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conductor or a bonding jumper in accordance with 250.102(E)(2) shall be installed. o f. If liquidtight 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. * (7) Flexible metallic tu...

conductor or a bonding jumper in accordance with 250.102(E)(2) shall be installed. o f. If liquidtight 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. * (7) Flexible metallic tubing if the tubing is terminated in listed fittings and meeting the following conditions: o a. The circuit conductors contained in the tubing are protected by overcurrent devices rated at 20 amperes or less. o b. The combined length of flexible metal conduit, flexible metallic tubing, and liquidtight flexible metal conduit in the same effective ground-fault current path does not exceed 1.8 m (6 ft). * (8) Armor of Type AC cable as provided in 320.108. * (9) The copper sheath of mineral-insulated, metal-sheathed cable Type MI. * (10) Type MC cable that provides an effective ground-fault current path in accordance with one or more of the following: o a. It contains an insulated or uninsulated equipment grounding conductor in compliance with 250.118(1). o b. The combined metallic sheath and uninsulated equipment grounding/bonding conductor of interlocked metal tape-type MC cable that is listed and identified as an equipment grounding conductor o c. The metallic sheath or the combined metallic sheath and equipment grounding conductors of the smooth or corrugated tube-type MC cable that is listed and identified as an equipment grounding conductor * (11) Cable trays as permitted in 392.10 and 392.60. * (12) Cablebus framework as permitted in 370.60(1). * (13) Other listed electrically continuous metal raceways and listed auxiliary gutters. * (14) Surface metal raceways listed for grounding. Informational Note: See Article 100 for a definition of effective ground-fault current path. (B) Not Permitted. The following shall not be used as equipment grounding conductors. * (1) Grounding electrode conductors Exception: A wire-type equipment grounding conductor installed in compliance with 250.6(A) and the applicable requirements for both the equipment grounding conductor and the grounding electrode conductor in Parts II, III, and VI of this article shall be permitted to serve as both an equipment grounding conductor and a grounding electrode conductor. * (2) Structural metal frame of a building or structure ENHANCED CONTENT Collapse Equipment grounding conductors (EGCs) and grounding electrode conductors (GECs) have specific functions. GECs are required to be a wire- or busbar-type conductor in accordance with 250.62, whereas EGCs are permitted to be any of the types listed in 250.118. This exception permits a wire-type conductor to be used for both purposes if it satisfies all applicable requirements for both the EGC and the GEC and it does not carry current during normal operating conditions. 250.119 Identification of Wire-Type Equipment Grounding Conductors. (A) General. Unless required elsewhere in this Code, equipment grounding conductors shall be permitted to be bare, covered, or insulated. Individually covered or insulated equipment grounding conductors of the wire type shall have a continuous outer finish that is either green or green with one or more yellow stripes except as permitted in this section. Conductors with insulation or individual covering that is green, green with one or more yellow stripes, or otherwise identified as permitted by this section shall not be used for ungrounded or grounded circuit conductors. Exception No. 1: Power-limited Class 2 or Class 3 cables, power-limited fire alarm cables, or communications cables containing only circuits operating at less than 50 volts ac or 60 volts dc if connected to equipment not required to be grounded shall be permitted to use a conductor with green insulation or green with one or more yellow stripes for other than equipment grounding purposes. Exception No. 2: Flexible cords having an integral insulation and jacket without an equipment grounding conductor shall be permitted to have a continuous outer finish that is green. Informational Note: An example of a flexible cord with integral-type insulation is Type SPT-2, 2 conductor. Exception No. 3: Conductors with green insulation shall be permitted to be used as ungrounded signal conductors where installed between the output terminations of traffic signal control and traffic signal indicating heads. Signaling circuits installed in accordance with this exception shall include an equipment grounding conductor in accordance with 250.118. Wire-type equipment grounding conductors shall be bare or have insulation or covering that is green with one or more yellow stripes. ENHANCED CONTENT Collapse In general, most limited-energy ac systems are not required to be grounded per 250.20(A). Similarly, 250.162 does not require grounding of dc systems operating at 60 volts or less. Per 250.112(I), if the ac or dc limited-energy system is not required to be grounded, the equipment associated with circuits supplied from such systems is not required to be connected to an equipment grounding conductor. (B) Conductors 4 AWG and Larger. Equipment grounding conductors 4 AWG and larger shall comply with the following: * (1) At the time of installation, if the insulation does not comply with 250.119(A), it shall be permanently identified as an equipment grounding conductor at each end and at every point where the conductor is accessible. Exception: Conductors 4 AWG and larger shall not be required to be marked in conduit bodies that contain no splices or unused hubs. * (2) Identification shall encircle the conductor and shall be accomplished by one of the following: o a. Stripping the insulation or covering from the entire exposed length o b. Coloring the insulation or covering green at the termination o c. Marking the insulation or covering with green tape or green adhesive labels at the termination (C) Multiconductor Cable. One or more insulated conductors in a multiconductor cable, at the time of installation, shall be permitted to be permanently identified as equipment grounding conductors at each end and at every point where the conductors are accessible by one of the following means: * (1) Stripping the insulation from the entire exposed length. * (2) Coloring the exposed insulation green. * (3) Marking the exposed insulation with green tape or green adhesive labels. Identification shall encircle the conductor. (D) Flexible Cord. Equipment grounding conductors in flexible cords shall be insulated and shall have a continuous outer finish that is either green or green with one or more yellow stripes. 250.120 Equipment Grounding Conductor Installation. An equipment grounding conductor shall be installed in accordance with 250.120(A), (B), and (C). (A) Raceway, Cable Trays, Cable Armor, Cablebus, or Cable Sheaths. If it consists of a raceway, cable tray, cable armor, cablebus framework, or cable sheath or if it is a wire within a raceway or cable, it shall be installed in accordance with the applicable provisions in this Code using fittings for joints and terminations approved for use with the type of raceway or cable used. All connections, joints, and fittings shall be made tight using suitable tools. Informational Note: See the UL Guide Information for Electrical Circuit Integrity Systems (FHIT) for equipment grounding conductors installed in a raceway that are part of a listed electrical circuit protective system or a listed fire-resistive cable system. (B) Aluminum and Copper-Clad Aluminum Conductors. Equipment grounding conductors of bare, covered, or insulated aluminum or copper-clad aluminum shall comply with the following: * (1) Unless part of an applicable cable wiring method, bare or covered conductors shall not be installed if subject to corrosive conditions or be installed in direct contact with concrete, masonry, or the earth. * (2) Terminations made within outdoor enclosures that are listed and identified for the environment shall be permitted within 450 mm (18 in.) of the bottom of the enclosure. * (3) Aluminum or copper-clad aluminum conductors external to buildings or enclosures shall not be terminated within 450 mm (18 in.) of the earth, unless terminated within a listed wire connector system. (C) Equipment Grounding Conductors Smaller Than 6 AWG. If not routed with circuit conductors as permitted in 250.130(C) and 250.134, Exception No. 2, equipment grounding conductors smaller than 6 AWG shall be protected from physical damage by an identified raceway or cable armor unless installed within hollow spaces of the framing members of buildings or structures and if not subject to physical damage. 250.122 Size of Equipment Grounding Conductors. (A) General. Copper, aluminum, or copper-clad aluminum equipment grounding conductors of the wire type shall not be smaller than shown in Table 250.122. The equipment grounding conductor shall not be required to be larger than the circuit conductors supplying the equipment. If a cable tray, a raceway, or a cable armor or sheath is used as the equipment grounding conductor, as provided in 250.118 and 250.134(1), it shall comply with 250.4(A)(5) or (B)(4). Equipment grounding conductors shall be permitted to be sectioned within a multiconductor cable, provided the combined circular mil area complies with.Table 250.122. (B) Increased in Size. If ungrounded conductors are increased in size for any reason other than as required in 310.15(B) or 310.15(C), wire-type equipment grounding conductors, if installed, shall be increased in size proportionately to the increase in circular mil area of the ungrounded conductors. Exception: Equipment grounding conductors shall be permitted to be sized by a qualified person to provide an effective ground fault current path in accordance with 250.4(A)(5) or (B)(4) ENHANCED CONTENT Collapse Generally, the minimum-sized EGC is selected from Table 250.122 based on the rating or setting of the feeder or branch-circuit OCPD(s). Where the ungrounded circuit conductors are increased in size, the EGCs must be increased proportionately. This will lower the overall impedance of the ground- fault current return path, which will facilitate operation of the OCPD in the event of a line-to-ground fault. Multiple Circuits. A single equipment grounding conductor shall be permitted to be installed for multiple circuits that are installed in the same raceway, cable, trench, or cable tray. It shall be sized from Table 250.122 for the largest overcurrent device protecting circuit conductors in the raceway, cable, trench, or cable tray. Equipment grounding conductors instal?led in cable trays shall meet the minimum requirements of 392.10(B)(1)(c). ENHANCED CONTENT Collapse A single EGC serving multiple circuits is required to be sized based on the size of the largest circuit OCPD supplied; it is not likely that all circuits will develop faults at the same time. For example, three 3-phase circuits in the same raceway, protected by overcurrent devices rated 30, 60, and 100 amperes, would require only one EGC, sized according to the largest overcurrent device (in this case, 100 amperes). Therefore, according to Table 250.122, an 8 AWG copper or 6 AWG aluminum conductor or copper-clad aluminum conductor is required. Motor Circuits. Equipment grounding conductors for motor circuits shall be sized in accordance with 250.122(D)(1) or (D)(2). General. The equipment grounding conductor size shall not be smaller than determined by 250.122(A) based on the rating of the branch-circuit short-circuit and ground-fault protective device. Instantaneous-Trip Circuit Breaker and Motor Short-Circuit Protector. If the overcurrent device is an instantaneous-trip circuit breaker or a motor short-circuit protector, the equipment grounding conductor shall be sized not smaller than that given by 250.122(A) using the maximum permitted rating of a dual element time-delay fuse selected for branch-circuit short-circuit and ground-fault protection in accordance with 430.52(C)(1)(a). Flexible Cord and Fixture Wire. The equipment grounding conductor in a flexible cord with the largest circuit conductor 10 AWG or smaller, and the equipment grounding conductor used with fixture wires of any size in accordance with 240.5, shall not be smaller than 18 AWG copper and shall not be smaller than the circuit conductors. The equipment grounding conductor in a flexible cord with a circuit conductor larger than 10 AWG shall be sized in accordance with Table 250.122. Conductors in Parallel. For circuits of parallel conductors as permitted in 310.10(G), the equipment grounding conductor shall be installed in accordance with 250.122(F)(1) or (F)?(2). Conductor Installations in Raceways, Auxiliary Gutters, or Cable Trays. Single Raceway or Cable Tray, Auxiliary Gutter, or Cable Tray. If circuit conductors are connected in parallel in the same raceway, auxiliary gutter, or cable tray, a single wire-type conductor shall be permitted as the equipment grounding conductor. The wire-type equipment grounding conductor shall be sized in accordance with 250.122 based on the overcurrent protective device for the feeder or branch circuit. Multiple Raceways. If conductors are installed in multiple raceways and are connected in parallel, a wire-type equipment grounding conductor, if used, shall be installed in each raceway and shall be connected in parallel. The equipment grounding conductor installed in each raceway shall be sized in accordance with 250.122 based on the rating of the overcurrent protective device for the feeder or branch circuit. Wire-Type Equipment Grounding Conductors in Cable Trays. Wire-type equipment grounding conductors installed in cable trays shall meet the minimum requirements of 392.10(B)(1)(c). Metal Raceways, Auxiliary Gutters, or Cable Trays. Metal raceways or auxiliary gutters in accordance with 250.118 or cable trays complying with 392.60(B) shall be permitted as the equipment grounding conductor. Multiconductor Cables. Except as provided in 250.122(F)(2)(c) for raceway or cable tray installations, the equipment grounding conductor in each multiconductor cable shall be sized in accordance with 250.122 based on the overcurrent protective device for the feeder or branch circuit. If circuit conductors of multiconductor cables are connected in parallel, the equipment grounding conductor(s) in each cable shall be connected in parallel. If multiconductor cables are paralleled in the same raceway, auxiliary gutter, or cable tray, a single equipment grounding conductor that is sized in accordance with 250.122 shall be permitted in combination with the equipment grounding conductors provided within the multiconductor cables and shall all be connected together. Equipment grounding conductors installed in cable trays shall meet the minimum requirements of 392.10(B)(1)?(c). Cable trays complying with 392.60(B), metal raceways in accordance with 250.118, or auxiliary gutters shall be permitted as the equipment grounding conductor. ENHANCED CONTENT Collapse A full-sized EGC is required to prevent overloading and possible burnout of the conductor should a ground fault occur along one of the parallel branches. The installation conditions for paralleled conductors prescribed in 310.10(G) result in proportional distribution of the current-time duty among the several paralleled grounding conductors only for overcurrent conditions downstream of the paralleled set of circuit conductors. The exhibit below shows a parallel arrangement with two nonmetallic conduits installed underground. A ground fault at the enclosure will cause the EGC in the top conduit to carry more than its proportionate share of fault current. The fault is fed by two different conductors of the same phase, one from the left and one from the right. The shortest and lowest-impedance path to ground from the fault to the supply panelboard is through the EGC in the top conduit. The grounding path from the fault through the bottom conduit is longer and of higher impedance. Therefore, the EGC in each raceway must be capable of carrying a major portion of the fault current without burning open. Generally, if cables are used in parallel, the EGC in each cable is required to be sized in accordance with 250.122 based on the rating or setting of the OCPD that is protecting the conductors connected in parallel. The EGC might have to be larger than the ungrounded conductor in an individual cable that is used as part of a larger parallel set. The cross-sectional areas of sectioned EGCs in an individual cable are permitted by 250.122(A) to be added together to meet the requirement of a fully sized EGC in each cable. For multiconductor cables installed in a raceway, cable tray, or auxiliary gutter, a separate bare, covered, or insulated full-sized EGC that is based on the rating of the OCPD protecting the parallel cable circuit can be installed as an alternative to requiring that each cable contain a full-sized EGC. However, this separate, full-sized EGC and any EGCs contained in the multiconductor cables are required to be connected together at each end of the circuit. (G) Feeder Taps. Equipment grounding conductors installed with feeder taps shall not be smaller than shown in Table 250.122 based on the rating of the overcurrent device ahead of the feeder on the supply side ahead of the tap but shall not be required to be larger than the tap conductors. Table 250.122 Minimum Size Equipment Grounding Conductors for Grounding Raceway and Equipment Rating or Setting of Automatic Overcurrent Device in Circuit Ahead of Equipment, Conduit, etc., Not Exceeding (Amperes) Size (AWG or kcmil) Copper Aluminum or Copper-Clad Aluminum 15 14 12 20 12 10 60 10 8 100 8 6 200 6 4 300 4 2 400 3 1 500 2 1/0 600 1 2/0 800 1/0 3/0 1000 2/0 4/0 1200 3/0 250 1600 4/0 350 2000 250 400 2500 350 600 3000 400 600 4000 500 750 5000 700 1250 6000 800 1250 Note: Where necessary to comply with 250.4(A)(5) or (B)(4), the equipment grounding conductor shall be sized larger than given in this table. See installation restrictions in 250.120. 250.124 Equipment Grounding Conductor Continuity. (A) Separable Connections. Separable connections such as those provided in drawout equipment or attachment plugs and mating connectors and receptacles shall provide for first-make, last-break of the equipment grounding conductor. First-make, last- break shall not be required if interlocked equipment, plugs, receptacles, and connectors preclude energization without grounding continuity. (B) Switches. No automatic cutout or switch shall be placed in the equipment grounding conductor of a premises wiring system unless the opening of the cutout or switch disconnects all sources of energy. 250.126 Identification of Wiring Device Terminals. The terminal for the connection of the equipment grounding conductor shall be identified by one of the following: * (1) A green, not readily removable terminal screw with a hexagonal head. * (2) A green, hexagonal, not readily removable terminal nut. * (3) A green pressure wire connector. If the terminal for the equipment grounding conductor is not visible, the conductor entrance hole shall be marked with the word green or ground, the letters G or GR, a grounding symbol, or otherwise identified by a distinctive green color. If the terminal for the equipment grounding conductor is readily removable, the area adjacent to the terminal shall be similarly marked. Informational Note: See Informational Note Figure 250.126. Informational Note Figure 250.126 One Example of a Symbol Used to Identify the Grounding Termination Point for an Equipment Grounding Conductor. Part VII. Methods of Equipment Grounding Conductor Connections 250.130 Equipment Grounding Conductor Connections. Equipment grounding conductor connections at the source of separately derived systems shall be made in accordance with 250.30(A)(1). Equipment grounding conductor connections at service equipment shall be made as indicated in 250.130(A) or (B). For replacement of non-grounding-type receptacles with grounding-type receptacles, or snap switches without an equipment grounding terminal with snap switches with an equipment grounding terminal, and for branch-circuit extensions only in existing installations that do not have an equipment grounding conductor in the branch circuit, connections shall be permitted as indicated in 250.130(C). (A) For Grounded Systems. The connection shall be made by bonding the equipment grounding conductor to the grounded service conductor and the grounding electrode conductor. ENHANCED CONTENT Collapse The grounding and bonding arrangement required by 250.130(A) for a grounded system is illustrated below, showing the connection of the EGC (bus) to the enclosures and to the grounded service conductor. For Ungrounded Systems. The connection shall be made by bonding the equipment grounding conductor to the grounding electrode conductor. Replacement of Nongrounding Receptacle or Snap Switch and Branch Circuit Extensions. The equipment grounding conductor that 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: Any accessible point on the grounding electrode system as described in 250.50 Any accessible point on the grounding electrode conductor The equipment grounding terminal bar within the enclosure where the branch circuit for the receptacle or branch circuit originates An equipment grounding conductor that is part of another branch circuit that originates from the enclosure where the branch circuit for the receptacle, snap switch, or branch circuit originates For grounded systems, the grounded service conductor within the service equipment enclosure 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. ENHANCED CONTENT Collapse Section 250.130(C) applies to both ungrounded and grounded systems, but its most common application is for receptacle replacement or branch-circuit extensions in single-phase, 120- volt, 15- and 20-ampere branch circuits. A non-grounding-type receptacle can be replaced with a grounding type receptacle under the conditions of this section. This section does not permit a separate EGC to be connected to the metal water piping of a building beyond the first 5 feet because it is not considered a GEC [unless the conditions of 250.68(C)(1) Exception apply] or part of the electrode system. The exhibit below shows a branch-circuit extension made from an existing receptacle outlet without an EGC to a new receptacle outlet. A branch-circuit extension made from an existing receptacle outlet without an EGC to a new receptacle outlet is shown below. The new receptacle is required to be a grounding-type device. The EGC in the new Type NM cable used to extend the branch circuit is connected to the separate EGC installed per 250.130(C) at the new metal box enclosing the new receptacle. Based on 250.148(C), the EGC is required to be connected to the new metal box installed to enclose the new receptacle and to the existing metal box where the branch-circuit extension originates. The existing non- grounding-type receptacle can remain. If the installer chooses, a new grounding-type receptacle can be installed as a replacement for the non- grounding- type device. 250.132 Short Sections of Raceway or Cable Armor. Isolated sections of metal raceway or cable armor, if required to be connected to an equipment grounding conductor, shall be connected in accordance with 250.134. 250.134 Equipment Fastened in Place or Connected by Permanent Wiring Methods (Fixed). Unless connected to the grounded circuit conductor as permitted by 250.32, 250.140, and 250.142, non-current-carrying metal parts of equipment, raceways, and othe