andy@dixonelectrical.com
New member
- Location
- Huntington, WV, USA
per the 2005 NEC when can we use common neutrals for branch circuits
multiwire branch circuit common neutrals
- Thread starter andy@dixonelectrical.com
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david
Senior Member
- Location
- Pennsylvania
Multiwire branch circuits are legal, How they are identified and the disconnect rules for them have changed a lot through 2005, 2008, 2011. And I think 2014 restricts them further on emergency circuits, not that familiar with the 2014 code yet.
- Location
- Illinois
- Occupation
- retired electrician
We have to be careful here...what the code calls a "common neutral" is not really how most use that term in the field. A neutral for a multiwire branch circuit is not a "common neutral" as far as code rules. Under the code rules a "common neutral" is a neutral used with two or more ungrounded conductors where there is no potential between the ungrounded conductors.
In the 2005 code there are two specific provisions that say for those two cases a common neutral shall be permitted. The CMPs were trying to say that those two specific permissions acted to prohibit any other use of a "common neutral". It is my opinion that you can, under the 2005 code, use a "common neutral" anywhere you want to. This changed with the addition of 200.4 to the 2011 code.
In the 2005 code there are two specific provisions that say for those two cases a common neutral shall be permitted. The CMPs were trying to say that those two specific permissions acted to prohibit any other use of a "common neutral". It is my opinion that you can, under the 2005 code, use a "common neutral" anywhere you want to. This changed with the addition of 200.4 to the 2011 code.
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