zmVault/nfpa-70_230_services.md

id, aliases, tags, title

id	aliases	tags	title
	nec-230	authorship/other destiny/uncertain exclude-from-word-count status/draft topic/construction/electrical type/media/reference	Article 230 Services

Article 230 Services

230.1 Scope.

This article covers nfpa-70_100_definitions#Service Conductors. and equipment for control and protection of nfpa-70_100_definitions#Service. and their installation requirements.

[!info] Informational Note: See Figure 230.1.

Figure 230.1 Services.

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Part I. General

230.2 Number of Services.

A building or other structure served shall be supplied by only one service unless permitted in 230.2(A) through (D). For the purpose of #^40e2 only, underground sets of conductors, 1/0 AWG and larger, running to the same location and connected together at their supply end but not connected together at their load end shall be considered to be supplying one service.

230.2(A) Special Conditions.

Additional services shall be permitted to supply the following:

• (1) Fire pumps

• (2) Emergency systems

• (3) Legally required standby systems

• (4) Optional standby systems

• (5) Parallel power production systems

• (6) Systems designed for connection to multiple sources of supply for the purpose of enhanced reliability

230.2(B) Special Occupancies.

By special permission, additional services shall be permitted for either of the following:

• (1) Multiple-occupancy buildings where there is no available space for service equipment accessible to all occupants

• (2) A single building or other structure sufficiently large to make two or more services necessary

230.2(C) Capacity Requirements.

Additional services shall be permitted under any of the following:

• (1) Where the capacity requirements are in excess of 2000 amperes at a supply voltage of 1000 volts or less

• (2) Where the load requirements of a single-phase installation are greater than the serving agency normally supplies through one service

• (3) By special permission

230.2(D) Different Characteristics.

Additional services shall be permitted for different voltages, frequencies, or phases, or for different uses, such as for different rate schedules.

230.2(E) Identification.

Where a building or structure is supplied by more than one service, or any combination of branch circuits, feeders, and services, a permanent plaque or directory shall be installed at each service disconnect location denoting all other services, feeders, and branch circuits supplying that building or structure and the area served by each. See 225.37.

230.3 One Building or Other Structure Not to Be Supplied Through Another.

Service conductors supplying a building or other structure shall not pass through the interior of another building or other structure.

230.6 Conductors Considered Outside the Building.

Conductors shall be considered outside of a building or other structure under any of the following conditions:

• (1) Where installed under not less than 50 mm (2 in.) of concrete beneath a building or other structure

• (2) Where installed within a building or other structure in a raceway that is encased in concrete or brick not less than 50 mm (2 in.) thick

• (3) Where installed in any vault that meets the construction requirements of Article 450, Part III

• (4) Where installed in conduit and under not less than 450 mm (18 in.) of earth beneath a building or other structure

• (5) Where installed within rigid metal conduit (Type RMC) or intermediate metal conduit (Type IMC) used to accommodate the clearance requirements in 230.24 and routed directly through an eave but not a wall of a building

230.7 Other Conductors in Raceway or Cable.

Conductors other than service conductors shall not be installed in the same service raceway or service cable in which the service conductors are installed.

[!important] Exception No. 1: Grounding electrode conductors or supply side bonding jumpers or conductors shall be permitted within service raceways.

[!important] Exception No. 2: Load management control conductors having overcurrent protection shall be permitted within service raceways.

230.8 Raceway Seal.

Where a service raceway enters a building or structure from an underground distribution system, it shall be sealed in accordance with 300.5(G). Spare or unused raceways shall also be sealed. Sealants shall be identified for use with the cable insulation, shield, or other components.

230.9 Clearances on Buildings.

Service conductors and final spans shall comply with 230.9(A), (B), and (C).

230.9(A) Clearances.

Service conductors installed as open conductors or multiconductor cable without an overall outer jacket shall have a clearance of not less than 900 mm (3 ft) from windows that are designed to be opened, doors, porches, balconies, ladders, stairs, fire escapes, or similar locations.

[!important] Exception: Conductors run above the top level of a window shall be permitted to be less than the 900 mm (3 ft) requirement.

230.9(B) Vertical Clearance.

The vertical clearance of final spans above, or within 900 mm (3 ft) measured horizontally of platforms, projections, or surfaces that will permit personal contact shall be maintained in accordance with 230.24(B).

230.9(C) Building Openings.

Overhead service conductors shall not be installed beneath openings through which materials may be moved, such as openings in farm and commercial buildings, and shall not be installed where they obstruct entrance to these building openings.

230.10 Vegetation as Support.

Vegetation such as trees shall not be used for support of overhead service conductors or service equipment.

Part II. Overhead Service Conductors

230.22 Insulation or Covering.

Individual conductors shall be insulated or covered.

[!important] Exception: The grounded conductor of a multiconductor cable shall be permitted to be bare.

230.23 Size and Ampacity.

230.23(A) General.

Conductors shall have sufficient ampacity to carry the current for the load as calculated in accordance with Article 220 and shall have adequate mechanical strength.

230.23(B) Minimum Size.

The conductors shall not be smaller than 8 AWG copper or 6 AWG aluminum or copper-clad aluminum.

[!important] Exception: Conductors supplying only limited loads of a single branch circuit --- such as small polyphase power, controlled water heaters, and similar loads --- shall not be smaller than 12 AWG hard-drawn copper or equivalent.

230.23(C) Grounded Conductors.

The grounded conductor shall not be less than the minimum size as required by 250.24(C).

230.24 Clearances.

Overhead service conductors shall not be readily accessible and shall comply with 230.24(A) through (E) for services not over 1000 volts, nominal.

230.24(A) Above Roofs.

Conductors shall have a vertical clearance of not less than 2.5 m (8 ft) above the roof surface. The vertical clearance above the roof level shall be maintained for a distance of not less than 900 mm (3 ft) in all directions from the edge of the roof.

[!important] Exception No. 1: The area above a roof surface subject to pedestrian or vehicular traffic shall have a vertical clearance from the roof surface in accordance with the clearance requirements of 230.24(B).

[!important] Exception No. 2: Where the voltage between conductors does not exceed 300 and the roof has a slope of 100 mm in 300 mm (4 in. in 12 in.) or greater, a reduction in clearance to 900 mm (3 ft) shall be permitted.

[!important] Exception No. 3: Where the voltage between conductors does not exceed 300, a reduction in clearance above only the overhanging portion of the roof to not less than 450 mm (18 in.) shall be permitted if (1) not more than 1.8 m (6 ft) of overhead service conductors, 1.2 m (4 ft) horizontally, pass above the roof overhang, and (2) they are terminated at a through-the-roof raceway or approved support.

[!info] Informational Note: See 230.28 for mast supports.

[!important] Exception No. 4: The requirement for maintaining the vertical clearance 900 mm (3 ft) from the edge of the roof shall not apply to the final conductor span where the service drop or overhead service conductors are attached to the side of a building.

[!important] Exception No. 5: Where the voltage between conductors does not exceed 300 and the roof area is guarded or isolated, a reduction in clearance to 900 mm (3 ft) shall be permitted.

230.24(B) Vertical Clearance for Overhead Service Conductors.

Overhead service conductors, where not in excess of 1000 volts, nominal, shall have the following minimum clearance from final grade:

• (1) 3.0 m (10 ft) --- at the electrical service entrance to buildings, also at the lowest point of the drip loop of the building electrical entrance, and above areas or sidewalks accessible only to pedestrians, measured from final grade or other accessible surface only for overhead service conductors supported on and cabled together with a grounded bare messenger where the voltage does not exceed 150 volts to ground

• (2) 3.7 m (12 ft) --- over residential property and driveways, and those commercial areas not subject to truck traffic where the voltage does not exceed 300 volts to ground

• (3) 4.5 m (15 ft) --- for those areas listed in the 3.7 m (12 ft) classification where the voltage exceeds 300 volts to ground

• (4) 5.5 m (18 ft) --- over public streets, alleys, roads, parking areas subject to truck traffic, driveways on other than residential property, and other land such as cultivated, grazing, forest, and orchard

• (5) 7.5 m (241/2 ft) over tracks of railroads

230.24(C) Clearance from Building Openings.

See 230.9.

230.24(D) Clearance from Swimming Pools.

See 680.9.

230.24(E) Clearance from Communication Wires and Cables.

Clearance from communication wires and cables shall be in accordance with 800.44(A)(4).

230.26 Point of Attachment.

The point of attachment of the overhead service conductors to a building or other structure shall provide the minimum clearances as specified in 230.9 and 230.24. In no case shall this point of attachment be less than 3.0 m (10 ft) above finished grade.

230.27 Means of Attachment.

Multiconductor cables used for overhead service conductors shall be attached to buildings or other structures by fittings identified for use with service conductors. Open conductors shall be attached to fittings identified for use with service conductors or to noncombustible, nonabsorbent insulators securely attached to the building or other structure.

230.28 Service Masts as Supports.

Only power service-drop or overhead service conductors shall be permitted to be attached to a service mast. Service masts used for the support of service-drop or overhead service conductors shall be installed in accordance with 230.28(A) and (B).

230.28(A) Strength.

The service mast shall be of adequate strength or be supported by braces or guy wires to withstand safely the strain imposed by the service-drop or overhead service conductors. Hubs intended for use with a conduit that serves as a service mast shall be identified for use with service-entrance equipment.

230.28(B) Attachment.

Service-drop or overhead service conductors shall not be attached to a service mast between a weatherhead or the end of the conduit and a coupling, where the coupling is located above the last point of securement to the building or other structure or is located above the building or other structure.

230.29 Supports over Buildings.

Service conductors passing over a roof shall be securely supported by substantial structures. For a grounded system, where the substantial structure is metal, it shall be bonded by means of a bonding jumper and listed connector to the grounded overhead service conductor. Where practicable, such supports shall be independent of the building.

Part III. Underground Service Conductors

230.30 Installation.

230.30(A) Insulation.

Underground service conductors shall be insulated for the applied voltage.

[!important] Exception: A grounded conductor shall be permitted to be uninsulated as follows:

• (1) Bare copper used in a raceway

• (2) Bare copper for direct burial where bare copper is approved for the soil conditions

• (3) Bare copper for direct burial without regard to soil conditions where part of a cable assembly identified for underground use

• (4) Aluminum or copper-clad aluminum without individual insulation or covering where part of a cable assembly identified for underground use in a raceway or for direct burial

230.30(B) Wiring Methods.

Underground service conductors shall be installed in accordance with the applicable requirements of this Code covering the type of wiring method used and shall be limited to the following methods:

• (1) Type RMC conduit

• (2) Type IMC conduit

• (3) Type NUCC conduit

• (4) Type HDPE conduit

• (5) Type PVC conduit

• (6) Type RTRC conduit

• (7) Type IGS cable

• (8) Type USE conductors or cables

• (9) Type MV or Type MC cable identified for direct burial applications

• (10) Type MI cable, where suitably protected against physical damage and corrosive conditions

230.31 Size and Ampacity.

230.31(A) General.

Underground service conductors shall have sufficient ampacity to carry the current for the load as calculated in accordance with Article 220 and shall have adequate mechanical strength.

230.31(B) Minimum Size.

The conductors shall not be smaller than 8 AWG copper or 6 AWG aluminum or copper-clad aluminum.

[!important] Exception: Conductors supplying only limited loads of a single branch circuit --- such as small polyphase power, controlled water heaters, and similar loads --- shall not be smaller than 12 AWG copper or 10 AWG aluminum or copper-clad aluminum.

230.31(C) Grounded Conductors.

The grounded conductor shall not be less than the minimum size required by 250.24(C).

230.32 Protection Against Damage.

Underground service conductors shall be protected against damage in accordance with 300.5. Service conductors entering a building or other structure shall be installed in accordance with 230.6 or protected by a raceway wiring method identified in 230.43.

230.33 Spliced Conductors.

Service conductors shall be permitted to be spliced or tapped in accordance with 110.14, 300.5(E), 300.13, and 300.15.

Part IV. Service-Entrance Conductors

230.40 Number of Service-Entrance Conductor Sets.

Each service drop, set of overhead service conductors, set of underground service conductors, or service lateral shall supply only one set of service-entrance conductors.

[!important] Exception No. 1: ^40e1 A building with more than one occupancy shall be permitted to have one set of service-entrance conductors for each service, as permitted in 230.2, run to each occupancy or group of occupancies. If the number of service disconnect locations for any given classification of service does not exceed six, the requirements of 230.2(E) shall apply at each location. If the number of service disconnect locations exceeds six for any given supply classification, all service disconnect locations for all supply characteristics, together with any branch circuit or feeder supply sources, if applicable, shall be clearly described using graphics or text, or both, on one or more plaques located in an approved, readily accessible location(s) on the building or structure served and as near as practicable to the point(s) of attachment or entry(ies) for each service drop or service lateral and for each set of overhead or underground service conductors.

[!important] Exception No. 2: ^40e2 Where two to six service disconnecting means in separate enclosures are grouped at one location and supply separate loads from one service drop, set of overhead service conductors, set of underground service conductors, or service lateral, one set of service-entrance conductors shall be permitted to supply each or several such service equipment enclosures.

[!important] Exception No. 3: ^40e3 A one-family dwelling unit and its accessory structures shall be permitted to have one set of service-entrance conductors run to each from a single service drop, set of overhead service conductors, set of underground service conductors, or service lateral.

[!important] Exception No. 4: ^40e4 Two-family dwellings, multifamily dwellings, and multiple occupancy buildings shall be permitted to have one set of service-entrance conductors installed to supply the circuits covered in 210.25.

[!important] Exception No. 5: ^40e5 One set of service-entrance conductors connected to the supply side of the normal service disconnecting means shall be permitted to supply each or several systems covered by 230.82(5) or 230.82(6).

230.41 Insulation of Service-Entrance Conductors.

Service-entrance conductors entering or on the exterior of buildings or other structures shall be insulated.

[!important] Exception: ^41e A grounded conductor shall be permitted to be uninsulated as follows:

• (1) Bare copper used in a raceway or part of a service cable assembly
• (2) Bare copper for direct burial where bare copper is approved for the soil conditions
• (3) Bare copper for direct burial without regard to soil conditions where part of a cable assembly identified for underground use
• (4) Aluminum or copper-clad aluminum without individual insulation or covering where part of a cable assembly or identified for underground use in a raceway, or for direct burial
• (5) Bare conductors used in an auxiliary gutter

230.42 Minimum Size and Ampacity.

230.42(A) General.

Service-entrance conductors shall have an ampacity of not less than the maximum load to be served. Conductors shall be sized not less than the largest of 230.42(A)(1) or (A)(2). Loads shall be determined in accordance with Part III, IV, or V of Article 220, as applicable. Ampacity shall be determined from 310.14 and shall comply with 110.14(C). The maximum current of busways shall be that value for which the busway has been listed or labeled.

[!info] Informational Note: For information on busways, see UL 857, Standard for Safety for Busways.

• (1) Where the service-entrance conductors supply continuous loads or any combination of noncontinuous and continuous loads, the minimum service-entrance conductor size shall have an ampacity not less than the sum of the noncontinuous loads plus 125 percent of continuous loads.

  [!important] Exception No. 1: Grounded conductors that are not connected to an overcurrent device shall be permitted to be sized at 100 percent of the sum of the continuous and noncontinuous load.

  [!important] Exception No. 2: The sum of the noncontinuous load and the continuous load if the service-entrance conductors terminate in an overcurrent device where both the overcurrent device and its assembly are listed for operation at 100 percent of their rating shall be permitted.

• (2) The minimum service-entrance conductor size shall have an ampacity not less than the maximum load to be served after the application of any adjustment or correction factors.

230.42(B) Specific Installations.

In addition to the requirements of 230.42(A), the minimum ampacity for ungrounded conductors for specific installations shall not be less than the rating of the service disconnecting means specified in 230.79(A) through (D).

230.42(C) Grounded Conductors.

The grounded conductor shall not be smaller than the minimum size as required by 250.24(C).

230.43 Wiring Methods for 1000 Volts, Nominal, or Less.

Service-entrance conductors shall be installed in accordance with the applicable requirements of this Code covering the type of wiring method used and shall be limited to the following methods:

• (1) Open wiring on insulators

• (2) Type IGS cable

• (3) Rigid metal conduit (RMC)

• (4) Intermediate metal conduit (IMC)

• (5) Electrical metallic tubing (EMT)

• (6) Electrical nonmetallic tubing

• (7) Service-entrance cables

• (8) Wireways

• (9) Busways

• (10) Auxiliary gutters

• (11) Rigid polyvinyl chloride conduit (PVC)

• (12) Cablebus

• (13) Type MC cable

• (14) Mineral-insulated, metal-sheathed cable, Type MI

• (15) Flexible metal conduit (FMC) not over 1.8 m (6 ft) long or liquidtight flexible metal conduit (LFMC) not over 1.8 m (6 ft) long between a raceway, or between a raceway and service equipment, with a supply-side bonding jumper routed with the flexible metal conduit (FMC) or the liquidtight flexible metal conduit (LFMC) according to 250.102(A), (B), (C), and (E)

• (16) Liquidtight flexible nonmetallic conduit (LFNC)

• (17) High density polyethylene conduit (HDPE)

• (18) Nonmetallic underground conduit with conductors (NUCC)

• (19) Reinforced thermosetting resin conduit (RTRC)

• (20) Type TC-ER cable

230.44 Cable Trays.

Cable tray systems shall be permitted to support service-entrance conductors. Cable trays used to support service-entrance conductors shall contain only service-entrance conductors and shall be limited to the following methods:

• (1) Type SE cable

• (2) Type MC cable

• (3) Type MI cable

• (4) Type IGS cable

• (5) Single conductors 1/0 and larger that are listed for use in cable tray

• (6) Type TC-ER cable

Such cable trays shall be identified with permanently affixed labels with the wording "Service-Entrance Conductors." The labels shall be located so as to be visible after installation with a spacing not to exceed 3 m (10 ft) so that the service-entrance conductors are able to be readily traced through the entire length of the cable tray.

[!important] Exception: Conductors, other than service-entrance conductors, shall be permitted to be installed in a cable tray with service-entrance conductors, provided a solid fixed barrier of a material compatible with the cable tray is installed to separate the service-entrance conductors from other conductors installed in the cable tray.

230.46 Spliced and Tapped Conductors.

Service-entrance conductors shall be permitted to be spliced or tapped in accordance with 110.14, 300.5(E), 300.13, and 300.15.

Power distribution blocks, pressure connectors, and devices for splices and taps shall be listed. Power distribution blocks installed on service conductors shall be marked "suitable for use on the line side of the service equipment" or equivalent.

Effective January 1, 2023, pressure connectors and devices for splices and taps installed on service conductors shall be marked "suitable for use on the line side of the service equipment" or equivalent.

230.50 Protection Against Physical Damage.

230.50(A) Underground Service-Entrance Conductors.

Underground service-entrance conductors shall be protected against physical damage in accordance with 300.5.

230.50(B) All Other Service-Entrance Conductors.

All other service-entrance conductors, other than underground service entrance conductors, shall be protected against physical damage as specified in 230.50(B)(1) or (B)(2).

230.50(B)(1) Service-Entrance Cables.

Service-entrance cables, where subject to physical damage, shall be protected by any of the following:

• (1) Rigid metal conduit (RMC)

• (2) Intermediate metal conduit (IMC)

• (3) Schedule 80 PVC conduit

• (4) Electrical metallic tubing (EMT)

• (5) Reinforced thermosetting resin conduit (RTRC)

• (6) Other approved means

230.50(B)(2) Other Than Service-Entrance Cables.

Individual open conductors and cables, other than service-entrance cables, shall not be installed within 3.0 m (10 ft) of grade level or where exposed to physical damage.

[!important] Exception: Type MI and Type MC cable shall be permitted within 3.0 m (10 ft) of grade level where not exposed to physical damage or where protected in accordance with 300.5(D).

230.51 Mounting Supports.

Service-entrance cables or individual open service-entrance conductors shall be supported as specified in 230.51(A), (B), or (C).

230.51(A) Service-Entrance Cables.

Service-entrance cables shall be supported by straps or other approved means within 300 mm (12 in.) of every service head, gooseneck, or connection to a raceway or enclosure and at intervals not exceeding 750 mm (30 in.).

230.51(B) Other Cables.

Cables that are not approved for mounting in contact with a building or other structure shall be mounted on insulating supports installed at intervals not exceeding 4.5 m (15 ft) and in a manner that maintains a clearance of not less than 50 mm (2 in.) from the surface over which they pass.

230.51(C) Individual Open Conductors.

Individual open conductors shall be installed in accordance with Table 230.51(C). Where exposed to the weather, the conductors shall be mounted on insulators or on insulating supports attached to racks, brackets, or other approved means. Where not exposed to the weather, the conductors shall be mounted on glass or porcelain knobs.

Table 230.51(C) Supports

Maximum Volts	Maximum Distance Between Supports	Minimum Clearance Between Conductors	Minimum Clearance From Surface
1000	2.7 m (9 ft)	150 mm (6 in.)	50 mm (2 in.)
1000	4.5 m (15 ft)	300 mm (12 in.)	50 mm (2 in.)
300	1.4 m (4 1/2 ft)	75 mm (3 in.)	50 mm (2 in.)
1000*	1.4 m (4 1/2 ft)	65 mm (2 1/2 in.)	25 mm (1 in.)

*Where not exposed to weather.

230.52 Individual Conductors Entering Buildings or Other Structures.

Where individual open conductors enter a building or other structure, they shall enter through roof bushings or through the wall in an upward slant through individual, noncombustible, nonabsorbent insulating tubes. Drip loops shall be formed on the conductors before they enter the tubes.

230.53 Raceways to Drain.

Where exposed to the weather, raceways enclosing service-entrance conductors shall be listed or approved for use in wet locations and arranged to drain. Where embedded in masonry, raceways shall be arranged to drain.

230.54 Overhead Service Locations.

230.54(A) Service Head.

Service raceways shall be equipped with a service head at the point of connection to service-drop or overhead service conductors. The service head shall be listed for use in wet locations.

230.54(B) Service-Entrance Cables Equipped with Service Head or Gooseneck.

Service-entrance cables shall be equipped with a service head. The service head shall be listed for use in wet locations.

[!important] Exception: Type SE cable shall be permitted to be formed in a gooseneck and taped with a self-sealing weather-resistant thermoplastic.

230.54(C) Service Heads and Goosenecks Above Service-Drop or Overhead Service Attachment.

Service heads on raceways or service-entrance cables and goosenecks in service-entrance cables shall be located above the point of attachment of the service-drop or overhead service conductors to the building or other structure.

[!important] Exception: Where it is impracticable to locate the service head or gooseneck above the point of attachment, the service head or gooseneck location shall be permitted not farther than 600 mm (24 in.) from the point of attachment.

230.54(D) Secured.

Service-entrance cables shall be held securely in place.

230.54(E) Separately Bushed Openings.

Service heads shall have conductors of different potential brought out through separately bushed openings.

[!important] Exception: For jacketed multiconductor service-entrance cable without splice.

230.54(F) Drip Loops.

Drip loops shall be formed on individual conductors. To prevent the entrance of moisture, service-entrance conductors shall be connected to the service-drop or overhead service conductors either (1) below the level of the service head or (2) below the level of the termination of the service-entrance cable sheath.

230.54(G) Arranged That Water Will Not Enter Service Raceway or Equipment.

Service-entrance and overhead service conductors shall be arranged so that water will not enter service raceway or equipment.

230.56 Service Conductor with the Higher Voltage to Ground.

On a 4-wire, delta-connected service where the midpoint of one phase winding is grounded, the service conductor having the higher phase voltage to ground shall be durably and permanently marked by an outer finish that is orange in color, or by other effective means, at each termination or junction point.

Part V. Service Equipment --- General

230.62 Service Equipment --- Enclosed or Guarded.

Energized parts of service equipment shall be enclosed as specified in 230.62(A) or guarded as specified in 230.62(B).

230.62(A) Enclosed.

Energized parts shall be enclosed so that they will not be exposed to accidental contact or shall be guarded as in 230.62(B).

230.62(B) Guarded.

Energized parts that are not enclosed shall be installed on a switchboard, panelboard, or control board and guarded in accordance with 110.18 and 110.27. Where energized parts are guarded as provided in 110.27(A)(1) and (A) (2), a means for locking or sealing doors providing access to energized parts shall be provided.

230.62(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.

230.66 Marking.

230.66(A) General.

Service equipment rated at 1000 volts or less shall be marked to identify it as being suitable for use as service equipment. All service equipment shall be listed or field evaluated.

230.66(B) Meter Sockets.

Meter sockets shall not be considered service equipment but shall be listed and rated for the voltage and current rating of the service.

[!important] Exception: Meter sockets supplied by and under the exclusive control of an electric utility shall not be required to be listed.

230.67 Surge Protection.

230.67(A) Surge-Protective Device.

All services supplying dwelling units shall be provided with a surge-protective device (SPD).

230.67(B) Location.

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

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

230.67(C) Type.

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

230.67(D) Replacement.

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

Part VI. Service Equipment --- Disconnecting Means

230.70 General.

Means shall be provided to disconnect all ungrounded conductors in a building or other structure from the service conductors.

230.70(A) Location.

The service disconnecting means shall be instal led in accordance with 230.70(A)(1), (A)(2), and (A)(3).

230.70(A)(1) Readily Accessible Location.

The service disconnecting means shall be installed at a readily accessible location either outside of a building or structure or inside nearest the point of entrance of the service conductors.

230.70(A)(2) Bathrooms.

Service disconnecting means shall not be installed in bathrooms.

230.70(A)(3) Remote Control.

Where a remote control device(s) is used to actuate the service disconnecting means, the service disconnecting means shall be located in accordance with 230.70(A) (1).

230.70(B) Marking.

Each service disconnect shall be permanently marked to identify it as a service disconnect.

230.70(C) Suitable for Use.

Each service disconnecting means shall be suitable for the prevailing conditions. Service equipment installed in hazardous (classified) locations shall comply with the requirements of Articles 500 through 517.

230.71 Maximum Number of Disconnects.

Each service shall have only one disconnecting means unless the requirements of 230.71(B) are met.

230.71(A) General.

For the purpose of this section, disconnecting means installed as part of listed equipment and used solely for the following shall not be considered a service disconnecting means:

• (1) Power monitoring equipment

• (2) Surge-protective device(s)

• (3) Control circuit of the ground-fault protection system

• (4) Power-operable service disconnecting means

230.71(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

• (4) Service disconnects in switchgear or metering centers where each disconnect is located in a separate compartment

[!info] Informational Note No. 1: Metering centers are addressed in UL 67, Standard for Panelboards.

[!info] 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, circuit breaker enclosures, and transfer switches that are suitable for use as service equipment.

230.72 Grouping of Disconnects.

230.72(A) General.

The two to six disconnects, if permitted in 230.71, shall be grouped. Each disconnect shall be marked to indicate the load served.

[!important] Exception: One of the two to six service disconnecting means permitted in 230.71, where used only for a water pump also intended to provide fire protection, shall be permitted to be located remote from the other disconnecting means. If remotely installed in accordance with this exception, a plaque shall be posted at the location of the remaining grouped disconnects denoting its location.

230.72(B) Additional Service Disconnecting Means.

The one or more additional service disconnecting means for fire pumps, emergency systems, legally required standby, or optional standby services permitted by 230.2 shall be installed remote from the one to six service disconnecting means for normal service to minimize the possibility of simultaneous interruption of supply.

230.72(C) Access to Occupants.

In a multiple-occupancy building, each occupant shall have access to the occupant's service disconnecting means.

[!important] Exception: In a multiple-occupancy building where electric service and electrical maintenance are provided by the building management and where these are under continuous building management supervision, the service disconnecting means supplying more than one occupancy shall be permitted to be accessible to authorized management personnel only.

230.74 Simultaneous Opening of Poles.

Each service disconnect shall simultaneously disconnect all ungrounded service conductors that it controls from the premises wiring system.

230.75 Disconnection of Grounded Conductor.

Where the service disconnecting means does not disconnect the grounded conductor from the premises wiring, other means shall be provided for this purpose in the service equipment. A terminal or bus to which all grounded conductors can be attached by means of pressure connectors shall be permitted for this purpose. In a multisection switchboard or switchgear, disconnects for the grounded conductor shall be permitted to be in any section of the switchboard or switchgear.

[!info] Informational Note: In switchgear or multisection switchboards, the disconnecting means provided for the grounded conductor is typically identified as a neutral disconnect link and is typically located in the bus to which the service grounded conductor is connected.

230.76 Manually or Power Operable.

The service disconnecting means for ungrounded service conductors shall consist of one of the following:

• (1) A manually operable switch or circuit breaker equipped with a handle or other suitable operating means

• (2) A power-operated switch or circuit breaker, provided the switch or circuit breaker can be opened by hand in the event of a power supply failure

230.77 Indicating.

The service disconnecting means shall plainly indicate whether it is in the open (off) or closed (on) position.

230.79 Rating of Service Disconnecting Means.

The service disconnecting means shall have a rating not less than the calculated load to be carried, determined in accordance with

Part III, IV, or V of Article 220, as applicable. In no case shall the rating be lower than specified in 230.79(A), (B), (C), or (D).

230.79(A) One-Circuit Installations.

For installations to supply only limited loads of a single branch circuit, the service disconnecting means shall have a rating of not less than 15 amperes.

230.79(B) Two-Circuit Installations.

For installations consisting of not more than two 2-wire branch circuits, the service disconnecting means shall have a rating of not less than 30 amperes.

230.79(C) One-Family Dwellings.

For a one-family dwelling, the service disconnecting means shall have a rating of not less than 100 amperes, 3-wire.

230.79(D) All Others.

For all other installations, the service disconnecting means shall have a rating of not less than 60 amperes.

230.80 Combined Rating of Disconnects.

Where the service disconnecting means consists of more than one switch or circuit breaker, as permitted by 230.71, the combined ratings of all the switches or circuit breakers used shall not be less than the rating required by 230.79.

230.81 Connection to Terminals.

The service conductors shall be connected to the service disconnecting means by pressure connectors, clamps, or other approved means. Connections that depend on solder shall not be used.

230.82 Equipment Connected to the Supply Side of Service Disconnect.

Only the following equipment shall be permitted to be connected to the supply side of the service disconnecting means:

• (1) Cable limiters.

• (2) Meters and meter sockets nominally rated not in excess of 1000 volts, if all metal housings and service enclosures are grounded in accordance with Part VII and bonded in accordance with Part V of Article 250.

• (3) Meter disconnect switches nominally rated not in excess of 1000 volts that have a short-circuit current rating equal to or greater than the available fault current, if all metal housings and service enclosures are grounded in accordance with Part VII and bonded in accordance with Part V of Article 250. A meter disconnect switch shall be capable of interrupting the load served. A meter disconnect shall be legibly field marked on its exterior in a manner suitable for the environment as follows:

  METER DISCONNECT
  NOT SERVICE EQUIPMENT
  

• (4) Instrument transformers (current and voltage), impedance shunts, load management devices, surge arresters, and Type 1 surge-protective devices.

• (5) Conductors used to supply load management devices, circuits for standby power systems, fire pump equipment, and fire and sprinkler alarms, if provided with service equipment and installed in accordance with requirements for service-entrance conductors.

• (6) Solar photovoltaic systems, fuel cell systems, wind electric systems, energy storage systems, or interconnected electric power production sources, if provided with a disconnecting means listed as suitable for use as service equipment, and overcurrent protection as specified in Part VII of Article 230.

• (7) Control circuits for power-operable service disconnecting means, if suitable overcurrent protection and disconnecting means are provided.

• (8) Ground-fault protection systems or Type 2 surge-protective devices, where installed as part of listed equipment, if suitable overcurrent protection and disconnecting means are provided.

• (9) Connections used only to supply listed communications equipment under the exclusive control of the serving electric utility, if suitable overcurrent protection and disconnecting means are provided. For installations of equipment by the serving electric utility, a disconnecting means is not required if the supply is installed as part of a meter socket, such that access can only be gained with the meter removed.

• (10) Emergency disconnects in accordance with 230.85, if all metal housings and service enclosures are grounded in accordance with Part VII and bonded in accordance with Part V of Article 250.

• (11) Meter-mounted transfer switches nominally rated not in excess of 1000 volts that have a short-circuit current rating equal to or greater than the available fault current. A meter-mounted transfer switch shall be listed and be capable of transferring the load served. A meter-mounted transfer switch shall be marked on its exterior with both of the following:

  • a. Meter-mounted transfer switch
  • b. Not service equipment

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:

• (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
  

Markings shall comply with 110.21(B).

Part VII. Service Equipment --- Overcurrent Protection

230.90 Where Required.

Each ungrounded service conductor shall have overload protection.

230.90(A) Ungrounded Conductor.

Such protection shall be provided by an overcurrent device in series with each ungrounded service conductor that has a rating or setting not higher than the ampacity of the conductor. A set of fuses shall be considered all the fuses required to protect all the ungrounded conductors of a circuit. Single-pole circuit breakers, grouped in accordance with 230.71(B), shall be considered as one protective device.

[!important] Exception No. 1: For motor-starting currents, ratings that comply with 430.52, 430.62, and 430.63 shall be permitted.

[!important] Exception No. 2: Fuses and circuit breakers with a rating or setting that complies with 240.4(B) or (C) and 240.6 shall be permitted.

[!important] Exception No. 3: Two to six circuit breakers or sets of fuses shall be permitted as the overcurrent device to provide the overload protection. The sum of the ratings of the circuit breakers or fuses shall be permitted to exceed the ampacity of the service conductors, provided the calculated load does not exceed the ampacity of the service conductors.

[!important] Exception No. 4: Overload protection for fire pump supply conductors shall comply with 695.4(B)(2)(a).

[!important] Exception No. 5: Overload protection for 120/240-volt, 3-wire, single-phase dwelling services shall be permitted in accordance with the requirements of 310.12.

230.90(B) Not in Grounded Conductor.

No overcurrent device shall be inserted in a grounded service conductor except a circuit breaker that simultaneously opens all conductors of the circuit.

230.91 Location.

The service overcurrent device shall be an integral part of the service disconnecting means or shall be located immediately adjacent thereto. Where fuses are used as the service overcurrent device, the disconnecting means shall be located ahead of the supply side of the fuses.

230.92 Locked Service Overcurrent Devices.

Where the service overcurrent devices are locked or sealed or are not readily accessible to the occupant, branch-circuit or feeder overcurrent devices shall be installed on the load side, shall be mounted in a readily accessible location, and shall be of lower ampere rating than the service overcurrent device.

230.93 Protection of Specific Circuits.

Where necessary to prevent tampering, an automatic overcurrent device that protects service conductors supplying only a specific load, such as a water heater, shall be permitted to be locked or sealed where located so as to be accessible.

230.94 Relative Location of Overcurrent Device and Other Service Equipment.

The overcurrent device shall protect all circuits and devices.

[!important] Exception No. 1: The service switch shall be permitted on the supply side.

[!important] Exception No. 2: High-impedance shunt circuits, surge arresters, Type 1 surge-protective devices, surge-protective capacitors, and instrument transformers (current and voltage) shall be permitted to be connected and installed on the supply side of the service disconnecting means as permitted by 230.82.

[!important] Exception No. 3: Circuits for load management devices shall be permitted to be connected on the supply side of the service overcurrent device where separately provided with overcurrent protection.

[!important] Exception No. 4: Circuits used only for the operation of fire alarm, other protective signaling systems, or the supply to fire pump equipment shall be permitted to be connected on the supply side of the service overcurrent device where separately provided with overcurrent protection.

[!important] Exception No. 5: Meters nominally rated not in excess of 600 volts shall be permitted, provided all metal housings and service enclosures are grounded.

[!important] Exception No. 6: Where service equipment is power operable, the control circuit shall be permitted to be connected ahead of the service equipment if suitable overcurrent protection and disconnecting means are provided.

230.95 Ground-Fault Protection of Equipment.

Ground-fault protection of equipment shall be provided for solidly grounded wye electric services of more than 150 volts to ground but not exceeding 1000 volts phase-to-phase for each service disconnect rated 1000 amperes or more. The grounded conductor for the solidly grounded wye system shall be connected directly to ground through a grounding electrode system, as specified in 250.50, without inserting any resistor or impedance device.

The rating of the service disconnect shall be considered to be the rating of the largest fuse that can be installed or the highest continuous current trip setting for which the actual overcurrent device installed in a circuit breaker is rated or can be adjusted.

[!important] Exception: The ground-fault protection provisions of this section shall not apply to a service disconnect for a continuous industrial process where a nonorderly shutdown will introduce additional or increased hazards.

230.95(A) Setting.

The ground-fault protection system shall operate to cause the service disconnect to open all ungrounded conductors of the faulted circuit. The maximum setting of the ground-fault protection shall be 1200 amperes, and the maximum time delay shall be one second for ground-fault currents equal to or greater than 3000 amperes.

230.95(B) Fuses.

If a switch and fuse combination is used, the fuses employed shall be capable of interrupting any current higher than the interrupting capacity of the switch during a time that the ground-fault protective system will not cause the switch to open.

230.95(C) Performance Testing.

The ground-fault protection system shall be performance tested when first installed on site. This testing shall be conducted by a qualified person(s) using a test process of primary current injection, in accordance with instructions that shall be provided with the equipment. A written record of this testing shall be made and shall be available to the authority having jurisdiction.

[!info] Informational Note No. 1: Ground-fault protection that functions to open the service disconnect affords no protection from faults on the line side of the protective element. It serves only to limit damage to conductors and equipment on the load side in the event of an arcing ground fault on the load side of the protective element.

[!info] Informational Note No. 2: This added protective equipment at the service equipment may make it necessary to review the overall wiring system for proper selective overcurrent protection coordination. Additional installations of ground-fault protective equipment may be needed on feeders and branch circuits where maximum continuity of electric service is necessary.

[!info] Informational Note No. 3: Where ground-fault protection is provided for the service disconnect and interconnection is made with another supply system by a transfer device, means or devices may be needed to ensure proper ground-fault sensing by the ground-fault protection equipment.

[!info] Informational Note No. 4: See 517.17(A) for information on where an additional step of ground-fault protection is required for hospitals and other buildings with critical areas or life support equipment.

Part VIII. Services Exceeding 1000 Volts, Nominal

230.200 General.

Service conductors and equipment used on circuits exceeding 1000 volts, nominal, shall comply with all the applicable preceding sections of this article and with the following sections that supplement or modify the preceding sections. In no case shall the provisions of Part VIII apply to equipment on the supply side of the service point.

[!info] Informational Note: For clearances of conductors of over 1000 volts, nominal, see ANSI/IEEE C2-2017, National Electrical Safety Code.

230.202 Service-Entrance Conductors.

Service-entrance conductors to buildings or enclosures shall be installed to conform to 230.202(A) and (B).

230.202(A) Conductor Size.

Service-entrance conductors shall not be smaller than 6 AWG unless in multiconductor cable. Multiconductor cable shall not be smaller than 8 AWG.

230.202(B) Wiring Methods.

Service-entrance conductors shall be installed by one of the wiring methods covered in 300.37 and 300.50.

230.204 Isolating Switches.

230.204(A) Where Required.

Where oil switches or air, oil, vacuum, or sulfur hexafluoride circuit breakers constitute the service disconnecting means, an isolating switch with visible break contacts shall be installed on the supply side of the disconnecting means and all associated service equipment.

[!important] Exception: An isolating switch shall not be required where the circuit breaker or switch is mounted on removable truck panels or switchgear units where both of the following conditions apply:

• (1) Cannot be opened unless the circuit is disconnected

• (2) Where all energized parts are automatically disconnected when the circuit breaker or switch is removed from the normal operating position

230.204(B) Fuses as Isolating Switch.

Where fuses are of the type that can be operated as a disconnecting switch, a set of such fuses shall be permitted as the isolating switch.

230.204(C) Accessible to Qualified Persons Only.

The isolating switch shall be accessible to qualified persons only.

230.204(D) Connection to Ground.

Isolating switches shall be provided with a means for readily connecting the load side conductors to a grounding electrode system, equipment ground busbar, or grounded steel structure when disconnected from the source of supply.

A means for grounding the load side conductors to a grounding electrode system, equipment grounding busbar, or grounded structural steel shall not be required for any duplicate isolating switch installed and maintained by the electric supply company.

230.205 Disconnecting Means.

230.205(A) Location.

The service disconnecting means shall be located in accordance with 230.70.

For either overhead or underground primary distribution systems on private property, the service disconnect shall be permitted to be located in a location that is not readily accessible, if the disconnecting means can be operated by mechanical linkage from a readily accessible point, or electronically in accordance with 230.205(C), where applicable.

230.205(B) Type.

Each service disconnect shall simultaneously disconnect all ungrounded service conductors that it controls and shall have a faultclosing rating that is not less than the available fault current at its supply terminals.

Where fused switches or separately mounted fuses are instal led, the fuse characteristics shall be permitted to contribute to the faultclosing rating of the disconnecting means.

230.205(C) Remote Control.

For multibuilding, industrial installations under single management, the service disconnecting means shall be permitted to be located at a separate building or structure. In such cases, the service disconnecting means shall be permitted to be electrically operated by a readily accessible, remote-control device.

230.206 Overcurrent Devices as Disconnecting Means.

Where the circuit breaker or alternative for it, as specified in 230.208 for service overcurrent devices, meets the requirements specified in 230.205, it shall constitute the service disconnecting means.

230.208 Protection Requirements.

A short-circuit protective device shall be provided on the load side of, or as an integral part of, the service disconnect, and shall protect all ungrounded conductors that it supplies. The protective device shall be capable of detecting and interrupting all values of current, in excess of its trip setting or melting point, that can occur at its location. A fuse rated in continuous amperes not to exceed three times the ampacity of the conductor, or a circuit breaker with a trip setting of not more than six times the ampacity of the conductors, shall be considered as providing the required short-circuit protection.

[!info] Informational Note: See Table 311.60(C)(67) through Table 311.60(C)(86) for ampacities of conductors rated 2001 volts to 35,000 volts.

Overcurrent devices shall conform to 230.208(A) and (B).

230.208(A) Equipment Type.

Equipment used to protect service-entrance conductors shall meet the requirements of Article 490, Part II.

230.208(B) Enclosed Overcurrent Devices.

The restriction to 80 percent of the rating for an enclosed overcurrent device for continuous loads shall not apply to overcurrent devices instal led in systems operating at over 1000 volts.

230.209 Surge Arresters.

Surge arresters installed in accordance with the requirements of Article 242 shall be permitted on each ungrounded overhead service conductor.

[!info] Informational Note: Surge arresters may be referred to as lightning arresters in older documents.

230.210 Service Equipment --- General Provisions.

Service equipment, including instrument transformers, shall conform to Article 490, Part I.

230.211 Switchgear.

Switchgear shall consist of a substantial metal structure and a sheet metal enclosure. Where installed over a combustible floor, suitable protection thereto shall be provided.

230.212 Over 35,000 Volts.

Where the voltage exceeds 35,000 volts between conductors that enter a building, they shall terminate in a switchgear compartment or a vault conforming to the requirements of 450.41 through 450.48.