- Aug 11, 2014
- Aug 11, 2014
The term neutral may not be strictly an exact quotation but it is a term that is has been customarily used by most of the world to indicate a grounded conductor quoted in N.A. by NEC/CEC/NFPA79.
e.g. in N.A. If a piece of equipment uses a 3ph 480v/600v transformer with a 120v secondary for control purposes, it is allowed to set up a local 'neutral' by earth grounding one of the secondary conductors, this then is termed neutral.
In other parts of the world a Neutral often refers to the star point of a 3phase transformer which is then earthed.
My electrical qualifications were actually obtained in the UK, where the term neutral has also been used as far as I can remember.
My beef in N.A. is the term ground is used for both chassis or frame ground And Earth ground.
Rather than as in U.K. Earth and Ground may be two distinct descriptions and the two symbols correctly used, rather than the way they are misused in N.A.
Not trying to nit pick here, but rather clarify the terms.
A neutral is not always a grounded conductor. Also, a grounded conductor may not be a neutral. An example where it's not a neutral, is single phase (2 wire)120v circuits.
The Nec has clarified this since the 2008 code cycle.
NFPA79 pertains to the wiring inside the machine controls, not the building wiring that we are talking about.
Obviously, whither or not this conductor is grounded makes a big difference in installation.
As far as US distinction of "ground", the actual terms are; equipment ground for chassis connection. And grounding electrode for earthing.
As far a symbols, I would not call one way incorrect. Rather a different way of identifying things.
Schematics vary greatly depending on what you are looking at and the country of origin.