Don't trust what you see

[roger]

Re: Don't trust what you see

Don,

I agree that the grounded conductor for the 3 phase 4 wire delta systems should be called a neutral.

it really doesn't matter if you,I, or anyone else think it should be called a neutral, the fact is in physical characteristics and properties it is a neutral.

However it is my opinion that under the accepted proposal for a definition of a neutral conductor, it will not meet the definition.

I think you are right in your opinion, but here lies the problem, if we are going to give it a definition it should be based on physics and not a feeble attempt at giving a name to a "thing" to fit conversational needs.

The definition requires that the system voltage be symmetrical and with a high leg, the system voltage is not symmetrical.

Two words in the quote above that are problems in defining a neutral is system and symmetrical.

Let's look at the single grounded winding as being a system in itself (it is) and the absolute center being the grounded point, "symmetrical system" could still be in the definition.

Maybe comments are needed on this proposal (1-122).

I think you are right there also.

Roger

 

[don_resqcapt19]

Re: Don't trust what you see

Roger,

it really doesn't matter if you,I, or anyone else think it should be called a neutral, the fact is in physical characteristics and properties it is a neutral.

For the purposes of the NEC, "neutral" is not defined. It needs to be, for the correct application of the code rules.
Don

 

[bennie]

Re: Don't trust what you see

Where is the definition of a neutral conductor creating any problems with the code interpretations?

Does anyone agree that on a B phase grounded delta 480 volt system, the B phase is a neutral?

Does anyone agree that on an open wye the B phase is also a neutral conductor?

Defining a neutral conductor is like defining a person, they are for different purposes at different times. There is no one size fits all.

 

[Ed MacLaren]

Re: Don't trust what you see

Where is the definition of a neutral conductor creating any problems with the code interpretations?

I've seen it here, on this forum.

I submit that effective communication is impossible if there isn't a precise, recognized meaning for technical terms, and agree that the term "neutral" must be defined.

Ed

 

[websparky]

Re: Don't trust what you see

Comments?

Neutral Grounding
Neutral grounding in electrical distribution systems helps prevent accidents to personnel and damage to property caused by: fire in case of lightning; a breakdown between primary and secondary windings of transformers; or accidental contact of high-voltage wires and low- voltage wires. If some point on the circuit is grounded (in this case neutral ground), lightning striking the wires will be conducted into the ground, and breakdown between the primary and secondary windings of a transformer will cause the primary transformer fuses to blow. Another advantage of neutral grounding is that it reduces the amount of insulation required for high-voltage transmission lines.

Neutral - a current-carrying conductor intended to deliver power to or from a
load normally at an electrical potential other than ground.

 

[bennie]

Re: Don't trust what you see

I stick to the; a neutral conductor is a conductor that is neutral. Websters defines the word neutral very well.

As I previously stated, the word neutral is an adjective when applied to electrical technology. An adjective is a descriptive word, in most cases it means neutral conductor in electrical theory.

I don't see any importance even if it is called the thang.

 

[roger]

Re: Don't trust what you see

Bennie, I think you have stumbled on the right definition.

If you and I were talking, and I said I installed two conductors, one on (A)phase and one on (B) phase sharing a THANG I think that would be all that was needed.

It certainly makes as much sense as the definition offered by some tech people.

Roger

[ September 02, 2003, 10:02 PM: Message edited by: roger ]

 

[bennie]

Re: Don't trust what you see

Roger: I love that word Clarification of the definition of a separately derived system is a lot more important than a neutral conductor, (that white thang).

The interpretation of a separately derived system is creating a completely different direction of technology.

I know you agree with me on this issue.

 

[pierre]

Re: Don't trust what you see

Originally posted by roger:

I think you are right in your opinion, but here lies the problem, if we are going to give it a definition it should be based on physics and not a feeble attempt at giving a name to a "thing" to fit conversational needs.


Roger this is the best statement made about the 'neutral' subject on all the forums.

A definition is necessary, maybe not for some like Bennie, because he has a thorough knowledge of the subject, but there are many who do not. Communication in this industry relies on the proper use of terms.

It is inevitable that the definition is forthcoming, maybe the people on this forum can come together with a consenus definition that we can send in as a group for the comment stage before the time is up.


Once the definition is in the NEC, it can (and will) have a large impact in the industry, especially the way it is worded now.

Here is my start

NEUTRAL CONDUCTOR
The circuit conductor of a three or four wire system (not including the equipment grounding conductor) that has an equal potential between it and the ungrounded conductors of the system.

Pierre

 

[mike@mikeholt.com]

Re: Don't trust what you see

From Mike Holt's "Basic Electrical Theory" textbook. He is the author of the graphics in question!

13.1 Neutral Conductor
According to the IEEE Dictionary, a neutral conductor is the conductor that has an equal potential difference between it and the other output conductors of a 3- or 4-wire system. Therefore, a neutral conductor would be the white/gray wire from a 3-wire 120/240V 1?, or a 4-wire 120/208V 3? system. Figure 13-2

Author?s Comment: Since a neutral conductor can only be from a 3- or 4-wire system, the white wire of a 2-wire 120V 1? or 4-wire 120/240V 3? high-leg delta system is not a neutral conductor ? it?s a grounded conductor. Figure 13-3

13.2 Grounded Conductor
The grounded conductor, according to Article 100 of the NEC, is a conductor that is intentionally grounded. In the case of home wiring (3-wire 120/240V 1?), the grounded conductor is also the neutral conductor, and it must be either white or gray in color in accordance with Section 200.6 of the National Electrical Code. Figure 13-3

 

[iwire]

Re: Don't trust what you see

Hi Mike and welcome to your electrical forum.

This Forum is a great teacher, I have learned a lot from the fine members of this forum.


Bob

 

[Guest]

Re: Don't trust what you see

I was wondering if the Big Bopper ever checked in here! Now I have my answer!

 

[roger]

Re: Don't trust what you see

Hello Mike, if we use a circuit sharing a grounded conductor between winding points X1 and X3 suplying more than one device on a single yoke, do we call this a Multi Wire Branch Circuit or do we have another exception to 210.4(C)?

Sorry, I have just seen this post.

Roger

[ September 20, 2003, 09:51 PM: Message edited by: roger ]

 

[tom baker]

Re: Don't trust what you see

Mike Holt states in his texts when a item is not defined, then the IEEE dictonary is used, for example the definiton of neutral.