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2011 Changes to the NEC – 250.102
The following is an instructional page from our 2011 Changes to the NEC Textbook/DVD Package complete with graphics and video where applicable. As part of our on-going effort to provide free resources to help the industry, we will be sending this content as part of a series of newsletters. Each newsletter will feature pages taken directly from our textbooks. This can be a great training resource for your organization!
There are some important features in this text which help to highlight the changes that you should be aware of:
- Each Code section which contains a change includes a summary of the change, followed by a paraphrase of the NEC text affected by the change. Any specific change is denoted by underlined text and in the corresponding chapter color
- Graphics with green borders and 2011 CC icons next to the heading are graphics that contain a 2011 change; graphics without a green border or icon are graphics that support the concept being discussed, but nothing in the graphic was affected by a 2011 Code change.
250.102 Bonding Conductors and Jumpers
This section has been revised extensively to incorporate the new term “supply-side bonding jumper.” Several revisions were also made to enhance usability of the NEC.
250.102 Bonding Conductors and Jumpers.
(A) Material. Equipment bonding jumpers must be copper.
(B) Termination. Equipment bonding jumpers must terminate by listed pressure connectors, terminal bars, exothermic welding, or other listed means [250.8(A)].
(C) Size Supply-Side Bonding Jumper.
(1) Single Raceway Installations. The supply-side bonding jumper is sized to Table 250.66, based on the largest ungrounded conductor within the raceway. If the ungrounded supply conductors are larger than 1,100 kcmil copper or 1,750 kcmil aluminum, the supply-side bonding jumper must be sized not less than 12½ percent of the area of the largest set of ungrounded supply conductors.
(2) Parallel Conductor Installations. If the ungrounded supply conductors are paralleled in two or more raceways or cables, the size of the supply-side bonding jumper for each raceway or cable is sized in accordance with Table 250.66, based on the size of the largest ungrounded conductors in each raceway or cable. A single supply-side bonding jumper for bonding two or more raceways or cables must be sized in accordance with (C)(1).
Question: What size equipment bonding jumper is required for a metal raceway containing 700 kcmil service conductors? Figure 250–76
(a) 1 AWG (b) 1/0 AWG (c) 2/0 AWG (d) 3/0 AWG
Answer: (c) 2/0 AWG [Table 250.66]
Figure 250-76
(3) Different Materials. If the ungrounded supply conductors and the supply-side bonding jumper are of different materials (copper or aluminum), the supply-side bonding jumper is sized on the assumed use of the same material.
(D) Load Side Equipment Bonding Jumper Sizing. Bonding jumpers on the load side of feeder and branch-circuit overcurrent devices are sized in accordance with 250.122, based on the rating of the circuit overcurrent device.
Author’s Comment: The equipment bonding jumper isn’t required to be larger than the largest ungrounded circuit conductors [250.122(A)].
Question: What size equipment bonding jumper is required for a metal raceway where the circuit conductors are protected by a 1,200A overcurrent device? Figure 250–77
(a) 1 AWG (b) 1/0 AWG (c) 2/0 AWG (d) 3/0 AWG
Answer: (d) 3/0 AWG [Table 250.122]
Figure 250-77
If a single equipment bonding jumper is used to bond two or more raceways, it must be sized according to 250.122, based on the rating of the largest circuit overcurrent device. Figure 250–78
Figure 250-78
(E) Installation. Equipment bonding jumpers, as well as bonding jumpers or conductors can be installed inside or outside of a raceway.
(1) Inside a Raceway or Enclosure. If installed inside a raceway, the conductors must be identified in accordance with 250.119 and if circuit conductors are spliced or terminated on equipment within a metal box, the equipment grounding conductor associated with those circuits must be connected to the box in accordance with 250.148.
(2) Outside a Raceway. If the equipment bonding jumper is installed outside of a raceway, its length must not exceed 6 ft and it must be routed with the raceway. Figure 250–79
Figure 250-79
(3) Protection. Aluminum bonding jumpers or conductors and equipment bonding jumpers must not be in contact with masonry, subject to corrosive conditions, or within 18 in. of the earth [250.64(A)] and conductors must be protected where subject to physical damage in accordance with 250.64(B).
ANALYSIS:With the new term “supply-side bonding jumper ” being introduced to the Code, this section has been revised to help distinguish the rules between a bonding jumper upstream from an overcurrent device and bonding jumpers downstream from an overcurrent device.
A change was also made to clarify that bonding jumpers on the load side of an overcurrent device must comply with all of Section 250.122, and not just Table 250.122.
Changes were also made to help clarify the rules in regard to bonding jumpers installed in a raceway as opposed to those installed outside of a raceway.
Finally, provisions for protection against corrosion for aluminum bonding jumpers have been added, and physical protection for all bonding jumpers have now been addressed.
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2011 NEC Changes DVD Package |
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Don't let the scale of the code changes intimidate you, this package will get you up to speed on the most essential 2011 NEC changes quickly. The book is well-organized, easy to follow, and the full-color illustrations bring the material to life. The DVDs bring together a group of experts from the field to discuss the changes and how they apply in the real-world.
This program includes the following items:
- Changes to the NEC 2011 Textbook
- Changes to the NEC 2011 DVD 1 & 2 includes Articles 90 - 810
Product Code: 11CCDVD
Price: $198.00
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