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ture. ENHANCED CONTENT Collapse This requirement correlates with 230.2(E) in that, if a building has multiple sources of supply, permanent identification at each supply (service, feeder, and branch circuit) disconnecting means is required. Permanent identification must have long-term durability. Suc...

ture. ENHANCED CONTENT Collapse This requirement correlates with 230.2(E) in that, if a building has multiple sources of supply, permanent identification at each supply (service, feeder, and branch circuit) disconnecting means is required. Permanent identification must have long-term durability. Such identification is an important safety feature during an emergency, because in many cases first responders will not be familiar with the electrical distribution system of the facility. See also… * 700.7(A) for emergency power sources * 701.7(A) for legally required standby sources * 702.7(A) for optional standby sources * 705.10 for parallel power production sources * 706.21 for energy storage systems (ESS) * 710.10 for stand-alone systems 225.38 Disconnect Construction. Disconnecting means shall meet the requirements of 225.38(A) through (D). (A) Manually or Power Operable. The disconnecting means shall consist of either (1) a manually operable switch or a circuit breaker equipped with a handle or other suitable operating means or (2) a power- operable switch or circuit breaker, provided the switch or circuit breaker can be opened by hand in the event of a power failure. (B) Simultaneous Opening of Poles. Each building or structure disconnecting means shall simultaneously disconnect all ungrounded supply conductors that it controls from the building or structure wiring system. (C) Disconnection of Grounded Conductor. Where the building or structure disconnecting means does not disconnect the grounded conductor from the grounded conductors in the building or structure wiring, other means shall be provided for this purpose at the location of the disconnecting means. 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, if the switchboard section or switchgear section is marked to indicate a grounded conductor disconnect is contained within the equipment. (D) Indicating. The building or structure disconnecting means shall plainly indicate whether it is in the open or closed position. 225.39 Rating of Disconnect. The feeder or branch-circuit disconnecting means shall have a rating of not less than the calculated load to be supplied, determined in accordance with Parts I and II of Article 220 for branch circuits, Part III or IV of Article 220 for feeders, or Part V of Article 220 for farm loads. Where the branch circuit or feeder disconnecting means consists of more than one switch or circuit breaker, as permitted by 225.33, combining the ratings of all the switches or circuit breakers for determining the rating of the disconnecting means shall be permitted. In no case shall the rating be lower than specified in 225.39(A), (B), (C), or (D). (A) One-Circuit Installation. For installations to supply only limited loads of a single branch circuit, the branch circuit disconnecting means shall have a rating of not less than 15 amperes. (B) Two-Circuit Installations. For installations consisting of not more than two 2-wire branch circuits, the feeder or branch-circuit disconnecting means shall have a rating of not less than 30 amperes. (C) One-Family Dwelling. For a one-family dwelling, the feeder disconnecting means shall have a rating of not less than 100 amperes, 3-wire. (D) All Others. For all other installations, the feeder or branch-circuit disconnecting means shall have a rating of not less than 60 amperes. 225.40 Access to Overcurrent Protective Devices. Where a feeder overcurrent device is not readily accessible, branch-circuit overcurrent devices shall be installed on the load side, shall be mounted in a readily accessible location, and shall be of a lower ampere rating than the feeder overcurrent device. 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 Isolation Disconnects. Where equipment for isolation of other energy source systems is not located adjacent to the emergency disconnect required by this section, a plaque or directory identifying the location of all equipment for isolation of other energy sources shall be located adjacent to the disconnecting means required by this section. Informational Note: See 445.18, 480.7, 705.20, and 706.15 for examples of other energy source system isolation means. (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. * (2) The letters shall be least 13 mm (1/2 in.) high. 225.42 Surge Protection. (A) Surge-Protective Device. Where a feeder supplies any of the following, a surge-protective device (SPD) shall be installed: * (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 (B) Location. The SPD shall be installed in or adjacent to the distribution equipment that is connected to the load side of the feeder and contains branch circuit overcurrent protective device(s) that supply the location specified in 225.42(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. Article 230 Services Part I. General 230.1 Scope. This article covers service conductors and equipment for control and protection of services not over 1000 volts ac or 1500 volts dc, nominal and their installation requirements. Informational Note No. 1: See Informational Note Figure 230.1. Informational Note Figure 230.1 Services. Informational Note No. 2: See Part V of Article 235 for services over 1000 volts ac or 1500 volts dc, nominal. 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 230.40, Exception No. 2 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. ENHANCED CONTENT Collapse The general requirement is for a building or structure to be supplied by only one service. However, under some conditions, a single service might not be adequate. Therefore, the installation of additional services is permitted as specified in conditions covered by 230.2(A) through (D). Where more than one service (or combination of service, feeder, and branch circuit) is installed, 230.2(E) requires that a permanent plaque or directory with the pertinent information on the multiple sources of supply be located at each supply source disconnecting means. The exhibits that follow illustrate examples of the general requirement that a building or structure be supplied by only one service. The exhibit below shows an example of a building having one service drop or one set of overhead service conductors supplying six separate disconnects in separate compartments. The building has more than one occupancy with separate loads by the single service, in accordance with 230.2 and 230.71. The next exhibit illustrates 0ne set of underground service conductors consisting of six sets of conductors 1/0 AWG or larger (connected at their supply ends), terminating in six separate service equipment enclosures. The building has more than one occupancy. The separate loads are fed by one service lateral or one set of underground service conductors, in accordance with 230.2; 230.40, Exception No. 2; and 230.71. The exhibit below shows one service drop or one set of overhead service conductors supplying two service equipment enclosures installed at separate locations. The building has two groups of occupancies and two service equipment enclosures. The disconnecting means are in separate compartments within the enclosures. See 230.40, Exception No. 1, and 230.71. The following exhibit illustrates one set of overhead service conductors supplying a maximum of six separate service disconnecting means enclosures for a building having more than one occupancy. Separate loads are fed by one service, in accordance with 230.40, Exception No. 2, and 230.71. The next exhibit shows one set of underground service conductors supplying multiple service disconnecting means in separate compartments for a multi-occupancy building. Separate loads are supplied by one service, in accordance with 230.40, Exception No. 1, and 230.71. The final exhibit below shows four sets of service laterals supplying four service equipment enclosures installed at separate locations on a contiguous structure. Note the presence of firewalls, which make the structures separate buildings. Special Conditions. Additional services shall be permitted to supply the following: Fire pumps Emergency systems Legally required standby systems Optional standby systems Interconnected electric power production sources Systems designed for connection to multiple sources of supply for the purpose of enhanced reliability ENHANCED CONTENT Collapse Completely separate services to these systems and equipment increases the overall reliability of the power supply to these systems by negating the impact of a disruption of the main building service. Unless the separate service is supplied from a different utility circuit, no protection is provided against an overall utility system outage. However, the effect of an outage resulting from a problem between the service point and the ?normal,? or main, building service equipment will be limited to the normal service. Special Occupancies. By special permission, additional services shall be permitted for either of the following: Multiple-occupancy buildings where there is no available space for service equipment accessible to all occupants A single building or other structure sufficiently large to make two or more services necessary ENHANCED CONTENT Collapse Additional services for certain occupancies are allowed by special permission, that is, written consent of the AHJ. See the definition of authority having jurisdiction in Article The expansion of buildings often necessitates the addition of one or more services. It might be impractical or even impossible to install one service for an industrial plant with sufficient capacity for any and all future loads. It is also impractical to run extremely long feeders. The AHJ should be consulted early in the planning stages to ascertain whether special permission can be obtained. Capacity Requirements. Additional services shall be permitted under any of the following: Where the capacity requirements are in excess of 2000 amperes at a supply voltage of 1000 volts or less Where the load requirements of a single-phase installation are greater than the serving agency normally supplies through one service By special permission ENHANCED CONTENT Collapse If two or more services are needed, each service is not required be rated 2000 amperes or that there be one service rated 2000 amperes and the additional service(s) rated for the calculated load in excess of 2000 amperes. For example, a building with a calculated load of 2300 amperes could have two 1200-ampere services. Additional services for lesser loads also are allowed by special permission. Many electric utilities have specifications for, and enforce special regulations covering, certain types of electrical loads and service equipment. Before electrical services for large buildings and facilities are designed, the serving utility should be consulted to determine line and transformer capacities. The exhibits that follow illustrate examples of service configurations permitted by 230.2(B) and (C); 230.40, Exceptions No. 1 and No. 2; 230.71; and 230.72. The exhibits depict a number of service arrangements where more than a single service or multiple sets of service-entrance conductors are used to supply a building with one or more than one occupancy. The exhibits also illustrate the 230.71 requirement that not more than six service disconnecting means be grouped in one location; defining and determining the ?one location? is a matter for the AHJ. Additionally, a building can also be supplied by a feeder. This commonly occurs where the building is supplied with emergency, legally required standby, and/or optional standby power. Such installations are subject to the requirements of this article as well as Articles 225, 700, 701, and 702 as applicable. The exhibit below shows an example of one service drop or two sets of overhead service conductors supplying two services, installed at separate locations for a building with more than one occupancy where there is no available space for service equipment accessible to all occupants, in accordance with 230.2(B)(1) and 230.72(C). The next exhibit illustrates two service drops or two sets of overhead service conductors supplying two services, installed at separate locations for a building with capacity requirements exceeding 2000 amperes, in accordance with 230.2(C)(1) and 230.71. The following exhibit shows two sets of underground service conductors, terminating in two service equipment enclosures installed at separate locations. Separate loads are supplied by a separate service, in accordance with 230.2(B)(1) and 230.71. The exhibit below illustrates four sets of underground service conductors supplying four service equipment enclosures installed at different locations. There is more than one occupancy with separate loads supplied by four sets of underground service conductors, in accordance with 230.40, Exception No.1, and 230.71. Different Characteristics. Additional services shall be permitted for different voltages, frequencies, or phases, or for different uses, such as for different rate schedules. ENHANCED CONTENT Collapse An example of different service characteristics is a facility served by a 3-wire, 120/240- volt, single-phase service and a 3-phase, 4-wire, 480Y/277-volt service. Where rate schedules are different, a second service is permitted for supplying a second meter on a different rate. Curtailable loads, interruptible loads, electric heating, and electric water heating are examples of loads that may be on a different rate schedule. 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. ENHANCED CONTENT Collapse The permanent plaque or directory must indicate where the other disconnects that supply the building are located, as illustrated below. All the other services on or in the building or structure and the area served by each also must be noted on the plaques or directories. This information is critically important to first responders, maintenance staff, and other persons who need to disconnect the building or structure from all of its supplies. The plaques or directories must be of sufficient durability to withstand the environment and remain legible. 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. ENHANCED CONTENT Collapse Although service conductors that supply one building or structure are prohibited from being run through the interior of another building or structure, service conductors are permitted to be installed along the exterior of one building to supply another building. Each building served in this manner is required to be provided with a disconnecting means for all ungrounded conductors, in accordance with Part VI. For example, in the exhibit below, the disconnecting means suitable for use as service equipment is shown on the exterior walls of Building No. 1 and Building No. 2. The prohibition against passing through one building to another applies only to service conductors, because feeders and branch circuits are provided with overcurrent protection at the point they receive their supply unless otherwise permitted by 240.21. 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 Part III of Article 450 * (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 (RMC) or intermediate metal conduit (IMC) used to accommodate the clearance requirements in 230.24 and routed directly through an eave but not a wall of a building ENHANCED CONTENT Collapse The following exhibit illustrates two of the conditions that permit service conductors to be considered outside a building. Service conductors installed in an interior vault complying with the construction requirements of Part III of Article 450 are considered to be outside a building regardless of whether or not the vault contains a transformer. Once the conductors leave the vault, the service disconnecting means has to be installed as required by 230.70(A)(1). Service conductors installed in conduit and under 18 inches of earth beneath the building are also considered outside the building according to 230.6(4). An example of that would be a building or structure built on piers with service conductors buried beneath and running to a readily accessible service disconnecting means located within the interior of the building or structure. Service conductors passing through a roof overhang as covered in 230.24(A), Exception No. 3, are considered to be outside the building per 230.6(5). This requirement would not allow horizontal runs through eaves. 230.7 Other Conductors. Circuit conductors other than service conductors, shall not be installed in the same raceway, cable, handhole enclosure, or underground box as the service conductors. Exception No. 1: Grounding electrode conductors or supply side bonding jumpers or conductors shall be permitted within service raceways. Exception No. 2: Load management control conductors having overcurrent protection shall be permitted within service raceways. ENHANCED CONTENT Collapse Service conductors are not provided with overcurrent protection where they receive their supply; they are protected against overload conditions at their load end by the service disconnect fuses or circuit breakers. If feeder or branch-circuit conductors are in the same raceway with service conductors during a fault, the fault current that could flow through them would be much higher than the ampacity of the feeder or branch-circuit conductors. The gutter space of a panelboard cabinet or other electrical equipment enclosure is not a raceway as defined in Article 100 and is not subject to the requirement of 230.7. Service conductors, feeder conductors, and branch-circuit conductors can share the same gutter space. The panelboard cabinet gutter space accommodates a set of service conductors terminating on the 200-ampere main breaker, a set of feeder conductors supplying the adjacent panelboard, and several sets of branch circuit conductors entering the bottom of the cabinet that will connect to overcurrent protective devices (OCPDs) installed on the panelboard. 230.8 Raceway Seal. Where a service raceway enters a building or structure, it shall be sealed in accordance with 300.5(G) and 300.7(A). Spare or unused raceways shall also be sealed. Sealants shall be identified for use with the cable insulation, conductor insulation, bare conductor, shield, or other components. ENHANCED CONTENT Collapse Sealant, such as duct seal or a bushing incorporating the physical characteristics of a seal, is required to be used to seal the ends of service raceways. The intent is to prevent water ? usually the result of condensation due to temperature differences ? from entering the service equipment via the raceway. The sealant material should be compatible with the conductor insulation and should not cause deterioration of the insulation over time. 230.9 Clearances on Buildings. Service conductors and final spans shall comply with 230.9(A), (B), and (C). (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. Exception: Conductors run above the top level of a window shall be permitted to be less than the 900 mm (3 ft) requirement. ENHANCED CONTENT Collapse The 3-foot clearance applies to open conductors, not to a raceway or to a cable assembly that has an overall outer jacket, such as Types SE, MC, and MI cables. This distance protects the conductors from physical damage and persons from accidental contact with the conductors. The exception permits service conductors, including service-entrance conductors, overhead service conductors, and service-drop conductors, to be located just above window openings, because they are considered out of reach, as illustrated in the exhibit below. 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). ENHANCED CONTENT Collapse Service conductors must not be located where a person could reach and touch them. The amount of vertical clearance required depends on the location and voltage of the overhead conductors. The following exhibit illustrates an installation where the 10-foot clearance is based on the conditions described in 230.24(B)(1). 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. Exception: The grounded conductor of a multiconductor cable shall be permitted to be bare. 230.23 Size and Ampacity. (A) General. Conductors shall have sufficient ampacity to carry the current for the load as calculated in accordance with Parts II through V of Article 220 and s