2023 NEC Significant Code Changes Part 1 Help

90.5(C) Explanatory Material. (Mandatory Rules, Permissive Rules, Explanatory Material)
(C)Explanatory Material.

Explanatory material, such as references to other standards, references to related sections of this Code, or information related to a Code rule, is included in this Code in the form of informational notes or an informative annex. Unless the standard reference includes a date, the reference is to be considered as the latest edition of the standard. Such notes are informational only and are not enforceable as requirements of this Code.

Brackets containing section references to another NFPA document are for informational purposes only and are provided as a guide to indicate the source of the extracted text. These bracketed references immediately follow the extracted text.

Capable of being removed or exposed without damaging the building structure or finish or not permanently closed in or blocked by the structure, other electrical equipment, other building systems, or finish of the building.

Class 4 Circuit. The portion of the wiring system between the load side of a Class 4 transmitter and the Class 4 receiver, or Class 4 utilization equipment, as appropriate. Due to the active monitoring and control of the power transmitted, a Class 4 circuit is not considered a possible ignition source, and it minimizes the risk of electric shock.

Class 4 Device.  Any active device connected to the Class 4 circuit. Some examples of Class 4 devices can include a Class 4 power transmitter, a Class 4 power receiver, or Class 4 utilization equipment.

Class 4 Power System. An actively monitored and controlled system that consists of one or more Class 4 power transmitters and one or more Class 4 power receivers connected by a cabling system.

Class 4 Receiver. A device that accepts Class 4 power and converts the Class 4 power to be used by utilization equipment.

Class 4 Transmitter. A device that sources Class 4 power, monitors the line for faults, ceases power transmission if a fault is sensed, and limits the energy and power into a fault to the levels described in 726.121(A).

Class 4 Tray Cable (CL4TC). A factory assembly of two or more

insulated conductors rated at 450 volts DC, with or without associated bare or insulated equipment grounding conductors, under a nonmetallic jacket. 

 Class 4 Utilization Equipment. Devices that are directly powered by a Class 4 transmitter without the need for a separate Class 4 receiver.

Counter (Countertop).

A fixed or stationary surface typically intended for food preparation and serving, personal lavation, or laundering or a similar surface that presents a routine risk of spillage of larger quantities of liquids upon outlets mounted directly on or in the surface. 

Energy Management System (EMS).

A system consisting of any of the following: a monitor(s), communications equipment, a controller(s), a timer(s), or other device(s) that monitors and/or controls an electrical load or a power production or storage source.

Feeder Assembly.

The overhead or under-chassis feeder conductors, including the equipment grounding conductor, together with the necessary fittings and equipment; or at the power-supply cord listed assembly for a mobile home use, recreational vehicle, or park trailer, identified for the delivery of energy from the source of electrical supply to the panelboard within the mobile home, recreational vehicle, or park trailer

Fibers/Flyings, Combustible. (Combustible Fibers/Flyings)

Fibers/flyings, where any dimension is greater than 500 μm in nominal size, which can form an explosible mixture when suspended in air at standard atmospheric pressure and temperature.

Informational Note No. 1: This definition and Informational Notes No. 2 and No. 3 have been extracted from NFPA 499-2021, Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas. The NFPA 499 reference is in brackets. Only editorial changes were made to the extracted text to make it consistent with this Code.

Informational Note No. 2: Section 500.5(D) defines a Class III location. Combustible fibers/flyings can be similar in physical form to ignitable fibers/flyings and protected using the same electrical equipment installation methods. Examples of fibers/flyings include flat platelet-shaped particulate, such as metal flake, and fibrous particulate, such as particle board core material. If the smallest dimension of a combustible material is greater than 500 μm, it is unlikely that the material would be combustible fibers/flyings, as determined by test. Finely divided solids with lengths that are large compared to their diameter or thickness usually do not pass through a 500 μm sieve, yet when tested could potentially be determined to be explosible.

Informational Note No. 3: See ASTM E1226, Standard Test Method for Explosibility of Dust Clouds, ISO 6184-1, Explosion protection systems — Part 1: Determination of explosion indices of combustible dusts in air, or ISO/IEC/UL 80079-20-2, Explosive atmospheres — Part 20-2: Material characteristics — Combustible dusts test methods, for procedures for determining the explosibility of dusts. A material that is found to not present an explosible mixture could still be an ignitable fiber/flying, as defined in this article. Historically, the explosibility condition has been described as presenting a flash fire or explosion hazard. It could be understood that the potential hazard due to the formation of an explosible mixture when suspended in air at standard atmospheric pressure and temperature would include ignition.

Ground Fault Condition.

An unintentional, electrically conductive connection between an ungrounded conductor of an electrical circuit and the normally non-current-carrying conductors, metallicmetal enclosures, metallicmetal raceways, metallicmetal equipment, or earth.

Grounded System, Impedance (Impedance Grounded System). 

An electrical system that is grounded by intentionally connecting the system neutral point to ground through an impedance device.

Grounded System, Impedance (Impedance Grounded System). 

An electrical system that is grounded by intentionally connecting the system neutral point to ground through an impedance device.

In Sight From (Within Sight From,) (Within Sight).

Where this Code specifies that one equipment shall be “in sight from,” “within sight from,” or “within sight of,” and so forth, another equipment, the specified equipment is to be Equipment that is visible and not more than 15 m (50 ft) distant from the other equipment is in sight from that other equipment.

Likely to Become Energized. 

Conductive material that could become energized because of electrical insulation or electrical spacing failure.

Load Management.

The process within an energy management system that limits the total electrical load on an electrical supply system to a set value by adjusting or controlling the individual loads.

Normal High-Water Level (as applies to electrical datum plane distances).

Natural or Artificially Made Shorelines: An elevation delineating the highest water level that has been maintained for a sufficient period of time to leave evidence upon the landscape, commonly the point where the natural vegetation changes from predominantly aquatic to predominantly terrestrial.

Rivers and Streams: The elevation of the top of the bank of the channel. Streams, rivers, and tributaries that are prone to flooding and effects of water runoff shall consider the “bankfull stage” where an established gauge height at a given location along a river or stream, above which a rise in water surface will cause the river or stream to overflow the lowest natural stream bank somewhere in the corresponding reach.

Flood Control Bodies of Water: The flood pool maximum water surface elevation of a reservoir, equal to the elevation of the spillway.

Non flood Control Bodies of Water: The flowage easement boundary in which the highest water surface elevation defined by the area existing between governmental-owned property line(s) and a contour line with perpetual rights to flood the area in connection with the operation of the reservoir.

PV DC Circuit, Source Circuit. (PV Source Circuit)

The PV dc circuit conductors between modules in a PV string circuit, and from modules string circuits  to dc combiners, electronic power converters, or a dc PV system disconnecting means.

PV DC Circuit, String. (PV String Circuit)

The PV source circuit conductors of one or more series-connected PV modules.

PV DC Circuit (PV System DC Circuit ).

Any dc conductor in PV source circuits, PV output string circuits, dc-to-dc converter source circuits, and PV dc-to-dc converter output circuits.

Restricted Industrial Establishment [as applied to hazardous (classified) locations].

Establishment with restricted public access, where the conditions of maintenance and supervision ensure that only qualified persons service the installation.

Servicing.

The process of following a manufacturer’s set of instructions or applicable industry standards to analyze, adjust, or perform prescribed actions upon equipment with the intention to preserve or restore the operational performance of the equipment.

Short Circuit.

An abnormal connection (including an arc) of relatively low impedance, whether made accidentally or intentionally, between two or more points of different potential.

Transformer.

An individual transformer, Equipment, either single-phase or polyphase, identified by a single nameplate, unless otherwise indicated in this article that uses electromagnetic induction to convert current and voltage in a primary circuit into current and voltage in a secondary circuit.

Work Surface.

A fixed, stationary, or portable surface typically intended for dry use and for tasks other than food preparation, personal lavation, or laundering that presents an incidental risk of spillage of smaller quantities of beverages and other liquids upon outlets mounted directly on or recessed in the surface. (CMP-2)

Informational Note No. 1: See UL 111, Outline of Investigation for Multioutlet Assemblies, and UL 962A, Furniture Power Distribution Units, which establish the performance evaluation criteria and construction criteria.

Informational Note No. 2: See 406.5(F), 406.5(G)(1), and 406.5(H) for information on receptacles for work surfaces distinguished from receptacles for counters and countertops.

110.3 Examination, Identification, Installation, Use, and Listing (Product Certification) of Equipment.

 (A) Examination

(8) Cybersecurity for network-connected life safety equipment to address its ability to withstand unauthorized updates and malicious attacks while continuing to perform its intended safety functionality

 Informational Note No. 3: See the IEC 62443 series of standards for industrial automation and control systems, the UL 2900 series of standards for software cybersecurity for network-connectable products, and UL 5500, Standard for Remote Software Updates, which are standards that provide frameworks to mitigate current and future security cybersecurity vulnerabilities and address software integrity in systems of electrical equipment.

110.3 Examination, Identification, Installation, Use, and Listing (Product Certification) of Equipment.

(B)  Installation and Use.

Equipment that is listed, labeled, or both, or identified for a use shall be installed and used in accordance with any instructions included in the listing or, labeling, or identification.

Informational Note: The installation and use instructions may be provided in the form of printed material, quick response (QR) code, or the address on the internet where users can download the required instructions.

(A)  Terminals.

Connection of conductors to terminal parts shall ensure a thoroughly good mechanically electrical secure connection without damaging the conductors and shall be made by means of pressure connectors (including set-screw type), solder lugs, or splices to flexible leads. Terminal connections shall not be made to the drive surfaces of either wire-binding screws or set-screw-type pressure connectors. Terminal connections shall not rely solely upon friction, magnetic, or cantilevered-spring contact with wire-binding screws or set-screw-type pressure connectors. Connection by means of wire-binding screws or studs and nuts that have upturned lugs or the equivalent shall be permitted for 10 AWG or smaller conductors.

Terminals for more than one conductor and terminals used to connect aluminum shall be so identified.

(B)  Service Equipment and Feeder Supplied Equipment.

In other than dwelling units, in addition to the requirements in 110.16(A), a permanent arc flash label shall be field or factory applied to service equipment and feeder supplied equipment rated 1200 amps1000 amperes or more. The arc flash label shall be in accordance with applicable industry practice and include the date the label was applied. The label shall meet the requirements of 110.21(B) and contain the following information:.

1. Nominal system voltage
2. Available fault current at the service overcurrent protective devices
3. The clearing time of service overcurrent protective devices based on the available fault current at the service equipment
4. The date the label was applied

Exception: Service equipment labeling shall not be required if an arc flash label is applied in accordance with acceptable industry practice.

Informational Note No. 1: NFPA 70E-2018, Standard for Electrical Safety in the Workplace, provides guidance, such as determining severity of potential exposure, planning safe work practices, arc flash labeling, and selecting personal protective equipment.

Informational Note No. 1: See ANSI Z535.4-2011 (R2017), Product Safety Signs and Labels, provides for guidelines for the design of safety signs and labels for application to products.

Informational Note No. 2: See NFPA 70E-2021, Standard for Electrical Safety in the Workplace, Acceptable for applicable industry practices for equipment labeling are described in NFPA 70E-2018, Standard for Electrical Safety in the Workplace. This standard provides specific criteria for developing arc-flash labels for equipment that provides nominal system voltage, incident energy levels, arc-flash boundaries, minimum required levels of personal protective equipment, and so forth.

110.17 Servicing and Maintenance of Equipment.

Servicing and electrical preventive maintenance shall be performed by qualified persons trained in servicing and maintenance of equipment and shall comply with the following:

1. The servicing and electrical preventive maintenance shall be performed in accordance with the original equipment manufacturer’s instructions and information included in the listing information, applicable industry standards, or as approved by the authority having jurisdiction.
2. The servicing and electrical preventive maintenance shall be performed using identified replacement parts that are verified under applicable product standards. The replacement parts shall comply with at least one of the following:
   1. Be provided by the original equipment manufacturer
   2. Be designed by an engineer experienced in the design of replacement parts for the type of equipment being serviced or maintained
   3. Be approved by the authority having jurisdiction

Informational Note No. 1: For equipment that is not listed or field labeled, or for which components are no longer available from the original equipment manufacturer, one way to determine suitability is to review the documentation that accompanies the replacement parts.

Informational Note No. 2: See NFPA 70B, Recommended Practice for Electrical Equipment Maintenance, for information related to preventive maintenance for electrical, electronic, and communication systems and equipment.

110.20 Reconditioned Equipment.

Reconditioned equipment shall be permitted except where prohibited elsewhere in this Code. Equipment that is restored to operating condition shall be reconditioned with identified replacement parts, verified under applicable standards, that are either provided by the original equipment manufacturer or that are designed by an engineer experienced in the design of replacement parts for the type of equipment being reconditioned.

(A)  Equipment Required to Be Listed.

Equipment that is reconditioned and required by this Code to be listed shall be listed or field labeled as reconditioned using available instructions from the original equipment manufacturer.

(B)  Equipment Not Required to Be Listed.

Equipment that is reconditioned and not required by this Code to be listed shall comply with one of the following:

• Be listed or field labeled as reconditioned
• Have the reconditioning performed in accordance with the original equipment manufacturer instructions

(C)  Approved Equipment.

If the options specified in 110.20(A) or (B) are not available, the authority having jurisdiction shall be permitted to approve reconditioned equipment, and the reconditioner shall provide the authority having jurisdiction with documentation of the changes to the product.

(1)  General.

The manufacturer’s name, trademark, or other descriptive marking by which the organization responsible for the product can be identified shall be placed on applied or affixed onto all electrical equipment. Other markings that indicate voltage, current, wattage, or other ratings shall be provided as specified elsewhere in this Code. The marking or label shall be of sufficient durability to withstand the environment involved.

(2)  Reconditioned Equipment.

Reconditioned equipment shall be marked with the name, trademark, or other descriptive marking by which the organization responsible for reconditioning the electrical equipment can be identified, along with the date of the reconditioning. following:

1. Name, trademark, or other descriptive marking of the organization that performed the reconditioning
2. The date of the reconditioning
3. The term reconditioned or other approved wording or symbol indicating that the equipment has been reconditioned

Reconditioned equipment shall be identified as “reconditioned” and the original listing mark removed. The original listing mark shall be removed or made permanently illegible. The equipment nameplate shall not be required to be removed or made permanently illegible, only the part of the nameplate that includes the listing mark, if applicable. Approval of the reconditioned equipment shall not be based solely on the equipment’s original listing.

Exception: In industrial occupancies, where conditions of maintenance and supervision ensure that only qualified persons service the equipment, the markings indicated in 110.21(A)(2) shall not be required for equipment that is reconditioned by the owner or operator as part of a regular equipment maintenance program.

Informational Note No. 1: Industry ANSI-approved standards are available for application of reconditioned and refurbished equipment.

Informational Note No. 2: The term reconditioned may be interchangeable with the terms rebuilt, refurbished, or remanufactured even though these are sometimes different processes.

Informational Note No. 3: The original listing mark may include the mark of the certifying body and not the entire equipment label.

(B)  Field-Applied Hazard Markings.

Where caution, warning, or danger hazard markings such as labels or signs or labels are required by this Code, the labels markings shall meet the following requirements:

1. The marking shall be of sufficient durability to withstand the environment involved and warn of the hazards using effective words, colors, symbols, or any combination thereof.

Informational Note No. 1: See ANSI Z535.2-2011 (R2017), Environmental and Facility Safety Signs, which describes the design, application, and use of safety signs in facilities and in the environment.

Informational Note No. 2: See ANSI Z535.4-2011 (R2017), Product Safety Signs and Labels, provides guidelines for suitable font sizes, words, colors, symbols, and location requirements for labels which details the design, application, use, and placement of safety signs and labels on a wide variety of products.

(A)  General.

Each disconnecting means shall be legibly marked to indicate its purpose unless located and arranged so the purpose is evident. In other than one- or two-family dwellings, the marking shall include the identification and location of the circuit source that supplies the disconnecting means unless located and arranged so the identification and location of the circuit source is evident. The marking shall be of sufficient durability to withstand the environment involved.

110.26 Spaces About Electrical Equipment.

Access and Working space, and access to and egress from working space, shall be provided, and maintained about all electrical equipment to permit ready and safe operation and maintenance of such equipment. Open equipment doors shall not impede access to and egress from the working space. Access or egress is impeded if one or more simultaneously opened equipment doors restrict working space access to be less than 610 mm (24 in.) wide and 2.0 m (6 1⁄2 ft) high.

110.26(A)(6) Grade, Floor, or Working Platform.

The grade, floor, or platform in the required working shall be kept clear, and the floor, grade, or platform in the working space shall be as level and flat as practical for the entire required depth and width of the working space.

110.29 In Sight From (Within Sight From, Within Sight).

Where this Code specifies that one equipment shall be “in sight from,” “within sight from,” or “within sight of” another equipment, the specified equipment shall be visible and not more than 15 m (50 ft) distant from the other.

(A)  Entrance.

At least one entrance to enclosures for electrical installations as described in 110.31 not less than 610 mm (24 in.) wide and 2.0 m (61⁄2 ft) high shall be provided to give access to the working space about electrical equipment.

Open equipment doors shall not impede access to egress from the working space. Access or egress is impeded if one or more simultaneously opened equipment doors restrict working space access to be less than 610 mm (24 in.) wide and 2.0 m (61⁄2 ft) high.

(A)  Working Space.

Except as elsewhere required or permitted in this Code, equipment likely to require examination, adjustment, servicing, or maintenance while energized shall have clear working space in the direction of access to live parts of the electrical equipment and shall be not less than specified in Table 110.34(A). Distances shall be measured from the live parts, if such are exposed, or from the enclosure front or opening if such are enclosed. The grade, floor, or platform in the required working space shall kept clear, and the floor, grade, or platform in the working space shall be as level and flat as practical for the entire depth and width of the working space.

Exception: Working space shall not be required in back of equipment such as switchgear or control assemblies where there are no renewable or adjustable parts (such as fuses or switches) on the back and where all connections are accessible from locations other than the back. Where rear access is required to work on nonelectrical parts on the back of enclosed equipment, a minimum working space of 762 mm (30 in.) horizontally shall be provided.

Table 110.34(A) Minimum Depth of Clear Working Space at Electrical Equipment

Note: Where the conditions are as follows:

Condition 1 — Exposed live parts on one side of the working space and no live or grounded parts on the other side of the working space, or exposed live parts on both sides of the working space that are effectively guarded by insulating materials.

Condition 2 — Exposed live parts on one side of the working space and grounded parts on the other side of the working space. Concrete, brick, or tile walls shall be considered as grounded.

Condition 3 — Exposed live parts on both sides of the working space.

210.2  Reconditioned Equipment.

Reconditioned equipment shall be listed as “reconditioned” and the original listing mark removed. The following shall not be reconditioned:

1. Equipment that provides ground-fault circuit-interrupter protection for personnel
2. Equipment that provides arc-fault circuit-interrupter protection

(A)  Dwelling Units.

All 125-volt through 250-volt receptacles installed in the following locations specified in 210.8(A)(1) through (A)⁠(11) and supplied by single-phase branch circuits rated 150 volts or less to ground shall have ground-fault circuit-interrupter protection for personnel:

1. Bathrooms
2. Garages and also accessory buildings that have a floor located at or below grade level not intended as habitable rooms and limited to storage areas, work areas, and areas of similar use
3. Outdoors
4. Crawl spaces — at or below grade level
5. Basements

Informational Note: See 760.41(B) and 760.121(B) for power supply requirements for fire alarm systems. Receptacles installed under the exception to 210.8(A)⁠(5) shall not be considered as meeting the requirements of 210.52(G).

6. Kitchens — where the receptacles are installed to serve the countertop surfaces

Exception No. 1: Receptacles that are not readily accessible and are supplied by a branch circuit dedicated to electric snow-melting, deicing, or pipeline and vessel heating equipment shall be permitted to be installed in accordance with 426.28 or 427.22, as applicable.

Exception No. 2: A receptacle supplying only a permanently installed fire alarm or burglar alarm premises security system shall not be required to have be permitted to omit ground-fault circuit-interrupter protection.

Exception No. 3: Listed locking support and mounting weight-supporting ceiling receptacles (WSCR) utilized in combination with compatible weight-supporting attachment fittings (WSAF) installed for the purpose of serving supporting a ceiling luminaire or ceiling-suspended fan shall not be required to bebe permitted to omit ground-fault circuit-interrupter protectedprotection. If a general-purpose convenience receptacle is integral to the ceiling luminaire or ceiling-suspended fan, GFCI protection shall be provided.

Exception No. 4: Factory-installed receptacles that are not readily accessible and are mounted internally to bathroom exhaust fan assemblies shall not require GFCI protection unless required by the installation instructions or listing.

Informational Note: See 760.41(B) and 760.121(B) for power supply requirements for fire alarm systems.

Exception No. 3: Listed locking support and mountingweight-supporting ceiling receptacles (WSCR) utilized in combination with compatible weight-supporting attachment fittings (WSAF) installed for the purpose of servingsupporting a ceiling luminaire or ceiling-suspended fan shall not be required to bebe permitted to omit ground-fault circuit-interrupter protectedprotection. If a general-purpose convenience receptacle is integral to the ceiling luminaire or ceiling-suspended fan, GFCI protection shall be provided.

Exception No. 6: Listed locking support and mountingweight-supporting ceiling receptacles used(WSCR) utilized in combination with compatible weight-supporting attachment fittings (WSAF) installed for the purpose of serving a ceiling luminaire or ceiling-suspended fan shall not be required to be GFCI protectedpermitted to omit GFCI protection. If a general-purpose convenience receptacle is integral to the ceiling luminaire or ceiling-suspended fan, GFCI protection shall be provided.systems.

(B)  Other Than Dwelling Units.

All 125-volt through 250-volt receptacles supplied by single-phase branch circuits rated 150 volts or less to ground, 50 amperes or less, and all receptacles supplied by three-phase branch circuits rated 150 volts or less to ground, 100 amperes or less, installed in the following locations specified in 210.8(B)(1) through (B)(12) shall have ground-fault circuit-interrupter protection for personnel.shall be provided with GFCI protection:

1. Bathrooms
2. Kitchens
3. Kitchens or areasAreas with a sinks and permanent provisions for either food preparation, beverage preparation, or cooking
4. Buffet serving areas with permanent provisions for food serving, beverage serving, or cooking

Sinks — where receptacles or cord-and-plug-connected fixed or stationary appliances are installed within 1.8 m (6 ft) from the top inside edge of the bowl of the sink

Exception No. 1 to (7): In industrial establishments only, where the conditions of maintenance and supervision ensure that only qualified personnel are involved, an assured equipment grounding conductor program in accordance with 590.6(B)(2) shall be permitted for only those receptacle outlets used to supply equipment that would create a greater hazard if power is interrupted or that has a design not compatible with GFCI protection.

Exception  No. 2 to (7): In industrial laboratories, receptacles used to supply equipment where removal of power would introduce a greater hazard shall be permitted to be installed without GFCI protection.

Exception No. 3 to (7): Receptacles located in patient bed locations of Category 2 (general care) or Category 1 (critical care) spaces of health care facilities shall be permitted to comply with 517.21.

(13) Aquariums, bait wells, and similar open aquatic vessels or containers, such as tanks or bowls, where receptacles are installed within 1.8 m (6 ft.) from the top inside edge or rim or from the conductive support framing of the vessel or container

(D)  Specific Appliances.

Unless GFCI protection is provided in accordance with 422.5(B)(3) through (B)(5), the outlets supplying the appliances specified in 422.5(A) shall have GFCI protection in accordance with 422.5(B)(1) or (B)(2).

Where the appliance is a vending machine as specified in 422.5(A)(5) and GFCI protection is not provided in accordance with 422.5(B)(3) or (B)(4), branch circuits supplying vending machines shall have GFCI protection in accordance with 422.5(B)(1) or (B)(2).GFCI protection shall be provided for the branch circuit or outlet supplying the following appliances rated 150 volts or less to ground and 60 amperes or less, single- or 3-phase:

1. Automotive vacuum machines
2. Drinking water coolers and bottle fill stations
3. High-pressure spray washing machines
4. Tire inflation machines
5. Vending machines
6. Sump pumps
7. Dishwashers
8. Electric ranges
9. Wall-mounted ovens
10. Counter-mounted cooking units
11. Clothes dryers
12. Microwave ovens

(F)  Outdoor Outlets.

AllFor dwellings, all outdoor outlets for dwellings, other than those covered in 210.8(A)(3), Exception to (3), that are other than those covered in 210.8(A), Exception No. 1, including outlets installed in the following locations, and supplied by single-phase branch circuits rated 150 volts or less to ground or less, 50 amperes or less, shall have ground-fault circuit-interrupter protection for personnel. be provided with GFCI protection:

1. Garages that have floors located at or below grade level
2. Accessory buildings
3. Boathouses

If equipment supplied by an outlet covered under the requirements of this section is replaced, the outlet shall be supplied with GFCI protection.

Exception: Ground-fault circuit-interrupterGFCI protection shall not be required on lighting outlets other than those covered in 210.8(C).

210.11(C)(4)

 (4)  Garage Branch Circuits.

In addition to the number of branch circuits required by other parts of this section, at least one 120-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 readily accessible 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(A)(1) and (A)(2).

(4)  Garage Branch Circuits.

In addition to the number of branch circuits required by other parts of this section, at least one 120-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 readily accessible 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(A)(1) and (A)(2).

210.12 Arc-Fault Circuit-Interrupter Protection

Arc-fault circuit-interrupter (AFCI) protection shall be providedinstalledas required in 210.12(A), (B), (C), and (D)in accordance with 210.12(B) through (E) by any of the means described in 210.12(A)(1) through (A)(6). The arc-fault circuit interrupterAFCI shall be listed and installed in a readily accessible location.

(1)  General.

(D)  Guest Rooms, Guest Suites, and Patient Sleeping Rooms in Nursing Homes and Limited-Care FacilitiesOther Occupancies.

All 120-volt, single-phase, 15- and 20-ampere branch circuits supplying outlets andor devices installed in guest rooms and guest suites of hotels and motels and, and in areas used exclusively as patient sleeping rooms in nursing homes and limited-care facilities 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.

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 3.3.198.12 and A.3.3.198.12(5) of NFPA 101-2021, Life Safety Code, for the definition of assisted living facilities.

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 Informational Note No. 2 of 215.2(A)(1) for information on  voltage drop on feeder conductors.

(A)  General.

Branch-circuit conductors shall have an ampacity not less than the larger of 210.19(A)(1)(a) or (A)(1)(b) 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 circuit(s)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), it shall be permitted to have 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.

(B)  Branch Circuits Not More Than 600 Volts.

Informational Note No. 1: See 310.14 for ampacity and temperature limitations of conductors.

Informational Note No. 2: See Part II of Article 430 for minimum rating of motor branch-circuit conductors.

(1)  General.

Branch-circuit conductors shall have an ampacity not less than the larger of 210.19(A)(1)(a) or (A)(1)(b) 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.
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 No. 1 to (1)(a): If the assembly, including the overcurrent devices protecting the branch circuit(s), 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).

Exception No. 2 to (1)(a) and (1)(b): 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), it shall be permitted to have an allowable ampacity, in accordance with 310.15, not less than the sum of the continuous load plus the noncontinuous load. 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. 

(E)  Branch Circuits Over 600 Volts.

The ampacity of conductors shall be in accordance with 310.14 and 311.60, as applicable. Branch-circuit conductors over 600 volts shall be sized in accordance with 210.19(B)(1) or (B)(2).

(1)  General.

The ampacity of branch-circuit conductors shall not be less than 125 percent of the designed potential load of utilization equipment that will be operated simultaneously.

(2)  Supervised Installations.

For supervised installations, branch-circuit conductor sizing shall be permitted to be determined by qualified persons under engineering supervision. Supervised installations are defined as those portions of a facility where both of the following conditions are met:

1. Conditions of design and installation are provided under engineering supervision.
2. Qualified persons with documented training and experience in over 600-volt systems provide maintenance, monitoring, and servicing of the system.

210.23 Permissible Loads, Multiple-Outlet Branch Circuits.

In no case shall the load exceed the branch-circuit ampere rating. A branch circuit supplying two or more outlets or receptacles shall supply only the loads specified according to its size as specified inin accordance with 210.23(B)210.23(A) through (DE) and as summarized in 210.24. and Table 210.24.

(A)  10-Ampere Branch Circuits.

A 10-ampere branch circuit shall comply with the requirements of 210.23(A)(1) and (A)(2).

(1)  Loads Permitted for 10-Ampere Branch Circuits.

A 10-ampere branch circuit shall be permitted to supply one or more of the following:

1. Lighting outlets
2. Dwelling unit exhaust fans on bathroom or laundry room lighting circuits
3. A gas fireplace unit supplied by an individual branch circuit

(2)  Loads Not Permitted for 10-Ampere Branch Circuits.

A 10-ampere branch circuit shall not be permitted for any of the following:

1. Supplying receptacle outlets
2. Supplying fixed appliances, except as permitted for individual branch circuits
3. Supplying garage door openers
4. Supplying laundry equipment

(C)  Countertops and Work Surfaces.

In kitchens, pantries, breakfast rooms, dining rooms, and similar areas of dwelling units, receptacle outlets for countertop and work surfaces that are 300 mm (12 in.) or wider shall be installed in accordance with 210.52(C)(2)210.52(C)(1) through (C)(3) and shall not be considered as the receptacle outlets required by 210.52(A).

For the purposes of this section, where using multioutlet assemblies, each 300 mm (12 in.) of multioutlet assembly containing two or more receptacles installed in individual or continuous lengths shall be considered to be one receptacle outlet.

(1)  Wall Spaces.

Receptacle outlets shall be installed so that no point along the wall line is more than 600 mm (24 in.) measured horizontally from a receptacle outlet in that space. The location of the receptacles shall be in accordance with 210.52(C)(3).

Exception No. 1: Receptacle outlets shall not be required directly behind a range, counter-mounted cooking unit, or sink in the installation described in Figure 210.52(C)(1).

Exception No. 2: Where a required receptacle outlet cannot be installed in the wall areas shown in Figure 210.52(C)(1), the receptacle outlet shall be permitted to be installed as close as practicable to the countertop area to be served. The total number of receptacle outlets serving the countertop shall not be less than the number needed to satisfy 210.52(C)(1). These outlets shall be located in accordance with 210.52(C)(3).

(G) Basements, Garages, and Accessory Buildings

For one- and two-family dwellings, and multifamily dwellings, at least one receptacle outlet shall be installed in the areas specified in 210.52(G)(1) through (G)(3). These receptacles shall be in addition to receptacles required for specific equipment. Receptacles supplying only a permanently installed premises security system shall not be considered as meeting these requirements.

210.70 Lighting Outlets Required.

Lighting outlets shall be installed where specified in 210.70(A), (B), and (C).

(A)  Dwelling Units.

In dwelling units, lighting outlets shall be installed in accordance with 210.70(A)(1) and (A)(2).

(1)  Habitable Rooms.

At least one lighting outlet controlled by a listed wall-mounted control device shall be installed in every habitable room, kitchen, laundry area, and bathroom. The wall-mounted control device shall be located near an entrance to the room on a wall.

Exception No. 1: In other than kitchens, laundry areas, and bathrooms, one or more receptacles controlled by a listed wall-mounted control device shall be permitted in lieu of lighting outlets.

Exception No. 2: Lighting outlets shall be permitted to be controlled by occupancy sensors that are (1) in addition to listed wall-mounted control devices or (2) located at a customary wall switch location and equipped with a manual override that will allow the sensor to function as a wall switch.

215.15  Barriers.

Barriers shall be placed such that no uninsulated, ungrounded busbar or terminal is exposed to inadvertent contact by persons or maintenance equipment while servicing load terminations in panelboards, switchboards, switchgear, or motor control centers supplied by feeder taps in 240.21(B) or transformer secondary conductors in 240.21(C) with the disconnecting device, to which the tap conductors are terminated, in the open position.

215.18  Surge Protection.

(A)  Surge-Protective Device.

Where a feeder supplies any of the following, a surge-protective device (SPD) shall be installed:

Dwelling units

Dormitory units

Guest rooms and guest suites of hotels and motels

Areas of nursing homes and limited-care facilities used exclusively as patient sleeping rooms

(B)  Location.

The SPD shall be installed in or adjacent to distribution equipment , connected to the load side of the feeder, that contains branch circuit overcurrent protective device(s) that supply the location specified in 215.18(A).

Informational Note: Surge protection is most effective when closest to the branch circuit. Surges can be generated from multiple sources including, but not limited to, lightning, the electric utility, or utilization equipment.

(C)  Type.

The SPD shall be a Type 1 or Type 2 SPD.

(D)  Replacement.

Where the distribution equipment supplied by the feeder is replaced, all of the requirements of this section shall apply.
(E)  Ratings.

SPDs shall have a nominal discharge current rating (In) of not less than 10kA.

Informational Note: Lead lengths of conductors to the SPD should be kept as short as possible to reduce let-through voltages.

220.1  Scope.

This article provides requirements for calculating branch-circuit, feeder, and service loads. Part I provides general requirements for calculation methods. Part II provides calculation methods for branch-circuit loads. Parts III and Part IV provide calculation methods for feeder and service loads. Part V provides calculation methods for farm loads. Part VI provides calculation methods for health care facilities. Part VII provides calculation methods for marinas, boatyards, floating buildings, and commercial and noncommercial docking facilities.

Informational Note No. 1: See examples in Informative Annex D for examples.

Informational Note No. 2: See Figure Informational Note 220.1 for information on the organization of Article 220this article.

(C)  Floor Area.

The floor area for each floor shall be calculated from the outside dimensions of the building, dwelling unit, or other area involved. For dwelling units, the calculated floor area shall not include open porches , garages, or unused or unfinished spaces not adaptable for future use. or unfinished areas not adaptable for future use as a habitable room or occupiable space.

220.57 Electric Vehicle Supply Equipment (EVSE) Load.

The EVSE load shall be calculated at either 7200 watts (volt-amperes) or the nameplate rating of the equipment, whichever is larger.

220.70  Energy Management Systems (EMSs).

If an energy management system (EMS) is used to limit the current to a feeder or service in accordance with 750.30, , a single value equal to the maximum ampere setpoint of the EMS shall be permitted to be used in load calculations for the feeder or service.

The set point value of the EMS shall be considered a continuous load for the purposes of load calculations

Part VI.  Health Care Facilities

220.110  Receptacle Loads — Health Care Facilities.

Receptacle loads calculated in accordance with 220.14(H) and (I) and supplied by branch circuits not exceeding 150 volts to ground shall be permitted to be subjected to the demand factors provided in Table 220.110(1) and Table 220.110(2) for health care facilities.

Informational Note No. 1: See Article 100 for the definitions of patient care space categories.

Informational Note No. 2: See 220.14(I) for the calculation of receptacle outlet loads.

Table 220.110(1) Demand Factors for Health Care Receptacle Loads Receptacles Supplied by General-Purpose Branch Circuits in Category 1 and Category 2 Patient Care Spaces

Table 220.110(2) Demand Factors for Receptacles Supplied by General-Purpose Branch Circuits in Category 3 and Category 4 Patient Care Spaces

Part VII.  Marinas, Boatyards, Floating Buildings, and Commercial and Noncommercial Docking Facilities

220.120  Receptacle Loads.

General lighting and other loads in marinas, boatyards, floating buildings, and commercial and noncommercial docking facilities shall be calculated in accordance with Part III of this article and, in addition, the demand factors set forth in Table 220.120 shall be permitted for each service 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) of Table 220.120. Where demand factors of Table 220.120 are applied, the demand factor specified in 220.61(B) shall not be permitted.

Informational Note: These demand factors could be inadequate in areas of extreme hot or cold temperatures with loaded circuits for heating, air-conditioning, or refrigerating equipment.

Table 220.120 Demand Factors for Shore Power Receptacle Loads

Notes:

1. Where shore power accommodations provide two receptacles specifically for an individual boat slip and these receptacles have different voltages (e.g., one 30-ampere, 125-volt and one 50-ampere, 125/250-volt), only the receptacle with the larger kilowatt demand shall be required to be calculated.
2. For each shore powered pedestal being installed that includes an individual kilowatt-hour submeters for each slip and is being calculated using the criteria listed in Table 220.120, the total demand amperes shall be permitted to be multiplied by 0.9 to achieve the final demand amperes of the facility.
3. If a circuit feeding a boat hoist and shore power for the same boat slip is shared, only the load with the larger kilowatt demand shall be required to be counted in the load calculation.

225.5  Size of Conductors 1000 Volts, Nominal, or Less.

The ampacity of outdoor branch-circuit and feeder conductors shall be in accordance with 310.14 based on loads as determined under 220.10 and Part III of Article 220.

225.7  Lighting Equipment Installed Outdoors.

(A)  General.

For the supply of lighting equipment installed outdoors, the branch circuits shall comply with Article 210 and 225.7(B) through (D).

(B)  Common Neutral.

The ampacity of the neutral conductor shall not be less than the maximum net calculated load current between the neutral conductor and all ungrounded conductors connected to any one phase of the circuit.

(C)  277 Volts to Ground.

Circuits exceeding 120 volts, nominal, between conductors and not exceeding 277 volts, nominal, to ground shall be permitted to supply luminaires for illumination of outdoor areas of industrial establishments, office buildings, schools, stores, and other commercial or public buildings.

(D)  1000 Volts Between Conductors.

Circuits exceeding 277 volts, nominal, to ground and not exceeding 1000 volts, nominal, between conductors shall be permitted to supply the auxiliary equipment of electric-discharge lamps in accordance with 210.6(D)(1).

225.41  Emergency Disconnects.

For one-and two-family dwelling units, an emergency disconnecting means shall be installed.

(A)  General.

(1)  Location.

The disconnecting means shall be installed in a readily accessible outdoor location on or within sight of the dwelling unit.

(2)  Rating.

The disconnecting means shall have a short-circuit current rating equal to or greater than the available fault current.

(3)  Grouping.

If more than one disconnecting means is provided, they shall be grouped.

(B)  Identification of Other Emergency Disconnects.

Where emergency disconnects are installed for other systems that are not located adjacent to the emergency disconnect required by this section, a plaque or directory identifying the location of all emergency disconnects shall be located adjacent to the disconnecting means required by this section.

(C)  Marking.

The disconnecting means shall be marked as EMERGENCY DISCONNECT.

Markings shall comply with 110.21(B) and all of the following:

1. The marking or labels shall be located on the outside front of the disconnect enclosure with red background and white text.

The letters shall be least 13 mm (1⁄2 in.) high.

(C)  Barriers.

Barriers shall be placed in service equipment such that no uninsulated, ungrounded service busbar or service terminal is exposed to inadvertent contact by persons or maintenance equipment while servicing load terminations with the service disconnect in the open position.

230.67  Surge Protection.

(A)  Surge-Protective Device.

All services supplying dwelling unitsthe following occupancies shall be provided with a surge-protective device (SPD).:

1. Dwelling units
2. Dormitory units
3. Guest rooms and guest suites of hotels and motels
4. Areas of nursing homes and limited-care facilities used exclusively as patient sleeping rooms

Informational Note: See 517.10(B)(2).

(B)  Location.

The SPD shall be an integral part of the service equipment or shall be located immediately adjacent there to.

Exception: The SPD shall not be required to be located in the service equipment as required in 230.67(B)(B) if located at each next level distribution equipment downstream toward the load.

(C)  Type.

The SPD shall be a Type 1 or Type 2 SPD.

(D)  Replacement.

Where service equipment is replaced, all of the requirements of this section shall apply.

(B)  Two to Six Service Disconnecting Means.

Two to six service disconnects shall be permitted for each service permitted by 230.2 or for each set of service-entrance conductors permitted by 230.40, Exception No. 1, 3, 4, or 5. The two to six service disconnecting means shall be permitted to consist of a combination of any of the following:

1. Separate enclosures with a main service disconnecting means in each enclosure.
2. Panelboards with a main service disconnecting means in each panelboard enclosure.
3. Switchboard(s) where there is only one service disconnect in each separate vertical section where there are barriers separating each vertical section with barriers provided between each vertical section to maintain the inadvertent contact protection required in 230.62 based on access from the adjacent section(s).
4. Service disconnects in switchgear, transfer switches, or metering centers where each disconnect is located in a separate compartment.
5. Metering centers with a main service disconnecting means in each metering center.
6. Motor control center(s) where there is only one service disconnect in a motor control center unit and a maximum of two service disconnects provided in a single motor control center with barriers provided between each motor control center unit or compartment containing a service disconnect to maintain the inadvertent contact protection required in 230.62 based on access from adjacent motor control center unit(s) or compartment(s).

Exception to (2), (3), (4), (5), and (6): Existing service equipment, installed in compliance with previous editions of this Code that permitted multiple service disconnecting means in a single enclosure, section, or compartment, shall be permitted to contain a maximum of six service disconnecting means.

Informational Note No. 1: Metering centers are addressed in See UL 67, Standard for Panelboards, for information on metering centers.

Informational Note No. 2: Examples of separate enclosures with a main service disconnecting means in each enclosure include but are not limited to motor control centers, fused disconnects, and circuit breaker enclosures., and transfer switches that are suitable for use as service equipment.

Informational Note No. 3: Transfer switches are provided with one service disconnect or multiple service disconnects for multiple services in separate compartments

230.85  Emergency Disconnects.

For one- and two-family dwelling units, all service conductors shall terminate in disconnecting means having a short-circuit current rating equal to or greater than the available fault current, installed in a readily accessible outdoor location. If more than one disconnect is provided, they shall be grouped. Each disconnect shall be one of the following: an emergency disconnecting means shall be installed.

1. Service disconnects marked as follows:

EMERGENCY DISCONNECT,

SERVICE DISCONNECT

2. Meter disconnects installed per 230.82(3) and marked as follows:

EMERGENCY DISCONNECT,

METER DISCONNECT,

NOT SERVICE EQUIPMENT

3. Other listed disconnect switches or circuit breakers on the supply side of each service disconnect that are suitable for use as service equipment and marked as follows:

EMERGENCY DISCONNECT,

NOT SERVICE EQUIPMENT

Reference NEC for complete Text

Article  235  Branch Circuits Over 1000 Volts ac, 1500 Volts dc, Nominal

235.1  Scope.

This article includes general requirements for installations for branch circuits over 1000 volts ac or 1500 volts dc, nominal.

Reference NEC for complete Text

240.2  Reconditioned Equipment.

(A)  Reconditioning Not Permitted.

The following equipment shall not be reconditioned:

(1)   Equipment providing ground-fault protection of equipment

(2)   Ground-fault circuit interrupters

(3)   Low-voltage fuse holders and low-voltage nonrenewable fuses

(4)   Molded-case circuit breakers

(5)   Low-voltage power circuit breaker electronic trip units.

(B)  Reconditioning Permitted.

The following equipment shall be permitted to be reconditioned:

(1)   Low-voltage power circuit breakers

(2)   Electromechanical protective relays and current transformers

Reconditioned equipment shall be listed as reconditioned and comply with 110.21(A)(2).

(B)  Overcurrent Devices Rated 800 Amperes or Less.

The next higher standard overcurrent device rating (above the ampacity of the conductors being protected) shall be permitted to be used, provided all of the following conditions are met:

1. The conductors being protected are not part of a branch circuit supplying more than one receptacle for cord-and-plug-connected portable loads.
2. The ampacity of the conductors does not correspond with the standard ampere rating of a fuse or a circuit breaker without overload trip adjustments above its rating (but that shall be permitted to have other trip or rating adjustments).
3. The next higher standard rating selected does not exceed 800 amperes.

If the overcurrent protective device is an adjustable trip device, installed in accordance with 240.4(B)(1), (B)(2), and (B)(3), it shall be permitted to be set to a value that does not exceed the next higher standard value above the ampacity of the conductors being protected as shown in Table 240.6(A) where restricted access in accordance with 240.6(C) is provided.

(D)  Small Conductors.

(3)  14 AWG Copper-Clad Aluminum.

10 amperes, provided all the following conditions are met:

1. Continuous loads do not exceed 8 amperes
2. Overcurrent protection is provided by one of the following:
3. Branch-circuit-rated circuit breakers are listed and marked for use with 14 AWG copper-clad aluminum conductor.
4. Branch-circuit-rated fuses are listed and marked for use with 14 AWG copper-clad aluminum conductor.

(A)  Fuses and Fixed-Trip Circuit Breakers.

The standard ampere ratings for fuses and inverse time circuit breakers shall be considered as shown in Table 240.6(A). Additional standard ampere ratings for fuses shall be 1, 3, 6, 10, and 601. The use of fuses and inverse time circuit breakers with nonstandard ampere ratings shall be permitted.

Table 240.6(A)(a) Standard Ampere Ratings for Fuses and Inverse Time Circuit Breakers

Table 240.6(A) Standard Ampere Ratings for Fuses and Inverse Time Circuit Breakers

(D)  Remotely Accessible Adjustable-Trip Circuit Breakers.

A circuit breaker(s) that is can be adjusted remotely to modify the adjusting means shall be permitted to have an ampere rating(s) that is equal to the adjusted current setting (long-time pickup setting). Remote access shall be achieved by one of the following methods:

1. Connected directly through a local nonnetworked interface.
2. Connected through a networked interface complying with one of the following methods:
3. The circuit breaker and associated software for adjusting the settings are identified as being evaluated for cybersecurity.
4. A cybersecurity assessment of the network is completed. Documentation of the assessment and certification shall be made available to those authorized to inspect, operate, and maintain the system.

Informational Note No. 1: See ANSI/ISA 62443, Cybersecurity Standards series, UL 2900 Cybersecurity Standard series, or the NIST Framework for Improving Critical Infrastructure Cybersecurity, Version 1.1 for assessment requirements.

Informational Note No. 2: Examples of the commissioning certification used to demonstrate the system has been investigated for cybersecurity vulnerabilities could be one of the following:

1. The ISA Security Compliance Institute (ISCI) conformity assessment program
2. Certification of compliance by a nationally recognized test laboratory
3. Manufacturer certification for the specific type and brand of system provided

Informational Note No. 3: Cybersecurity is a specialized field requiring constant, vigilant attention to security vulnerabilities that could arise due to software defects, system configuration changes, or user interactions. Installation of devices that can be secured is an important first step but not sufficient to guarantee a secure system.

240.7  Listing Requirements.

The following shall be listed:

1. Branch-circuit overcurrent protective devices
2. Relays and circuit breakers providing ground-fault protection of equipment
3. Ground-fault circuit interrupter devices

240.11  Selective Coordination.

If one or more feeder overcurrent protective devices are required to be selectively coordinated with a service overcurrent protective device by other requirements in this Code, all feeder overcurrent protective devices supplied directly by the service overcurrent protective device shall be selectively coordinated with the service overcurrent protective device.

240.16  Interrupting Ratings.

Branch-circuit overcurrent protective devices shall have an interrupting rating no less than 5000 amperes.

(A)  Accessibility.

Circuit breakers and switches containing fuses shall be readily accessible and installed so that the center of the grip of the operating handle of the switch or circuit breaker, when in its highest position, is not more than 2.0 m (6 ft 7 in.) above the floor or working platform, unless one of the following applies:

1. For busways, as provided in 368.17(C).
2. For supplementary overcurrent protection, as described in 240.10.
3. For overcurrent protective devices, as described in 225.40 and 230.92.
4. For overcurrent protective devices adjacent to utilization equipment that they supply, access shall be permitted to be by portable means.

Exception: The use of a tool shall be permitted to access overcurrent protective devices located within listed industrial control panels, or similar enclosureswithin enclosures designed for hazardous (classified) locations or enclosures to protect against environmental conditions. An enclosure within the scope of this exception, and all overcurrent protective device(s) within such enclosures as judged with the enclosure open, shall comply with the accessibility provisions of 240.24(A).

(E)  Not Located in Bathrooms.

In dwelling units, dormitory units, and guest rooms or guest suites, overcurrentOvercurrent protective  devices, other than supplementary overcurrent protection, shall not be located in bathrooms, showering facilities, or locker rooms with showering facilities.

242.2 Reconditioned Equipment.

SPDs and surge arresters shall not be reconditioned.

242.9  Indicating.

An SPD shall provide indication that it is functioning properly.

Article 245 Overcurrent  Protection for Systems Rated Over 1000 Volts ac, 1500 Volts dc

This article covers overcurrent protection requirements for systems over 1000 volts ac, 1500 volts dc, nominal.

245.1  Scope.

245.2 Reconditioned Equipment.

245.21 Circuit-Interrupting Devices.

245.26 Feeders and Branch Circuits.

245.27 Additional Requirements for Feeders.

Reference NEC for complete Text

250.24  Grounding of Service-Supplied Alternating-Current Systems.

 Reference NEC for complete Text

(2)   Conductors Connected in Parallel in Two or More Raceways or Cables Connected in Parallel.

If the ungrounded service-entrance conductors are connected in parallel in two or more raceways or cables, the grounded conductors shall also be installed in each raceway or cable and shall be connected in parallel. The size of theeach grounded conductor(s) in each raceway or cable shall not be smaller than 1/0 AWG and shall be sized in accordance with 250.24(D)(2)(a) or (D)(2)(b) in accordance with 250.24(D)(1). be based on the largest ungrounded conductor in each raceway or cable, or the sum of the circular mil areas of the largest ungrounded conductors from each set connected in parallel in each raceway or cable in accordance with in 250.24(D)(1) , but not smaller than 1/0 AWG

(C)  Outdoor Source.

If the source of the separately derived system is located outside the building or structure supplied, a grounding electrode connection shall be made at the source location to one or more grounding electrodes in complianceaccordance with 250.50. In addition, the installation shall complybe in accordance with 250.30(A) for grounded systems or with 250.30(B) for ungrounded systems.

250.36  High-Impedance Grounded Neutral Systems — 480 Volts to 1000 Volts.

High-impedanceImpedance grounded neutral systems in which a grounding impedance, usually device, typically a resistor, limits the ground-fault current to a low value shall be permitted for 3-phase ac systems of 480 volts to 1000 volts if all the following conditions are met:

Reference NEC for complete Text

250.50  Grounding Electrode System.

All grounding electrodes as described in 250.52(A)(1) through (A)(7) that are present at each building or structure served shall be bonded together to form the grounding electrode system. WhereIf none of these grounding electrodes exist, one or more of the grounding electrodes specified in 250.52(A)(4) through (A)⁠(8) shall be instal⁠led and used.

Exception: Concrete-encased electrodes of existing buildings or structures shall not be required to be part of the grounding electrode system whereif the steel reinforcing bars or rods are not accessible for use without disturbing the concrete.

(3)  Concrete-Encased Electrode.

A concrete-encased electrode shall consist of at least 6.0 m (20 ft) of either (1) or (2)of the following:

1. One or more bare or zinc galvanized or other electrically conductive coated steel reinforcing bars or rods of not less than 13 mm (1⁄2) in diameter, installed in one continuous 6.0 m (20 ft) length, or if in multiple pieces connected together by the usual steel tie wires, exothermic welding, welding, or other effective means to create a 6.0 m (20 ft) or greater length; or

(B)  Not Permitted for Use as Grounding Electrodes.

The following systems and materials shall not be used as grounding electrodes:

1. Metal underground gas piping systems
2. Aluminum
3. The structures and structural reinforcing steelrebardescribed in 680.26(B)(1) and (B)(2)

(G)  Enclosures with Ventilation Openings.

Grounding electrode conductors shall not be installed through a ventilation opening of an enclosure.

250.70  Methods of Grounding and Bonding Conductor Connection to Electrodes.

(A)  General.

The grounding or bonding conductor shall be connected to the grounding electrode by exothermic welding, listed lugs, listed pressure connectors, listed clamps, or other listed means. Connections depending on solder shall not be used. Ground clamps shall be listed for the materials of the grounding electrode and the grounding electrode conductor and, whereif used on pipe, rod, or other buried electrodes, shall also be listed for direct soil burial or concrete encasement. Not more than one conductor shall be connected to the grounding electrode by a single clamp or fitting unless the clamp or fitting is listed for multiple conductors. One of the following methods shall be used:

1. A pipe fitting, pipe plug, or other approved device screwed into a pipe or pipe fitting
2. A listed bolted clamp of cast bronze or brass, or plain or malleable iron
3. For indoor communications purposes only, a listed sheet metal strap-type ground clamp having a rigid metal base that seats on the electrode and having a strap of such material and dimensions that it is not likely to stretch during or after installation
4. An equally substantial approved means

(B)  Indoor Communications Systems.

For indoor communications purposes only, a listed sheet metal strap-type ground clamp having a rigid metal base that seats on the electrode and having a strap of such material and dimensions that it is not likely to stretch during or after installation shall be permitted.

Informational Note: Listed ground clamps that are identified for direct burial are also suitable for concrete encasement.

(A)  The Intersystem Bonding Termination Device.

An intersystem bonding termination (IBT) for connecting intersystem bonding conductors shall be provided external to enclosures at the service equipment or metering equipment enclosure and at the disconnecting means for any additional buildings or structures that are supplied by a feeder or branch circuit. If an IBT is used, it shall comply with the following:

1. Be accessible for connection and inspection.
2. Consist of a set of terminals with the capacity for connection of not less than three intersystem bonding conductors.
3. Not interfere with opening the enclosure for a service, building or structure disconnecting means, or metering equipment.
4. Be securely mounted as follows:
   1. At the service equipment, betosecurely mounted and electrically connected to ana metal enclosure for the service equipment, to thea metal meter enclosure, for an exposed nonflexible metallicmetal service raceway, or be mounted at one of these enclosures and be connected to the metal enclosure or to the grounding electrode conductor with a minimum 6 AWG copper conductor.
   2. At the disconnecting means for a building or structure that is supplied by a feeder or branch circuit, be securely mounted and electrically connected to the metallicmetal enclosure for the building or structure disconnecting means, or be mounted at the disconnecting means and be connected to the metallicmetal enclosure for the grounding electrode conductor with a minimum 6 AWG copper conductor.
5. The terminals shall beBelisted as grounding and bonding equipment.

Exception: In existing buildings or structures where, if any of the intersystem bonding and grounding electrode conductors required by 770.100(B)(2), 800.100(B)(2), 810.21(F)(2), and 820.100, and 830.100 exist, installation of the intersystem bonding termination isan IBT shall not be required. An accessible means external to enclosures for connecting intersystem bonding and grounding electrode conductors shall be permitted at the service equipment and at the disconnecting means for any additional buildings or structures that are supplied by a feeder or branch circuit by at least one of the following means:

1. Exposed nonflexible metallic metal raceways
2. An exposed grounding electrode conductor
3. Approved means for the external connection of a copper or other corrosion-resistant bonding or grounding electrode conductor to the grounded raceway or equipment

250.106  Lightning Protection Systems.

The lightning protection system ground terminals shall be bonded to the building or structure grounding electrode system.

Informational Note No. 1: See 250.60 for use of strike termination devices. For further information, see NFPA 780-2020, Standard for the Installation of Lightning Protection Systems, which contains detailed information on grounding, bonding, and sideflash distance from lightning protection systems.

Informational Note No. 2: For further information, seeSeeNFPA 780-2020, Standard for the Installation of Lightning Protection Systems, which contains detailed information on grounding, bonding, and sideflash distance from lightning protection systems.

Informational Note No. 2: Metal raceways, enclosures, frames, and other non-current-carrying metal parts of electrical equipment installed on a building equipped with a lightning protection system may require bonding or spacing from the lightning protection conductors in accordance with NFPA 780-2020, Standard for the Installation of Lightning Protection Systems.

(f) If liquid tight flexible metal conduit contains a stainless steel core, a wire-type equipment grounding conductor or a bonding jumper in accordance with 250.102(E)(2) shall be installed.

(C)  Replacement of Nongrounding Receptacle Replacement or Snap Switch and Branch Circuit Extensions.

The equipment grounding conductor ofthat is connected to a grounding-type receptacle, a snap switch with an equipment grounding terminal, or a branch-circuit extension shall be permitted to be connected to any of the following:

1. Any accessible point on the grounding electrode system as described in 250.50
2. Any accessible point on the grounding electrode conductor
3. The equipment grounding terminal bar within the enclosure where the branch circuit for the receptacle or branch circuit originates
4. An equipment grounding conductor that is part of another branch circuit that originates from the enclosure where the branch circuit for the receptacle or branch circuit originates
5. For grounded systems, the grounded service conductor within the service equipment enclosure
6. For ungrounded systems, the grounding terminal bar within the service equipment enclosure

Informational Note No. 1: See 406.4(D) for the use of a ground-fault circuit-interrupting type of receptacle.

Informational Note No. 2: See 404.9(B) for requirements regarding grounding of snap switches.

250.140  Frames of Ranges and Clothes Dryers.

Frames of electric ranges, wall-mounted ovens, counter-mounted cooking units, clothes dryers, and outlet or junction boxes that are part of the circuit for these appliances shall be connected to the equipment grounding conductor in the manner specified by 250.134 or 250.138accordance with 250.140(A) or the grounded conductor in accordance with 250.140(B).

Exception: For existing branch-circuit installations only if an equipment grounding conductor is not present in the outlet or junction box, the frames of electric ranges, wall-mounted ovens, counter-mounted cooking units, clothes dryers, and outlet or junction boxes that are part of the circuit for these appliances shall be permitted to be connected to the grounded circuit conductor if all the following conditions are met.

(A)  Equipment Grounding Conductor Connections.

The circuit supplying the appliance shall include an equipment grounding conductor. The frame of the appliance shall be connected to the equipment grounding conductor in the manner specified by 250.134 or 250.138.

(B)  Grounded Conductor Connections.

For existing branch-circuit installations only, if an equipment grounding conductor is not present in the outlet or junction box the frame of the appliance shall be permitted to be connected to the grounded conductor if all the conditions in the following list items (1), (2), and (3) are met and the grounded conductor complies with either list item (4) or (5):

1. The supply circuit is 120/240-volt, single-phase, 3-wire; or 208Y/120-volt derived from a 3-phase, 4-wire, wye-connected system.
2. The grounded conductor is not smaller than 10 AWG copper or 8 AWG aluminum or copper-clad aluminum.
3. Grounding contacts of receptacles furnished as part of the equipment are bonded to the equipment.
4. The grounded conductor is insulated, or the grounded conductor is uninsulated and part of a Type SE service-entrance cable and the branch circuit originates at the service equipment.
5. The grounded conductor is part of a Type SE service-entrance cable that originates in equipment other than a service. The grounded conductor shall be insulated or field covered within the supply enclosure with listed insulating material, such as tape or sleeving to prevent contact of the uninsulated conductor with any normally non-current-carrying metal parts.

250.148  Continuity of Equipment Grounding Conductors and Attachment in Boxes.

If circuit conductors are spliced within a box or terminated on equipment within or supported by a box, all wire-type equipment grounding conductor(s) associated with any of those circuit conductors shall be connected within the box or to the box in accordancethe installation shall comply with 250.8 and 250.148(A) through (D).

Exception: The equipment grounding conductor permitted in 250.146(D) shall not be required to be connected to the other equipment grounding conductors or to the box.

(A)  Connections and Splices.

All equipment grounding conductors that are spliced or terminated within the box shall be connected together. Connections and splices shall be made in accordance with 110.14(B)and 250.8 except that insulation shall not be required.

(B)  Equipment Grounding Conductor Continuity.

The arrangement of grounding connections shall be such that the disconnection or the removal of a luminaire, receptacle, or other device fed from the box does not interrupt the electrical continuity of the equipment grounding conductor(s) providing an effective ground-fault current path.

(C)  Metal Boxes.

A connection used for no other purpose shall be made between the metal box and the equipment grounding conductor(s). in accordance with 250.8 The equipment bonding jumper or equipment grounding conductor shall be sized from Table 250.122 based on the largest overcurrent device protecting circuit conductors in the box.

(D)  Nonmetallic Boxes.

One or more equipment grounding conductors brought into a nonmetallic outlet box shall be arranged such thatto provide a connection can be made to any fitting or device in that box requiring connection to an equipment grounding conductor.