This article was posted 05/26/2006 and is most likely outdated.

Grounding vs Bonding Online Training
 

 
Grounding vs Bonding: 250.102 Bonding Jumper

May 26, 2006  

  View Comments | Add Comments | Notify Me When Comments Are Added  

PART V. BONDING   Hi Res - Cable/DSL [728Kb]
VIEWING Video FILE requires
Real Media Player [ FREE ]
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


imageSend to a Friend


Figure 250–144
(Click on image to enlarge)


Figure 250–145
(Click on image to enlarge)


Figure 250–146
(Click on image to enlarge)


Figure 250–147
(Click on image to enlarge)


Figure 250–148
(Click on image to enlarge)

Copyright © 2006 Mike Holt Enterprises,Inc.
1-888-NEC-CODE (1-888-632-2633)

 

Comments

  • In reviewing Figure 240.144, it appears that "supply side of service bonding jumper" and "grounded conductor" have been combined.

    Let us review how the NEC uses the terms "bonding" and "grounded conductor".

    Atrticle 100 definitions "Bonding Jumper. A reliable conductor to ensure the required electrical conductivity between metal parts required to be electrically connected."

    "Grounded Conductor. A system or circuit conductor that is intentionally grounded."

    "Grounding Electrode Conductor. The conductor used to connect the grounding electrode(s) to the equipment grounding conductor, to the grounded conductor, or to both, at the service, at each building or structure where supplied by a feeder(s) or branch circuit(s) or at the source of a separately derived system.

    Article 250.24(C) Grounded Conductor Brought to Service Equipment "Where an AC system operating at less that 1000 volts is grounded at any point, the grounded conductor(s) shall be run to each service disconnecting means enclosure. The grounded conductor shall be installed in accordance with 250.24(C) (1) through (C)(3)"

    Article 250.24(C)(1) Routing and sizing "This conductor shall be routed with the phase conductors and shall not be smaller than the required rounding electrode conductor specified in Table 250.66...In addition, for service-entrance phase conductors larger than 1100kcmil copper or 1750kcmil aluminum, the grounded conductor shall not be smaller than 12 1/2 percent of the area of the largest service-entrance conductor."

    Revisit the first sentence of 250.102(C) "Bonding jumpers for service raceways..." This is requiring service entrance raceways to be bonded to the service entrance enclosure.

    The Figure indicates a grouded conductor being routed with the service entrance conductors. The bonding jumper for this Figure should have been drawn as in Figure 250.45 where the bonding jumper is connected to the raceways and to the enclosure. The conductor in Figure 250.144 identified as the service side grounding bonding jumper should be identified as the grounded conductor.

    Shorty

    • Reply from: Mike Holt   
    Shorty, you got us! I see that we forgot to add the grounded neural conductor (assuming that this was a grounded system). I agree that we should show the service bonding jumper from the raceway to the equipment grounding (bonding) terminal.
Reply to this comment
* Your Name:
   Your name will appear under your comments.

* Your Email:
   Your email address is not displayed.
* Comments:

This newsletter is closed to new comments.

Email Notification Options:
Notify me when a reply is posted to this comment
Notify me whenever a comment is posted to this newsletter