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Grounding versus Bonding

PART V. BONDING

Sections

250.102 Bonding Jumper.

(A) Bonding Material. Bonding jumpers must be of copper.

(B) Bonding Jumper Attachment. Bonding jumpers must terminate by exothermic welding, listed pressure connectors, listed clamps, or other listed means. Sheet-metal screws cannot be used for termination of bonding conductors or connection devices [250.8].

(C) Supply Side of Service—Bonding Jumper. Bonding jumpers for service raceways must be sized in accordance with Table 250.66, based on the ungrounded service conductors within the service raceway. Where service conductors are paralleled in two or more raceways or cables, the bonding jumper for each raceway or cable must be sized on the ungrounded service conductors in each raceway or cable.

Question: What size bonding jumper is required for a metal raceway containing 600 kcmil service conductors? Figure 250–144

(a) 1 AWG     (b) 1/0 AWG     (c) 2/0 AWG     (d) 3/0 AWG

Answer: (b) 1/0 AWG, Table 250.66
(D) Load Side of Service—Bonding Jumper. Bonding jumpers on the load side of service equipment must be sized in accordance with Table 250.122, based on the rating of the circuit-
protection device.

Question: What size bonding jumper is required for a metal raceway where the circuit conductors are protected by a 1,200A protection device? Figure 250–145

(a) 1 AWG     (b) 1/0 AWG     (c) 2/0 AWG     (d) 3/0 AWG

Answer: (d) 3/0 AWG, Table 250.122
A single bonding jumper sized in accordance with 250.122 can be used to bond multiple raceways or cables. Figure 250–146

(E) Installation. Where the equipment bonding jumper is installed outside a raceway, its length must not exceed 6 ft and it must be routed with the raceway. Figure 250–147

Exception: An equipment bonding jumper of any length can be used to bond isolated sections of metal raceways at outside pole locations. Figure 250–148


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