Grouping of MWBC

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Dennis Alwon

Dennis Alwon

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I came across this in a text book and before I contact the author I want to throw it out here and see if you agree. I totally disagree. It seems like he is trying to say that multiwire branch circuit grounded conductors must be grouped but if the isn't a multiwire branch circuit then it doesn't need it as shown in "G". I think he is overlooking 200.4

200.4 Neutral Conductors. Neutral conductors shall be installed
in accordance with 200.4(A) and (B).
(A) Installation. Neutral conductors shall not be used for
more than one branch circuit, for more than one multiwire
branch circuit, or for more than one set of ungrounded feeder
conductors unless specifically permitted elsewhere in this Code.
(B) Multiple Circuits. Where more than one neutral conductor
associated with different circuits is in an enclosure, grounded
circuit conductors of each circuit shall be identified or
grouped to correspond with the ungrounded circuit conductor(
s) by wire markers, cable ties, or similar means in at least
one location within the enclosure.
Click to expand...


multiwire branch circuit Miller0002.jpg





Here is the explanation for fig G

multiwire branch circuit Miller0003.jpg
 
Must be an old book and I agree the statement is wrong. The neutral versus grounded conductor nonsense went away several code cycles ago in the 2008 NEC when the inserted the definition of the term Neutral Conductor. The letter G wording ignores that.
 
Maybe he's like me and living in the past :) You are, of course, correct but the requirement for multiple circuits was introduced in 2014. He hasn't caught up.
 
The author needs to review the definition of "neutral conductor" and "neutral point".
However I do recall it being taught, in the past, that a grounded conductor that is only associated with one ungrounded conductor is not a neutral.
 
I kinda agree with you, at the panel, it would make no difference, but at the next box down, the grounded conductor could be used on a different hot that it was paired with at the first box.
 
don_resqcapt19 said:
The author needs to review the definition of "neutral conductor" and "neutral point".
However I do recall it being taught, in the past, that a grounded conductor that is only associated with one ungrounded conductor is not a neutral.
Click to expand...
The author is well respected Charles Miller
 
don_resqcapt19 said:
The author needs to review the definition of "neutral conductor" and "neutral point".
However I do recall it being taught, in the past, that a grounded conductor that is only associated with one ungrounded conductor is not a neutral.
Click to expand...

Well technically that is true. A grounded conductor is only a neutral when there is ")" amps on the conductor.. At least that is my understanding but it is not in the code book AFAIK
 
don_resqcapt19 said:
I do recall it being taught, in the past, that a grounded conductor that is only associated with one ungrounded conductor is not a neutral.
Click to expand...
That was the thinking years ago but with the definition of neutral conductor it is no longer true.
 
I am sure as the years go by somethings get missed. I was pretty certain it was an error but I wanted to make sure
 
infinity said:
Could have been a reprint of an old copy into the new book.
Click to expand...
Exactly but I don't remember when it was that a multiwire branch circuit needed ties but single circuits did not. I remember when both didn't need ties or markings but not when one did and not the other
 
Dennis Alwon said:
Exactly but I don't remember when it was that a multiwire branch circuit needed ties but single circuits did not. I remember when both didn't need ties or markings but not when one did and not the other
Click to expand...
200.4(B) was new to the 2014 code and the language in the 2020 is the same as in the 2014.
 
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