neutral and grounded conductor
- Thread starter domnic
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chris kennedy
Senior Member
- Location
- Miami Fla.
- Occupation
- 60 yr old tool twisting electrician
Service or SDS?
I think 200.3 may be as close as you get to an answer to this.
I think 200.3 may be as close as you get to an answer to this.
- Occupation
- Licensed Electrician
250.20 maybe.
lauraj
Senior Member
- Location
- Portland, Oregon
You need to use a later edition of the code book where they actually have a definition for Neutral conductor in Article 100.
- Location
- Connecticut
- Occupation
- Engineer
NEC 2008 has a definition for Neutral Conductor in Article 100.
I think you are looking for 250.20, but 250.22 describes systems where the neutral would not be grounded so "a neutral is always a grounded conductor" wouldn't be correct.
Carultch
Senior Member
- Location
- Massachusetts
Neutral and grounded conductor are usually the same conductor, but both terms do have separate definitions.
A neutral is a conductor that is at the vector sum average of all the line/phase voltages in the system. In otherwords, plot the voltages of the system on a graph with the voltage-to-ground magnitude as the distance from the origin, and the phase angle around in a circle. The point that is equidistant from all phases in the system is the neutral.
A grounded conductor is a conductor that is at one point bonded to the equipment grounded conductor in some manner or another. Measure with a volt meter from it to the EGC, and you will get zero or near zero volts.
An example of a non-neutral grounded conductor, is the grounded conductor in corner grounded and high leg delta systems.
An example of a non-grounded neutral conductor, is the conductor that connects to the middle point of a floating wye system. Non-grounded neutral conductors are rare in the USA.
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- Location
- Connecticut
- Occupation
- Engineer
250.22 says "Circuits NOT to be grounded." So a neutral in an isolated power system in a hospital per 517.61 or 517.160 would not be grounded.
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Nuetral / Grounded Conductor
Nuetral / Grounded Conductor
I've always considered the grounded conductor of a MWBC a neutral, carrying the unbalanced current of the ungrounded phase conductors.
Conversely, the grounded conductor od a 2 wire circuit essential carries the same current as the phase conductor and thus is called a grounded conductor.
hope this helps.
Nuetral / Grounded Conductor
I've always considered the grounded conductor of a MWBC a neutral, carrying the unbalanced current of the ungrounded phase conductors.
Conversely, the grounded conductor od a 2 wire circuit essential carries the same current as the phase conductor and thus is called a grounded conductor.
hope this helps.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Neutral is the point that is equal potential to other points whether grounded or not.
If a system is to be grounded and has a neutral NEC requires the neutral to be the point that is grounded.
Until 2008(?) NEC the above was basically it, then NEC decided midpoint of one phase of a delta system that is intended to act like a neutral but isn't really a true neutral to the entire system is still to be called a neutral. (this is basically describing high leg delta systems here)
A two wire system or a three phase three wire system has no neutral, but you can ground any one conductor of either system and it becomes the grounded conductor.
What many seem to misunderstand is you could ground any point of any system, you just can't ground more then one point on the system or else fault current would flow. NEC covered applications just happen to require the neutral to be the grounded point if there is one. Even a DC source can ground either conductor you just can't ground both points.
If a system is to be grounded and has a neutral NEC requires the neutral to be the point that is grounded.
Until 2008(?) NEC the above was basically it, then NEC decided midpoint of one phase of a delta system that is intended to act like a neutral but isn't really a true neutral to the entire system is still to be called a neutral. (this is basically describing high leg delta systems here)
A two wire system or a three phase three wire system has no neutral, but you can ground any one conductor of either system and it becomes the grounded conductor.
What many seem to misunderstand is you could ground any point of any system, you just can't ground more then one point on the system or else fault current would flow. NEC covered applications just happen to require the neutral to be the grounded point if there is one. Even a DC source can ground either conductor you just can't ground both points.
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