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2011 Changes to the NEC – 210.4
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.
2011 Changes to the NEC Part 1 |
210.4(B) Disconnecting Means
A new Informational Note was added to alert users of requirements in Article 240.
210.4 Multiwire Branch Circuits.
(B) Disconnecting Means. Each multiwire branch circuit must have a means to simultaneously disconnect all ungrounded conductors at the point where the branch circuit originates.
Figure 210-1 (Click on image to enlarge)
Note: Individual single-pole circuit breakers with handle ties identified for the purpose, or a breaker with a common internal trip, can be used for this application. See 240.15(B)(1).
Caution: This rule is intended to prevent people from working on energized circuits they thought were disconnected.
ANALYSIS: Section 210.4(B) requires that all multiwire branch circuits have a means to simultaneously disconnect the ungrounded conductors at the point of origination. While single-pole breakers with identified handle ties will typically satisfy this requirement, there are instances where a 2- or 3-pole breaker will be required. An example of this is where the branch circuit supplies both line-to-neutral and line-to-line loads [210.4(C) Ex 2 and 240.15(B)(1)]. The new Informational Note directs the NEC user to 240.15(B) in an effort to provide easier Code navigation. |
210.4(D) Grouping
The term “wire ties” was changed to “cable ties” in this subsection.
210.4 Multiwire Branch Circuits.
(D) Grouping. The ungrounded and neutral conductors of a multiwire branch circuit must be grouped together by cable ties or similar means at the point of origination.
Figure 210-2 (Click on image to enlarge)
Ex: Grouping isn’t required where the circuit conductors are contained in a single raceway or cable unique to that circuit that makes the grouping obvious.
Author’s Comment: Grouping all associated conductors of a multiwire branch circuit together by cable ties or other means within the point of origination makes it easier to visually identify the conductors of the multiwire branch circuit. The grouping will assist in making sure that the correct neutral is used at junction points and in connecting multiwire branch-circuit conductors to circuit breakers correctly, particularly where twin breakers are used. If proper diligence isn’t exercised when making these connections, two circuit conductors can be accidentally connected to the same phase.
Caution: If the ungrounded conductors of a multiwire circuit aren’t terminated to different phases or lines, the currents on the neutral conductor won’t cancel, but will add, which can cause an overload on the neutral conductor.
Figure 210-3 (Click on image to enlarge)
ANALYSIS: This change replaces the term “wire ties” with the more appropriate term “cable ties.” Cable ties are referred to in several locations in the Code, and the meaning of the term is widely understood by the industry. Wire ties, however, is a less specific term that may even include the ties that come with a loaf of bread!
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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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