Meaning of "Phase"

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Re: Meaning of "Phase"

Rattus,
True, but the neutral is designed to carry continuous current while the EGC (we hope) never carries current.
Click to expand...
where does an EGC (grounding) conductor enter into the conversation? ;)

The only time the grounded conductor is a "Neutral" (in the pure sense)is when the combined voltage drop across the loads and conductors on both legs are equal at the center of the circuit. Now what we have is a series circuit at the winding end to end voltage where the grounded conductor (Neutral) is playing no role in the circuit.

Roger
 
Re: Meaning of "Phase"

Yes there are such things as ungrounded neutrals, but they are rare (NEC 250.22).

Quote from Square D Digest 173 page 13-5 concerning hospital isolation panels, "Similar to a standard distribution panel or load center, it can supply either 208/120 or 240/120 volts of ungrounded, isolated, single phase power..."
 
Re: Meaning of "Phase"

The NEC has had a difficult time over the years defining "neutral" or "neutral conductor." There have been many definition Proposals over the years but none have made into Art 100.

In the 2005 cycle there were three Proposals and one was accepted "in principle." Its even in the Draft. It was put on "hold" after 11 public Comments were made - not all necessarily in opposition.

The primary problem is that there are at least 5 CMPs with a vested interest in the definition and they are not 100% compatible with a single, simple definition and any truly comprehensive definition becomes unruly - at least in the minds of the CMPs.
 
Re: Meaning of "Phase"

Roger, I was complaining about the names being so similar for conductors with different functions. Namely, the grounded and grounding conductors.
 
Re: Meaning of "Phase"

A while ago I tentatively decided I like these terms:

Grounded Supply Conductor
Supply conductor
Bonding Conductor
Service Grounding Conductor
 
Re: Meaning of "Phase"

Rattus, this is my current perspective.

I was really big on the idea of using the term neutral. I think I changed mind about it when I considered a system that has both neutral grounded and corner grounded transformers. (It occurred to me after arguing with Iwire). What really matters (at least in my mind) is a zero reference.

When I used to build and work with DC power supplies (a bipolar supply has a voltage on either side of zero) I never referred to anything as a neutral. It was always ground. I don't even know why I'm used to referring to building wiring in terms of a neutral.

But I completely agree that putting the word "ground" in every conductor name is just asking for confusion. I think it's bad and I'm dumbfounded this is the best they've come up with.

Editted to add a little extra emphasis

[ February 15, 2005, 11:38 PM: Message edited by: physis ]
 
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