Main and Equipment Bonding Jumpers, NEC 250-79
(a) Material.
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A main bonding jumper or a bonding jumper required by
Section 250-26(a) shall be a wire, bus, screw, or similar suitable conductor. |
(b) Construction. Where a main bonding jumper is a screw only, the screw shall be identified with a green finish that shall be visible with the screw installed.
(c) Attachment. Main and equipment bonding jumpers shall be attached in the manner specified by the applicable provisions of Section 250-113 for circuits and equipment and by Section 250-115 for grounding electrodes.
(d) Size -- Equipment Bonding Jumper on Supply Side of Service and Main Bonding Jumper.
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The bonding jumper shall not be smaller than the sizes shown in
Table 250-94 for grounding electrode conductors. | |
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Where the service-entrance phase conductors are larger than 1100 kcmil copper or 1750 kcmil aluminum, the bonding jumper shall have an area not less than 12 1/2 percent of the area of the largest phase conductor except that, where the phase conductors and the bonding jumper are of different materials (copper or aluminum), the minimum size of the bonding jumper shall be based on the assumed use of phase conductors of the same material as the bonding jumper and with an ampacity equivalent to that of the installed phase conductors. | |
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Where the service-entrance conductors are paralleled in two or more raceways or cables, the equipment bonding jumper, where routed with the raceways or cables, shall be run in parallel. The size of the bonding jumper for each raceway or cable shall be based on the size of the service-entrance conductors in each raceway or cable. | |
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The bonding jumper for a grounding electrode conductor raceway or cable armor as covered in
Section 250-92(b) shall be the same size or larger than the required enclosed grounding electrode conductor. | |
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For direct-current systems, the size of the bonding jumper shall not be smaller than the system grounding conductor specified in
Section 250-93. |
(e) Size -- Equipment Bonding Jumper on Load Side of Service.
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The equipment bonding jumper on the load side of the service overcurrent devices shall not be smaller than the sizes listed in
Table
250-95. |
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A single common continuous equipment bonding jumper shall be permitted to bond two or more raceways or cables where the bonding jumper is sized in accordance with
Table
250-95 for the largest overcurrent device supplying circuits therein. |
(f) Installation -- Equipment Bonding Jumper.
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The equipment bonding jumper shall be permitted to be installed inside or outside of a raceway or enclosure. |
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Where installed on the outside, the length of the equipment bonding jumper shall not exceed 6 ft (1.83 m) and shall be routed with the raceway or enclosure. |
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Where installed inside of a raceway, the equipment bonding jumper shall comply with the requirements of Sections 250-114 and 310-12(b). |