I think I found my answer from an old posting by electric-ed:
(quote what electric-ed said)
The definition for neutral conductor that makes the most sense to me, and which happens to be the Canadian Electrical Code definition -
"Neutral means that conductor(when one exists) of a polyphase circuit, or a single phase, 3-wire circuit, which is intended to have a voltage such that the voltage differences between it and each of the other conductors are approximately equal in magnitude and equally spaced in phase."
According to this definition-
1. The grounded conductor of any wye connected system, or center tapped single-phase system, is a neutral.
2. The grounded conductor of a 2-wire, single phase system is not a neutral. (I just think of it as a "return".
3. The grounded conductor of a 4-wire delta is only a neutral for phases A and C, but not for the high leg.
4. The grounded conductor of a corner grounded 3-wire delta system is not a neutral.
Thanks
