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2011 Changes to the NEC – 250.94
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.
250.94 Bonding of Other Systems
The requirements for the intersystem bonding termination have been revised for clarity.
250.94 Intersystem Bonding Termination. An external accessible intersystem bonding termination for the connection of communications systems bonding conductors must be provided at service equipment or metering equipment enclosure and disconnecting means for buildings or structures supplied by a feeder,
Figure 250–72.
Figure 250-72 (Click on image to enlarge)
The intersystem bonding termination must:
(1) Be accessible for connection and inspection. Figure 250–73
Figure 250-73 (Click on image to enlarge)
(2) Consist of a set of terminals with the capacity for connection of not less than three intersystem bonding conductors.
(3) Not interfere with opening the enclosure for a service, building/structure disconnecting means, or metering equipment.
(4) Be securely mounted and electrically connected to service equipment, the meter enclosure, or exposed nonflexible metallic service raceway, or be mounted at one of these enclosures and be connected to the enclosure or grounding electrode conductor with a minimum 6 AWG copper conductor.
(5) Be securely mounted to the building/structure disconnecting means, or be mounted at the disconnecting means and be connected to the metallic enclosure or grounding electrode conductor with a minimum 6 AWG copper conductor. Figure 250–74
Figure 250-74 (Click on image to enlarge)
(6) The terminals must be listed as grounding and bonding equipment.
Author’s Comment: According to Article 100, an intersystem bonding termination is a device that provides a means to connect communications systems grounding and bonding conductors to the building grounding electrode system.
Ex: At existing buildings or structures, an external accessible means for bonding communications systems together can be by the use of a:
(1) Nonflexible metallic raceway,
(2) Grounding electrode conductor, or
(3) Connection approved by the authority having jurisdiction.
Note 2: Communications systems must be bonded to the intersystem bonding termination in accordance with the following Code requirements: Figure 250–75
• Antennas/Satellite Dishes, 810.15 and 810.21
• CATV, 820.100
• Telephone Circuits, 800.100
Figure 250-75 (Click on image to enlarge)
Author’s Comment: All external communications systems must be connected to the intersystem bonding terminal to minimize the damage to them from induced potential (voltage) differences between the systems from a lightning event.
ANALYSIS: The requirements for the bonding of communications and other limited energy systems were greatly revised in the 2008 NEC. While these changes make for a better system, the language that was used resulted in a lot of confusion and misapplication. Many changes were made to this section, including:
• Changing the term “bonding and grounding conductors” to “bonding and grounding electrode conductors.”
• Adding metering equipment enclosures as an allowable location for the intersystem bonding termination.
• Updating Code references in the exception.
• Adding optical fiber cables and network powered broadband systems into the Informational Note.
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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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