Traveling Cables.

(1)  Lighting Circuits.

For lighting circuits, 14 AWG copper, 20 AWG copper or larger conductors shall be permitted in parallel, provided the ampacity is equivalent to at least that of 14 AWG copper.

(2)  Class 2 and Communications Circuits.

Communications cables used for Class 2 or communications circuits shall have a current limit equal to or greater than the current required to power the powered Class 2 or communications device. Communications cables shall comply with 800.179. The minimum conductor size for communications circuits shall be 24 AWG.

(A)  Car Light Receptacles, Auxiliary Lighting, and Ventilation.

A separate branch circuit shall supply the car lights. The car lights branch circuit shall be permitted to supply receptacles, accessory equipment (alarm devices, alarm bells, emergency responder radio coverage (ERRC), car ventilation purification systems, monitoring devices not part of the control system), auxiliary lighting power source, car emergency signaling, communications devices (including their associated charging circuits), and ventilation on each elevator car or inside the operation controller. The overcurrent device protecting the branch circuit shall be located in the elevator machine room, control room, machinery space, or control space. Where there is no machine room, control room, machinery space, or control space outside the hoistway, the overcurrent device shall be located outside the hoistway and accessible to qualified persons only.

Required lighting shall not be connected to the load side of a ground-fault circuit interrupter.

620.36  Different Systems in One Raceway or Traveling Cable.

Optical fiber cables and conductors for operating devices, operation and motion control, power, signaling, fire alarm, lighting, heating, and air-conditioning circuits of 1000 volts or less shall be permitted to be run in the same traveling cable or raceway system if all conductors are insulated for the maximum voltage applied to any conductor within the cables or raceway system and if all live parts of the equipment are insulated from ground for this maximum voltage. Traveling cable or raceway shall also be permitted to include shielded pairs, coaxial cables, and other communications circuits shielded conductors and/or one or more coaxial cables if such conductors are insulated for the maximum voltage applied to any conductor within the cable or raceway system. Conductors shall be permitted to be covered with suitable shielding for telephone, audio, video, or higher frequency communications circuits Type CMP-LP or CMR-LP cables complying with 800.179 shall be permitted in raceways.

(A)  Type.

The disconnecting means shall be an enclosed externally operable fused motor circuit switch or circuit breaker that is lockable only in the open position in accordance with 110.25.

The disconnecting means shall be a listed device.

Informational Note No. 1: See ASME A17.1-2019/CSA B44-19, Safety Code for Elevators and Escalators, for additional information.

Informational Note No. 2: See ASME A18.1-2017, Safety Standard for Platform Lifts and Stairway Chairlifts, for additional information.

Exception No. 1: Where an individual branch circuit supplies a platform lift, the disconnecting means required by 620.51(C)(4) shall be permitted to comply with 430.109(C). This disconnecting means shall be listed and shall be lockable open in accordance with 110.25.

Exception No. 2: Where an individual branch circuit supplies a stairway chairlift or where a stairway chairlift is supplied by batteries as the primary source, the stairway chairlift shall be permitted to be cord-and-plug-connected, provided it complies with 422.16(A) and the cord does not exceed 1.8 m (6 ft) in length.

625.6  Listed.

All equipment covered by the scope of this article Electric vehicle power transfer system equipment for the purposes of charging, power export, or bidirectional current flow shall be listed.

(A)  Portable Equipment.

Portable equipment shall be connected to the premises wiring system by one or more of the following methods:

• A nonlocking, 2-pole, 3-wire grounding-type receptacle outlet rated at 125 volts, single phase, 15 or 20 amperes
• A nonlocking, 2-pole, 3-wire grounding-type receptacle outlet rated at 250 volts, single phase, 15 or 20 amperes
• A nonlocking, 2-pole, 3-wire or 3-pole, 4-wire grounding-type receptacle outlet rated at 250 volts, single phase, 30 or 50 amperes, or 125/250 volts, single-phase, 30 or 50 amperes
• A nonlocking, 2-pole, 3-wire grounding-type receptacle outlet rated at 60 volts dc maximum, 15 or 20 amperes

625.49  Island Mode.

EVPE and bidirectional EVSE that incorporate a power export function shall be permitted to be a part of an interconnected power system operating in island mode.

All 125-volt, 15- and 20-ampere receptacles for electrical hand tools or portable lighting equipment, supplied by single-phase branch circuits rated 150 volts or less to ground, installed in work areas where welders are operated shall have ground-fault circuit-interrupter protection for personnel.

646.19 Entrance to and Egress from Working Space.

For equipment over 1.8 m (6 ft) wide or deep, there shall be one entrance to and egress from the required working space not less than 610 mm (24 in.) wide and 2.0 m (6 1⁄2 ft) high at each end of the working space. Doors shall open at least 90 degrees in the direction of egress to the full extent of their designed egress opening and be equipped with listed panic hardware or listed fire exit hardware. A single entrance to and egress from the required working space shall be permitted where either of the conditions in 646.19(A) or (B) is met.

670.1  Scope.

This article covers the definition of, the nameplate data for, overvoltage protection for, and the size and overcurrent protection of supply conductors to industrial machinery.

Informational Note No. 1: See NFPA 79-2021, Electrical Standard for Industrial Machinery, for further information.

Informational Note No. 2: See 110.26 for information on the workspace requirements for equipment containing supply conductor terminals.

Informational Note No. 3: See NFPA 79-2021, Electrical Standard for Industrial Machinery, for information on the workspace requirements for machine power and control equipment.

Article  680  Swimming Pools, Fountains, and Similar Installations
Part I.  General
680.1  Scope.
The provisions of this article apply to the construction and installation of electrical wiring for, and equipment in or adjacent to, all swimming, wading, therapeutic, and decorative pools; fountains; hot tubs; spas; and hydromassage bathtubs, whether permanently installed or storable, and to metallic auxiliary equipment, such as pumps, filters, and similar equipment. The term body of water used throughout Part I applies to all bodies of water covered in this scope unless otherwise amended.

Note: See NEC for Complete Text

680.5  Ground-Fault Circuit-Interrupter Protection (GFCI) and Special Purpose Ground-Fault Circuit-Interrupter (SPGFCI) Protection.

(A)  General.

The GFCI and SPGFCI requirements in this article, unless otherwise noted, are in addition to the requirements in 210.8.

Detail SR-8381

Detail SR-8714

(B)  150 Volts or Less to Ground.

Where required in this article, ground-fault protection of receptacles and outlets on branch circuits rated 150 volts or less to ground and 60 amperes or less, single- or 3-phase, shall be provided with a Class A GFCI.

Exception: Receptacles and outlets that are part of listed equipment with ratings not exceeding the low-voltage contact limit that are supplied by listed transformers or power supplies that comply with 680.23(A)(2) shall not be required to be provided with ground-fault protection.

Informational Note: The high leg of a 120/240-volt 4-wire delta-connected system, and the two ungrounded phases of a corner-grounded delta system have a voltage to ground greater than 150 volts, exceeding the limit for a Class A GFCI.

(C)  Above 150 Volts to Ground.

Where required in this article, ground-fault protection of receptacles and outlets on branch circuits operating at voltages above 150 volts to ground, not exceeding 480 volts phase-to-phase, single- or 3-phase, shall be provided with ground-fault SPGFCI protection not to exceed 20-mA ground-fault trip current.

Informational Note: See UL 943C, Outline of Investigation for Special Purpose Ground-Fault Circuit Interrupters, for information on Classes C, D, and E ground-fault circuit interrupters, which trip when the current to ground is 20 mA or higher and do not trip when the current to ground is less than 15 mA.

(A)  Power.

With respect to overhead Overhead conductors and open overhead wiring, swimming pool and similar installations not in an a shall comply with the minimum clearances given in Table 680.9(A) and illustrated in Figure 680.9(A).

Informational Note: Open overhead wiring as used in this article refers to conductor(s) not in an enclosed raceway.

680.10  Electric Pool Water Heaters Incorporating Resistive Heating Elements and Electrically Powered Swimming Pool Heat Pumps and Chillers.

All electric pool water heaters shall have the heating elements subdivided into loads not exceeding 48 amperes and protected at not over 60 amperes. The ampacity of the branch-circuit conductors and the rating or setting of overcurrent protective devices shall not be less than 125 percent of the total nameplate-rated load.

(A)  Electric Pool Water Heaters.

All electric pool water heaters incorporating resistive heating elements shall have the heating elements subdivided into loads not exceeding 48 amperes and protected at not over 60 amperes. The ampacity of the branch-circuit conductors and the rating or setting of overcurrent protective devices shall not be less than 125 percent of the total nameplate-rated load or greater.

(B)  Electrically Powered Swimming Pool Heat Pumps and Chillers.

Electrically powered swimming pool heat pumps and chillers using the circulating water system and providing heating, cooling, or both, shall be listed and rated for their intended use. The ampacity of the branch-circuit conductors and the rating or setting of overcurrent protective devices shall be sized to comply with the nameplate.

(D)  Pool Pump Motor Replacement.

Where a pool pump motor in 680.21(C) is replaced for maintenance or removed for repair repaired, the replacement or repaired pump motor shall be provided with ground-fault circuit-interrupter protection complying with 680.5(B) or (C), as applicable.

680.12  Equipment Rooms, Vaults, and Pits.
(A)  Drainage.

Electrical equipment shall not be installed in rooms, vaults, or pits that do not have drainage that prevents water accumulation during normal operation or filter maintenance. Equipment shall be suitable for the environment in accordance with 300.6maintenance unless the equipment is rated and identified for submersion.

Informational Note: Chemicals such as chlorine cause severe corrosive and deteriorating effects on electrical connections, equipment, and enclosures when stored and kept in the same vicinity. Adequate ventilation of indoor spaces such as equipment and storage rooms is addressed by ANSI/APSP-11, Standard for Water Quality in Public Pools and Spas, and can reduce the likelihood of the accumulation of corrosive vapors.

(B)  Receptacles.

At least one GFCI-protected 125-volt, 15- or 20-ampere receptacle supplied from a general purpose branch circuit shall be located within an equipment room. All other receptacles supplied by branch circuits rated 150 volts or less to ground within an equipment room and any receptacles supplied by a branch circuit rated 150 volts or less to ground in a vault or pit shall be GFCI protected.

(2)  Wiring Extending Directly to the Forming Shell.

Conduit shall be installed from the forming shell to a junction box or other enclosure conforming to the requirements in 680.24. Conduit shall be rigid metal, intermediate metal, liquidtight flexible nonmetallic, or rigid polyvinyl chloride conduit.

Metal Conduit. Metal conduit shall be listed and identified as shall be red brass or stainless steel.

Informational Note: See UL 6A, Electrical Rigid Metal Conduit – Aluminum, Red Brass, and Stainless Steel, for information on the listing criteria for red brass and stainless steel conduit.

Nonmetallic Conduit. Where a nonmetallic conduit is used, an 8 AWG insulated solid or stranded copper bonding jumper shall be installed in this conduit unless a listed low-voltage lighting system not requiring grounding is used. The bonding jumper shall be terminated in the forming shell, junction box or transformer enclosure, or ground-fault circuit-interrupter enclosure. The termination of the 8 AWG bonding jumper in the forming shell shall be covered with, or encapsulated in, a listed potting compound to protect the connection from the possible deteriorating effect of pool water.

680.32  Ground-Fault Circuit Interrupters Protection Required Circuit-Interrupter (GFCI) and Special Purpose Ground-Fault Circuit-Interrupter (SPGFCI) Protection.

All electrical equipment, including power-supply cords, used with storable pools shall be protected by have  ground-fault GFCI circuit interrupters protection complying with 680.5(B) or SPGFCI protection complying with 680.5(C), as applicable.

All 125-volt, 15- and 20-ampere receptacles rated 125 volts through 250 volts, 60 amperes or less, located within 6.0 m (20 ft) of the inside walls of a storable pool, storable spa, or storable hot tub shall be protected by a have ground-fault circuit interrupter GFCI protection complying with 680.5(B) or SPGFCI protection complying with 680.5(C), as applicable. In determining these dimensions, the distance to be measured shall be the shortest path the supply cord of an appliance connected to the receptacle would follow without piercing a floor, wall, ceiling, doorway with hinged or sliding door, window opening, or other effective permanent barrier.

(A)  Emergency Switch for Spas and Hot Tubs.

A In other than one-family dwellings, a clearly labeled emergency shutoff or control switch for the purpose of stopping the motor(s) that provides power to the recirculation system and jet system shall be installed at a point readily accessible to the users and not less than 1.5 m (5 ft) away, adjacent to, and within sight of the spa or hot tub. This requirement shall not apply to one-family dwellings.

680.44  Ground-Fault Circuit-Interrupter (GFCI) and Special Purpose Ground-Fault Circuit-Interrupter (SPGFCI) Protection.

Except as otherwise provided in this section, the outlet(s) that supplies a self-contained spa or hot tub, a packaged spa or hot tub equipment assembly, or a field-assembled spa or hot tub shall be protected by a ground-fault circuit interrupter.

(A)  General.

Except as otherwise provided in this section, the outlet(s) that supplies a self-contained spa or hot tub, a packaged spa or hot tub equipment assembly, or a field-assembled spa or hot tub shall have GFCI complying with 680.5(B) or (C), or SPGFCI protection complying with 680.5(C)as applicable be protected by a ground-fault circuit interrupter.

(B)  Listed Units.

If so marked, a listed, labeled, and identified self-contained unit or a listed, labeled, and identified packaged equipment assembly that includes integral ground-fault circuit-interrupter GFCI protection for all electrical parts within the unit or assembly (pumps, air blowers, heaters, lights, controls, sanitizer generators, wiring, and so forth) shall be permitted without additional GFCI ground-fault protection.

(C)  Other Units.

A field-assembled spa or hot tub rated 3 phase or rated over 250 volts or with a heater load of more than 50 amperes shall not require the supply to be protected by a ground-fault circuit interrupter.

Informational Note: See 680.2 for definitions of self-contained spa or hot tub and for packaged spa or hot tub equipment assembly.

(C)  Gas-Fired Water Heaters.

Circuits serving gas-fired spa and hot tub water heaters operating separately from the spa or hot tub they serve, and operating at voltages above the low-voltage contact limit, shall be GFCI protected.

(C)  Equipotential Bonding of Splash Pads.

For the purposes of equipotential bonding, the shell of a splash pad shall be comprised of the area traversed by pedestrians bounded by the extents of the footing of the splash pad and rising to its exposed surface(s) and its collection basin area, and the boundary of this area shall be considered to be the inside wall for the purpose of perimeter bonding.

Figure Informational Note Figure 690.1(b) Identification of PV System Components in Common Configurations. Illustration of PV System Components, PV Source Circuit, and dc-to-dc Converter Circuit in a Typical PV Installation.

Figure Informational Note Figure 690.1(c) Illustration of PV Source Circuit and dc Combiner in a Typical PV Installation.

(G)  PV Equipment Floating on Bodies of Water.

PV equipment floating on or attached to structures floating on bodies of water shall be identified as being suitable for the purpose and shall utilize wiring methods that allow for any expected movement of the equipment.

Informational Note: PV equipment in these installations are often subject to increased levels of humidity, corrosion, and mechanical and structural stresses.  Expected movement of floating PV arrays is often included in the structural design.

(D)  Power Transformers.

Overcurrent protection for a transformer with a source(s) on each side shall be provided in accordance with 450.3 by considering first one side of the transformer, then the other side of the transformer, as the primarypower transformers shall be installed in accordance with 705.30(C) 705.30(F).

Exception: A power transformer with a current rating on the side connected toward the interactive inverter output, not less than the rated continuous output current of the inverter, shall be permitted without overcurrent protection from the inverter.

PV system circuits installed on or in buildings shall include a rapid shutdown function to reduce shock hazard for firefighters in accordance with 690.12(A) through (D).

Exception No. 1: Ground-mounted PV system circuits that enter buildings, of which the sole purpose is to house PV system equipment, shall not be required to comply with 690.12.

Exception No. 2: PV equipment and circuits installed on non-enclosed detached structures including but not limited to parking shade structures, carports, solar trellises, and similar structures shall not be required to comply with 690.12.

Informational Note: Exceptions for rapid shutdown are intended to be consistent with building and fire codes that have limitations as to the types of buildings on which firefighters typically perform rooftop operations. 

(2)  Inside the Array Boundary.

The PV system shall comply with one of the following:

A The PV system shall provide shock hazard control system listed for the purpose shall be firefighters through the use of a PVHCS installed in accordance with the instructions included with the listing or field labeling. Where a hazard control system PVHCS requires initiation to transition to a controlled state, the rapid shutdown initiation device required in 690.12(C) shall perform this initiation.

Informational Note: A listed or hazard PV hazard control system PVHCS is comprised of either an individual piece of equipment that fulfills the necessary functions or multiple pieces of equipment coordinated to perform the functions as described in the installation instructions to reduce the risk of electric shock hazard within a damaged PV array for firefighters. See UL 3741, Photovoltaic Hazard Control.

Controlled conductors located inside the boundary shall be limited The PV system shall provide shock hazard control for firefighters by limiting the highest voltage inside equipment or between any two conductors of a circuit or any conductor and ground inside array boundary to not more than 80 volts within 30 seconds of rapid shutdown initiation. Voltage shall be measured between any two conductors and between any conductor and ground.

PV arrays shall have no exposed wiring methods or conductive parts and be installed more than 2.5 m (8 ft) from exposed grounded conductive parts or ground.

Informational Note: Common methods include the use of PV equipment with a limited maximum voltage of 80 volts as determined by 690.7, PVRSE, PVHCE, or any combination of these.

(A)  Type of Disconnecting Means.

Where a disconnects are is required to isolate equipment, the disconnecting means shall be one of the following applicable types:

• An equipment disconnecting means in accordance with 690.15(C)shall be required to isolate dc circuits with a maximum circuit current over 30 amperes.
• An isolating device in accordance with 690.15(B) shall be permitted for circuits other than those covered by 690.15(D)(1).as part of listed equipment where an interlock or similar means
• For circuits with a maximum circuit current of 30 amperes or less, an isolating device in accordance with 690.15(B)

(B)  Identification and Grouping.

PV system dc circuits and Class 1 remote control, signaling, and power-limited circuits of a PV system shall be permitted to occupy the same equipment wiring enclosure, cable, or raceway. PV system dc circuits shall not occupy the same equipment wiring enclosure, cable, or raceway. as other non-PV systems, or inverter output circuits, unless the PV system dc circuits are separated from other circuits by a barrier or partition. PV system circuit conductors shall be identified and grouped as required by 690.31(B)(1) and (B)(2).

Exception: PV system dc circuits utilizing multiconductor jacketed cable or metal-clad cable assemblies or listed wiring harnesses identified for the application shall be permitted to occupy the same wiring method as inverter output circuits and other non-PV systems. All conductors, harnesses, or assemblies shall have an insulation rating equal to at least the maximum circuit voltage applied to any conductor within the enclosure, cable, or raceway.

(1)  Conductors of Different Systems.

Where not otherwise allowed in an equipment’s listing, PV system dc circuits shall not occupy the same equipment wiring enclosure, cable, or raceway. as other non-PV systems, or inverter output circuits, unless the PV system dc circuits are separated from other circuits by a barrier or partition.

Exception: Where all conductors or cables have an insulation rating equal to at least the maximum circuit voltage applied to any conductor within the same wiring method, the following shall be permitted:

• Multiconductor jacketed cables for remote control, signaling, or power-limited circuits shall be permitted within the same wiring enclosure, cable, or raceway as PV system dc circuits where all circuits serve the PV system.
• Inverter output circuits shall be permitted to occupy the same junction box, pull box, or wireway with PV system dc circuits that are identified and grouped as required by 690.31(B)(2) and (B)(3).
• PV system dc circuits utilizing multiconductor jacketed cable or metal-clad cable assemblies or listed wiring harnesses identified for the application shall be permitted to occupy the same wiring method as inverter output circuits and other non-PV systems.

(2)  Identification.

PV system dc circuit conductors shall be identified at all termination, connection, and splice points by color coding, marking tape, tagging, or other approved means in accordance with 690.31(B)(2)(a) and (B)(2)(b). Conductors relying on other than color coding for polarity identification shall be identified by an approved permanent marking means such as labeling, sleeving, or shrink-tubing that is suitable for the conductor size. The permanent marking means for nonsolidly grounded positive conductors shall include imprinted plus signs (+) or the word POSITIVE or POS durably marked on insulation of a color other than green, white, or gray. The permanent marking means for nonsolidly grounded negative conductors shall include imprinted negative signs (−) or the word NEGATIVE or NEG durably marked on insulation of a color other than green, white, gray, or red. Only solidly grounded PV system dc circuit conductors shall be marked in accordance with 200.6.

Exception: Where the identification of the conductors is evident by spacing or arrangement, further identification shall not be required.

1. Conductors relying that rely on other than color coding for polarity identification shall be identified by an approved permanent marking means such as labeling, sleeving, or shrink-tubing that is suitable for the conductor size.
2. The permanent marking means for non-solidly grounded positive conductors shall include imprinted plus signs (+) or the word POSITIVE or POS durably marked on insulation of a color other than green, white, or gray. The permanent marking means for nonsolidly grounded negative conductors shall include imprinted negative signs (−) or the word NEGATIVE or NEG durably marked on insulation of a color other than green, white, gray, or red. Only solidly grounded PV system dc circuit conductors shall be marked in accordance with 200.6.

(3)  Grouping.

Where the ac and dc conductors of more than one PV systems occupy the same junction box, pull box, or raceway with a removable cover(s)wireway, the PV system ac and dc circuit conductors of each system shall be grouped separately by cable ties or similar means at least once and shall then be grouped at intervals not to exceed 1.8 m (6 ft).

Exception: The requirement for grouping shall not apply if the circuit enters from a cable or raceway unique to the circuit that makes the grouping obvious.

(1)  Conductors of Different Systems.

Where not otherwise allowed in an equipment’s listing, PV system dc circuits shall not occupy the same equipment wiring enclosure, cable, or raceway. as other non-PV systems, or inverter output circuits, unless the PV system dc circuits are separated from other circuits by a barrier or partition.

Exception: Where all conductors or cables have an insulation rating equal to at least the maximum circuit voltage applied to any conductor within the same wiring method, the following shall be permitted:

• Multiconductor jacketed cables for remote control, signaling, or power-limited circuits shall be permitted within the same wiring enclosure, cable, or raceway as PV system dc circuits where all circuits serve the PV system.
• Inverter output circuits shall be permitted to occupy the same junction box, pull box, or wireway with PV system dc circuits that are identified and grouped as required by 690.31(B)(2) and (B)(3).
• PV system dc circuits utilizing multiconductor jacketed cable or metal-clad cable assemblies or listed wiring harnesses identified for the application shall be permitted to occupy the same wiring method as inverter output circuits and other non-PV systems.

700.2  Reconditioned Equipment.

Reconditioned transfer switches shall not be permitted.

701.2  Reconditioned Equipment.

Reconditioned transfer switches shall not be permitted.

 702.2  Reconditioned Equipment.

Reconditioned transfer switches shall not be permitted.

708.2  Reconditioned Equipment.

Reconditioned transfer switches shall not be permitted.

(F)  Temporary Source of Power for Maintenance or Repair of the Alternate Source of Power.

If the emergency system relies on a single alternate source of power, which will be disabled for maintenance or repair, the emergency system shall include permanent switching means to connect a portable or temporary alternate source of power, which that shall be available for the duration of the maintenance or repair. The permanent switching means to connect a portable or temporary alternate source of power shall comply with the following:

• Connection to the portable or temporary alternate source of power shall not require modification of the permanent system wiring.
• Transfer of power between the normal power source and the emergency power source shall be in accordance with 700.12.
• The connection point for the portable or temporary alternate source shall be marked with the phase rotation and system bonding requirements.
• Mechanical or electrical interlocking shall The switching means, including the interlocks, shall be listed and provided with mechanical or mechanical and electrical interlocking to prevent inadvertent interconnection of power sources.
• The switching means shall include a contact point that shall annunciate at a location remote from the generator or at another facility monitoring system to indicate that the permanent emergency source is disconnected from the emergency system.
• The permanent connection point for the temporary generator shall be located outdoors and shall not have cables from the connection point to the temporary generator routed through exterior windows, doors, or similar openings.
• A permanent label shall be field applied at the permanent connection point to identify the system voltage, maximum amperage, short-circuit current rating of the load side of equipment supplied, and ungrounded conductor identification in accordance with 210.5.

(D)  Redundant Transfer Equipment.

If emergency loads are supplied by a single feeder, the emergency power system shall include redundant transfer equipment or a bypass isolation transfer switch to facilitate maintenance as required in 700.3(C) without jeopardizing continuity of power. If the redundant transfer equipment or bypass isolation transfer switch is manual (or nonautomatic), then it shall be actively supervised by a qualified person when the primary (automatic) transfer equipment is disabled for maintenance or repair.

Exception: The requirement for a bypass isolation redundancy with the transfer switch equipment shall not apply where any of the following conditions exists:

• All processes that rely on the emergency system source are capable of being disabled during maintenance or repair activities without jeopardizing the safety to human life.
• The building or structure is unoccupied and fire protection systems are fully functional and do not require an alternate power source.
• Other temporary means shall be permitted to be substituted for the emergency system.
• A written emergency plan that includes mitigation actions and responsibilities for qualified persons to address the recognized site hazards for the duration of the maintenance or repair activities shall be developed and implemented. The emergency plan shall be made available to the authority having jurisdiction.

(C)  Separation of Circuits.

Class 2 emergency circuits shall be wired in a listed, jacketed cable or with one of the wiring methods of Chapter 3. If installed alongside nonemergency Class 2 circuits that are bundled, Class 2 emergency circuits shall be bundled separately. If installed alongside nonemergency Class 2 circuits that are not bundled, Class 2 emergency circuits shall be separated by a nonconductive sleeve or nonconductive barrier from all other Class 2 circuits. Class 2 emergency circuits shall be separated from nonemergency Class 2 circuits. Separation from other circuits shall comply with 725.136.

(C)  Storage Battery Supply Duration.

Storage batteries shall be of suitable rating and capacity to supply and maintain the total load for a minimum period of 11⁄2 hours, without the voltage applied to the load falling below 871⁄2 percent of normal. Automotive-type batteries shall not be used The emergency power source shall be of suitable rating and capacity to supply and maintain the total load for the duration determined by the system design. In no case shall the duration be less than 2 hours of system operation unless used for emergency illumination in 700.12(C)(4) or unit equipment in 700.12(I). Additionally, the power source shall comply with 700.12(C)(1) through (C)(5) as applicable.

An automatic battery charging means shall be provided.

Informational Note: See NFPA 110-2022, Standard for Emergency and Standby Power Systems, for information on classification of emergency power supply systems (EPSS).

(1)  On-Site Fuel Supply.

Where internal combustion engines are used as the prime mover, an An on-site fuel supply shall be provided, with an on-premises fuel supply sufficient for not less than 2 hours’ operation of the system.

(2)  Fuel Transfer Pumps.

Where power is needed for the operation of the fuel transfer pumps to deliver fuel to a generator set day tank, this pump the source, these pumps shall be connected to the emergency power system.

(3)  Public Gas System, Municipal Water Supply.

Prime movers Sources shall not be solely dependent on a public utility gas system for their fuel supply or municipal water supply for their cooling systems.

Exception: Where approved by the authority having jurisdiction, the use of other than on-site fuels shall be permitted where there is a low probability of a simultaneous failure of both the off-site fuel delivery system and power from the outside electrical utility company. Where the public gas system is approved, the requirements of 700.12(C)(1) shall not apply.

(4)  Storage Batteries and UPS.

Storage batteries and uninterruptable power supply systems used to supply emergency illumination shall be of suitable rating and capacity to supply and maintain the total load for a minimum period of 11⁄2 hours, without the voltage applied to the load falling below 871⁄2 percent of normal nominal voltage. Automotive-type batteries shall not be used. An automatic battery charging means shall be provided.

(5)  Automatic Fuel Transfer

Where dual fuel supplies sources are used, means shall be provided for automatically transferring from one fuel supply source to another.

(E)  Uninterruptible Power Supplies Stored-Energy Power Supply Systems (SEPSS).

Uninterruptible power supplies used to provide power for emergency systems shall comply with the applicable provisions of 700.12(B) and (C)Stored energy power supply systems shall comply with 700.12(E)(1) and (E)(2).

(1)  Types.

Systems shall consist of one or more of the following system types:

• Uninterruptible power supply (UPS)
  1. Informational Note: See UL 1778, Uninterruptible Power Systems, for further information.
• Fuel cell system
• Energy storage system (ESS)
• Storage battery
• Other approved equivalent stored energy sources that comply with 700.12

(2)  Fire Protection, Suppression, Ventilation, and Separation.

The systems in 700.12(E)(1) shall be installed with the fire protection, suppression, ventilation, and separation requirements specified in the manufacturer’s instructions or equipment listing.

Informational Note: See NFPA 853-2020, Standard for the Installation of Stationary Fuel Cell Power Systems, and NFPA 855-2020, Standard for the Installation of Stationary Energy Storage Systems, for additional information on fire protection installation

(G)  DC Microgrid Systems.

Sources connected to a dc microgrid system shall be permitted where the system is capable of being isolated from all non-emergency sources On-site sources, designated as emergency sources, shall be permitted to be connected to a microgrid system.

DC microgrid systems used as a source of power for emergency systems shall be of suitable rating and capacity to supply and maintain the total emergency load for not less than 2 hours of full-demand operation The system shall isolate the emergency system from all nonemergency loads when the normal electric supply is interrupted or shall meet the requirements of 700.4(C). Interruption or partial or complete failure of the normal or nonemergency source(s) shall not impact the availability, capacity, and duration provided by the designated emergency sources.

Where a dc microgrid system source serves as the normal supply for the building or group of buildings concerned, it shall not serve as the sole source of power for the emergency standby system The designated stored-energy electrical emergency power source(s) of a microgrid system shall be permitted to remain interconnected to any available power production source during operation of the emergency source(s) where the lack of, or failure of, the interconnected power production source(s), or related controls, does not impact system operation. Interconnected power production sources, other than the designated stored emergency power source(s), shall not be required to meet the requirements of Article 700.

(C)  Load Pickup and Load Shedding Management.

The alternate power source shall be permitted to supply legally required standby and optional standby system loads where the alternate source has adequate capacity or where load management (that includes automatic selective load pickup and load shedding are provided )is provided that will ensure adequate power to the legally required standby circuits.

(D)  Parallel Operation.

Parallel operation shall comply with Part I or Part II of Article 705 where the legally required source capacity required to supply the legally required load is maintained at all times. Parallel operation of the legally required source(s) shall consist of the sources specified in 701.4(D)(1) and (D)(2).

(1)  Normal Source.

The alternate power source shall be permitted to operate in parallel with the normal source in compliance with Part I or Part II of Article 705 where the capacity required to supply the legally required standby load is maintained at all times. Any operating condition that results in less than the required source capacity shall initiate a legally required standby source malfunction signal in 701.6(A).

Parallel operation shall be permitted for satisfying the test requirements of 701.3(B), provided all other conditions of 701.3 are met.

Informational Note: Peak load shaving is one application for parallel source operation.

(2)  Alternate Source.

Legally required standby sources shall be permitted to operate in parallel where the necessary equipment to establish and maintain a synchronous condition is provided.

701.10  Wiring Legally Required Standby Systems.

The legally required standby system wiring shall be permitted to occupy the same raceways, cables, boxes, and cabinets with other general wiring.

(A)  General.

The legally required standby system wiring shall be permitted to occupy the same raceways, cables, boxes, and cabinets with other general wiring.

(B)  Wiring.

Wiring from a legally required source to supply legally required and other (non-legally required) loads shall be in accordance with the following:

• The common bus of switchgear, sections of a switchboard, or individual enclosures shall be either of the following:
  1. Supplied by single or multiple feeders without overcurrent protection at the source
  2. Supplied by single or multiple feeders with overcurrent protection, provided that the overcurrent protection that is common to a legally required system and any non-legally required system(s) is selectively coordinated with the next downstream overcurrent protective device in the non-legally required system(s)

Informational Note: See Informational Note Figure 701.10(B)(a) and Informational Note Figure 701.10(B)(b) for further information.

(C)  Storage Battery Supply Duration.

The alternate power source shall be of suitable rating and capacity to supply and maintain the total load for the duration determined by the system design. In no case shall the duration be less than 2 hours of system operation. Additionally, the power source shall comply with 701.12(C)(1) through (C)(5) as applicable.

Informational Note: See NFPA 110-2022, Standard for Emergency and Standby Power Systems, for information on classification of emergency power supply systems (EPSS).

705.11  Source Connections to a Service.

 Note: See NEC for Complete Text

705.13  Power Control Energy Management Systems (EMS).

A power control system (PCS) shall be listed and evaluated to control the output of one or more power production sources, energy storage systems (ESS), energy management systems, and other equipment. The PCS shall limit current and loading on the busbars and conductors supplied by the PCS An EMS in accordance with 750.30 shall be permitted to limit current and loading on the busbars and conductors supplied by the output of one or more interconnected electric power production or energy storage sources.

Informational Note: A listed power control system (PCS) is a type of EMS that is capable of monitoring multiple power sources and controlling the current on busbars and conductors to prevent overloading. See UL 1741, Inverters, Converters, Controllers and Interconnection System Equipment for Use with Distributed Energy Resources, and UL 916, Energy Management Equipment, for information on PCS and EMS.

For the circuits connected to a PCS, the PCS shall limit the current to the ampacity of the conductors or the ampere ratings of the busbars to which it is connected in accordance with 705.13(A) through (E).

705.20  Source Disconnecting Means.

Means shall be provided to disconnect power source output circuit conductors of electric power production equipment from conductors of other systems. Specific source disconnecting means required elsewhere in this Code that comply with 705.20 shall be permitted to meet this requirement. A single disconnecting means in accordance with 705.20 shall be permitted to disconnect multiple power sources from conductors of other systems.

Informational Note: See 480.7, Part II of Article 445, Part II,III of Article 690, Part III,of Article 692, Part III,of Article 694, and Part IIIII of and Article 706Part II for specific source disconnecting means requirements.

The disconnecting means shall comply with the following:

• Be one of the following types:
  1. A manually operable switch or circuit breaker
  2. A load-break-rated pull-out switch
  3. A power-operated or remote-controlled switch or circuit breaker that is manually operable locally and opens automatically when control power is interrupted
  4. A device listed or approved for the intended application
• Simultaneously disconnect all ungrounded conductors of the circuit
• Located where readily accessible
• Externally operable without exposed live parts
• Enclosures with doors or hinged covers containing exposed energized parts when the door or cover is open that require a tool to open or are locked where readily accessible to unqualified persons
• Plainly indicate whether in the open (off) or closed (on) position
• Have ratings sufficient for the maximum circuit current, available fault current, and voltage that is available at the terminals
• Where the line and load terminals are capable of being energized in the open position, be marked with the following words or equivalent:

(F)  Power Transformers.

Transformers with sources on each side shall be provided with overcurrent protection in accordance with 450.3. The primary shall be the side connected to the largest source of available fault current. Secondary protection shall not be required for a transformer secondary that has a current rating not less than the sum of the rated continuous output currents of the power sources connected to that secondary.

The following apply to the installation of transformers:

• For the purpose of overcurrent protection, the primary side of transformers with sources on each side shall be provided with overcurrent protection in accordance with 450.3. The primary shall be the side connected to the largest source of available fault current.
• Transformer secondary conductors shall be protected in accordance with 240.21(C).

705.50 System Operation.

Microgrid Interconnected microgrid systems shall be permitted to disconnect from capable of operating in interactive mode with a primary source of power or electric utility or other interconnected electric power production and distribution network. Microgrid systems shall be permitted to disconnect from other sources and operate as an isolated microgrid system operating in island mode.

Informational Note: Microgrid systems often include a single source or a compatible interconnection of multiple sources such as engine generators, solar PV, wind, or ESS.

Informational Note No. 2: See Article 517 for health care facilities incorporating microgrids. 

706.7  Commissioning and Maintenance.

Energy storage systems shall be maintained in proper and safe operating condition. The required maintenance shall be in accordance with the manufacturer’s requirements and industry standards. A written record of the system maintenance shall be kept and shall include records of repairs and replacements necessary to maintain the system in proper and safe operating condition.

Informational Note: For information related to general electrical equipment maintenance and developing an effective electrical preventive maintenance (EPM) program, see NFPA 70B-2019, Recommended Practice for Electrical Equipment Maintenance, or ANSI/NETA ATS-2017, Standard for Acceptance Testing Specifications for Electrical Power Equipment and Systems.

(A)  Commissioning.

ESSs shall be commissioned upon installation. This shall not apply in one- and two-family dwellings.

Informational Note: See NFPA 855-2020, Standard for the Installation of Stationary Energy Storage Systems, for information related to the commissioning of ESSs.

(B)  Maintenance.

Energy storage systems ESSs shall be maintained in proper and safe operating condition. The required maintenance shall be in accordance with the manufacturer’s requirements and industry standards. A written record of the system maintenance shall be kept and shall include records of repairs and replacements necessary to maintain the system in proper and safe operating condition. This shall not apply in one- and two-family dwellings.

Informational Note: For See NFPA 70B-2019, Recommended Practice for Electrical Equipment Maintenance, or ANSI/NETA ATS-2017, Standard for Acceptance Testing Specifications for Electrical Power Equipment and Systems, for information related to general electrical equipment maintenance and developing an effective electrical preventive maintenance (EPM) program, see NFPA 70B-2019, Recommended Practice for Electrical Equipment Maintenance, or ANSI/NETA ATS-2017, Standard for Acceptance Testing Specifications for Electrical Power Equipment and Systems.

Article  722  Cables for Power-Limited Circuits, Fault-Managed Power (Class 4) Circuits, and Optical Fiber

722.1  Scope.

This article covers the general requirements for the installation of single- and multiple-conductor cables used in Class 2 and Class 3 power-limited circuits, power-limited fire alarm (PLFA) circuits, Class 4 fault-managed power circuits, and optical fiber installations.

 Note: See NEC for Complete Text

725.144  Transmission of Bundling of 4 Cables Transmitting Power and Data.

Sections 725.144(A) and (B) shall apply to Class 2 and Class 3 circuits that transmit power and data to a powered device over listed cabling. Section 300.11 and Parts I and III of Article 725 shall apply to Class 2 and Class 3 circuits that transmit power and data. The conductors that carry power for the data circuits shall be copper. The current in the power circuit shall not exceed the current limitation of the connectors.

(A)  Use of 4-Pair Class 2 or Class 3 Cables to Transmit Power and Data.

Where Types Type CL3P, Type CL2P, Type CL3R, Type CL2R, Type CL3, or Type CL2 4-pair cables transmit power and data, the rated current per conductor of the power source shall not exceed the ampacities in Table 725.144 at an ambient temperature of 30°C (86°F). For ambient temperatures above 30°C (86°F), the correction factors in Table 310.15(B)(1)(1) or in Equation 310.15(B) shall apply.

(B)  Use of Class 2-LP or Class 3-LP Cables to Transmit Power and Data.

Types Type CL3P-LP, Type CL2P-LP, Type CL3R-LP, Type CL2R-LP, Type CL3-LP, or Type CL2-LP cables shall be permitted to supply power to equipment from a power source with a rated current per conductor up to the marked current limit located immediately following the suffix “-LP” and shall be permitted to transmit data to the equipment. Where the number of bundled LP cables is 192 or less and the selected ampacity of the cables in accordance with Table 725.144 exceeds the marked current limit of the cable, the ampacity determined from the table shall be permitted to be used. For ambient temperatures above 30°C (86°F), the correction factors of Table 310.15(B)(1)(1) or Equation 310.15(B) shall apply. The Class 2-LP and Class 3-LP cables shall comply with the following, as applicable:

Article 726 Class 4 Fault-Managed Power Systems.

726.1  Scope.

This article covers the installation of wiring and equipment of fault-managed power (FMP) systems inoccupancies other than dwelling units, including utilization equipment incorporating parts of these systems.

Note: See NEC for Complete Text

Article 760 Fire Alarm Systems

760.1  Scope.

This article covers the installation of wiring and equipment of fire alarm systems, including all circuits controlled and powered by the fire alarm system.

 Note: See NEC for Complete Text

800.179  Plenum, Riser, General-Purpose, and Limited Use Wires and Cables.

Plenum, riser, general-purpose, and limited-use Communications wires and cables, community antenna television cables, and network-powered broadband communications cables shall be listed in accordance with 800.179(A) through (D) (I) and shall have a temperature rating of not less than 60°C (140°F). The temperature rating shall be marked on the jacket of cables that have a temperature rating exceeding 60°C (140°F). The cable voltage rating shall not be marked on the cable. Conductors in communications cables, other than in a coaxial cable, shall be copper. Cables shall be permitted to contain optical fibers. Cables containing optical fibers shall be marked with the suffix “-OF.”

Communications wires and cables and network-powered communications cables shall have a voltage rating of not less than 300 volts. The insulation for the individual conductors, other than the outer conductor of a coaxial cable, shall be rated for 300 volts minimum. The cable voltage rating shall not be marked on the cable or on the under-carpet communications wire.

Note: See NEC for Complete Text

805.170  Equipment Protectors.

Communications equipment shall be listed as being suitable for electrical connection to a communications network Protectors shall be listed in accordance with 805.170(A) or 805.170(B).

Informational Note No. 1: See ANSI/UL 60950-1-2014, Standard for Safety of Information Technology Equipment, ANSI/UL 1863-2012, Standard for Safety Communications Circuit Accessories, or ANSI/UL 62368-1-2014 or ANSI/UL 62368-1-2018, Audio/Video, Information and Communication Technology Equipment — Part 1: Safety Requirements.

Informational Note No. 2: See ANSI/ATIS 0600337-2016, Requirements for Maximum Voltage, Current, and Power Levels Used in Communications Circuits, for additional information regarding voltages, currents, and power allowed on communications circuits.

(A)  Primary Protectors.

The primary protector shall be listed and consist of an arrester connected between each line conductor and ground in an appropriate mounting. Primary protector terminals shall be marked to indicate line and ground as applicable.

Informational Note: See ANSI/UL 497-2017, Standard for Protectors for Paired Conductor Communications Circuits, to determine applicable requirements for a listed primary protector.

(B)  Secondary Protectors.

The secondary protector shall be listed as suitable to provide means to safely limit currents to less than the current-carrying capacity of listed indoor communications wire and cable, listed telephone set line cords, and listed communications terminal equipment having ports for external wire line communications circuits. Any overvoltage protection, arresters, or grounding connection shall be connected on the equipment terminals side of the secondary protector current-limiting means.

Informational Note: See ANSI/UL 497A-2019, Standard for Secondary Protectors for Communications Circuits, to determine applicable requirements for a listed secondary protector.

840.160  Powering Circuits.

Communications cables listed in accordance with 805.179Listed communications cables, in addition to carrying the communications circuit, shall also be permitted to carry circuits for powering listed communications equipment listed in accordance with 805.170. The power source shall be listed in accordance with 840.170(C). Installation of the listed 4-pair communications cables for a communications circuit or installation where 4-pair communications cables are substituted for Class 2 and Class 3 cables in accordance with 725.154(A)722.122(E) shall comply with 725.144.

Exception: Installing communications cables in compliance with 725.144 shall not be required for listed 4-pair communications cables where the rated current of the power source does not exceed 0.3 amperes in any conductor 24 AWG or larger.

Informational Note No. 1: A typical communications cable for this application is a 4-pair cable sometimes referred to as Category 5e (or higher) LAN cable or balanced twisted pair cable. These types of cables are often used to provide Ethernet- and Power over Ethernet (PoE)-type services.

Informational Note No. 2: See 725.144 for requirements to manage the temperature rise of bundles of cables that provide power.

Table 13 Equipment Suitable for Hazardous (Classified) Locations

 Note: See NEC for Complete Text

Informative Annex  A  Product Safety Standards

Informative Annex A is not a part of the requirements of this NFPA document but is included for informational purposes only.

This informative annex provides a list of product safety standards used for product listing where that listing is required by this Code. It is recognized that this list is current at the time of publication but that new standards or modifications to existing standards can occur at any time while this edition of the Code is in effect.

This informative annex does not form a mandatory part of the requirements of this Code but is intended to identify for the Code users the standards upon which Code requirements have been based.

Note: See NEC for Complete Text

Informative Annex  E  Types of Construction

This informative annex is not a part of the requirements of this NFPA document but is included for informational purposes only.

Note: See NEC for Complete Text