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#85661 - 07/27/03 04:41 AM New Definition of Neutral Accepted in the 2005 NEC
Joe Tedesco Offline
Member

Registered: 10/07/00
Posts: 3325
Loc: Boston, Massachusetts USA
 Quote:
1-122 Log #2457 NEC-P01
(100–Neutral Conductor (New) )
Final Action: Accept in Principle

TCC Action:

It was the action of the Technical Correlating Committee that this Proposal be referred to Code-Making Panels 2, 4, 5, and 13 for comment.

Submitter: Paul Dobrowsky Holley, NY

Recommendation:

Add a new definition as follows:

Neutral Conductor. A conductor that is connected to the neutral point of a system and is intended for carrying current during normal conditions.

Substantiation:

The terms "grounded conductor" and "neutral" are frequently interchanged and misused.

The term "neutral" is used extensively in product standards, product literature and other documents (identified, as white or gray) - even where only two current carrying conductors are present.

This definition would allow that a conductor to be called a neutral even when a two-wire extension is connected to a system that has a neutral.

IEC 60204-1 contains the following definition: neutral conductor (symbol N) conductor connected to the neutral point of a system and capable of contributing to the transmission of electrical energy [IEV 826-01-03]

Panel Meeting Action: Accept in Principle

Revise proposed text as follows:

Neutral Conductor. A conductor, other than a grounding conductor, that is connected to the common point of a wye connection in a polyphase system or the point of a symmetrical system which is normally at zero voltage.

Panel Statement:

This defined term is based on the definition of neutral conductor in IEEE Std. 100-1992 and the term "neutral point" from IEEE Std. 100-1992. The panel believes this action meets the intent of the submitter. Refer to CMPs 2, 4, 5, and 13 for comment.

Number Eligible to Vote: 12
Affirmative: 9 Negative: 3 Ballot Results:
Explanation of Negative:

BARRIOS: The proposed definition as modified by the panel is too complex and is not needed.

The common "wye" point as referenced in the definition only applies to three-phase systems, not all polyphase systems, and it is not clear what "zero voltage" is referenced to in "symmetrical systems".

MCMAHILL: The definition Panel 1 proposed will only cause confusion in the use of the term "neutral." The submitter of the proposal has a valid concern in that the terms "grounded conductor" and "neutral" are frequently interchanged and misused.

This is a standard practice in the electrical industry. Instead of adding a new definition, it is reasonable to simply add the word "neutral" to the definition of "grounded conductor" (i.e., Grounded (neutral) conductor). This will keep things simple. After all, it is fair to say that not all grounded conductors are neutrals, but it is also fair to say that all neutrals are grounded conductors.

MINICK:Because of the word "or", the suggested definition does not appear to take into account that a wye system is also a symmetrical system. The use of the term "symmetrical system" appears to include a single-phase system but not the symmetrical phase of a three-phase delta as a "delta system" is not a symmetrical system.

In addition, any definition accepted by CMP 1 should aid the reader in the application and in understanding of the requirements of the NEC. The accepted definition does neither.

The term neutral appears to be well understood by the users of the NEC in that conductors may be neutral at a given point in time and then simply current supply or return conductors at other times within the same installed electrical scheme without alteration of the installation in any way.

In this way, a "neutral" is somewhat of a moving target that is recognized when present. No real substantiation was submitted citing specific instances where any alluded misuse occurred.
_________________________
Joe Tedesco, NEC Consultant

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2014 / 2011 NEC & Related Books and Study Guides
#85662 - 07/27/03 08:56 AM Re: New Definition of Neutral Accepted in the 2005 NEC
ThinkGood Offline
Member

Registered: 08/07/02
Posts: 1084
Loc: Milwaukee, WI
 Quote:
...normally at zero voltage...


Is it not normal for a neutral to carry voltage? This is quite common, according to what I have read, when a load is not balanced.

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#85663 - 07/27/03 04:00 PM Re: New Definition of Neutral Accepted in the 2005 NEC
Redsy Offline
Member

Registered: 03/28/01
Posts: 2138
Loc: Bucks County PA
Thinkgood,
You may be confusing voltage with current.
The neutral, as defined, will be at zero voltage with respect to ground.
Under balanced conditions, the current will be zero, and will increase with an increase in imbalance.
BTW,
I like your wedding photo.
Mazel Tov! (I think?)

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#85664 - 07/27/03 04:56 PM Re: New Definition of Neutral Accepted in the 2005 NEC
ThinkGood Offline
Member

Registered: 08/07/02
Posts: 1084
Loc: Milwaukee, WI
Redsy:

I just re-read the definition.

 Quote:
...the point of a symmetrical system which is normally at zero voltage.


It's quite clear. I "jumped the gun" and took it to mean that the neutral is normally at zero voltage. That's not what was printed.

P. S. Thanks. Yes, Mazal Tov is correct.

[This message has been edited by ThinkGood (edited 07-27-2003).]

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#85665 - 07/27/03 05:38 PM Re: New Definition of Neutral Accepted in the 2005 NEC
sparky Offline
Member

Registered: 10/18/00
Posts: 5545
proof 3/4 of the panel hasn't the brains God gave geese........

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#85666 - 07/27/03 08:57 PM Re: New Definition of Neutral Accepted in the 2005 NEC
ga.sparky56 Offline
Member

Registered: 11/24/02
Posts: 582
Loc: young harris georgia usa
Imho this micro-legislated definition won't change a thing for the guy in the trenches.

The more I understand about the code-making process,the more it smells like politicians and lobbyists.

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#85667 - 07/28/03 04:36 AM Re: New Definition of Neutral Accepted in the 2005 NEC
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
Just to show that you're not always alone over confusing definitions, you might find this older definition of a neutral from the British IEE of interest:
 Quote:

Neutral conductor. The neutral conductor of a 3-phase 4-wire system, the conductor of a single-phase or d.c. installation which is earthed by the supply undertaking (or otherwise at the source of the supply), or the middle wire or common return conductor of a 3-wire d.c. or 3-wire single-phase a.c. system.

It's clear that they allow the term neutral to be applied to the grounded conductor of a 2-wire system, but notice how when it comes to 3-ph wye systems they created a nice circular reference!

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#85668 - 08/09/03 12:35 PM Re: New Definition of Neutral Accepted in the 2005 NEC
engy Offline
Member

Registered: 06/25/02
Posts: 15
Loc: Minnesota
Why not keep it more simple and use "grounded conductor" in the definition?


Neutral Conductor: A grounded conductor that is connected to the common point of polyphase system, or the mid-point of a single-phase system.

Even more simple...

Neutral Conductor: A grounded conductor that is connected to the neutral point of a system.

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#85669 - 08/09/03 08:01 PM Re: New Definition of Neutral Accepted in the 2005 NEC
Joe Tedesco Offline
Member

Registered: 10/07/00
Posts: 3325
Loc: Boston, Massachusetts USA
These are good suggestions and you can send in a comment, here's the form:
http://joetedesco.com/nec/NEC05Comment.pdf
_________________________
Joe Tedesco, NEC Consultant

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