2-Wire, 120v circuit

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james wuebker

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Iowa
OK people, help me out. I was teaching 4 or 5 of my co-works about electrical things today and they asked me what do they call in a 2-wire, 120v circuit the white wire. I told them the answer and no one believed me. So I told them that I would write you here and I would show them what you guys answered. Maybe I told them the wrong answer.
Thanks!
Jim
 
Re: 2-Wire, 120v circuit

Well, it's not a neutral.

Roger
 
Re: 2-Wire, 120v circuit

Well, as we all know, it is not a "neutral".
By NEC definition it is a "grounded conductor".

We also know that in informal communication, many of us call it a "neutral".
It is important in formal communication, to use the correct terminology.
 
Re: 2-Wire, 120v circuit

Originally posted by hurk27:
It could be called the return conductor?
Click to expand...
But is it really in an AC circuit? ;)

Roger
 
Re: 2-Wire, 120v circuit

The white wire of a 2 wire circuit is not called a neutral conductor as we know it. It is the GROUNDED CONDUCTOR.

If the installation has 1 ungrounded conductor (hot, phase, energized conductor) installed with the grounded conductor, the white conductor is called the GROUNDED CONDUCTOR.
This could typically be an AC cable run up to a lighting fixture.

If the installation has 2 or more ungrounded conductors installed with the grounded conductor, the white conductor is called the NEUTRAL CONDUCTOR.
Typically a range circuit.
 
Re: 2-Wire, 120v circuit

Hello John,
If it is A/C then it would be the return conductor every other half cycle. :)

Roger
Click to expand...
 
Re: 2-Wire, 120v circuit

Funny answers.
OK, I told them that it was the grounded conductor. They said it was a neutral. I said in a 2-wire circuit the grounded conductor carries the same amount of current as the ungrounded conductor carries. I told them that the neutral, it carries the unbalanced current. Told them that you must have a 3-wire circuit to have a neutral conductor. Maybe they might start believing me more often.
Thanks everyone.
Bye now,
Jim
 
Re: 2-Wire, 120v circuit

On 3-wire corner grounded 3-phase the grounded conductor is NOT a neutral. It carries full load current. If the "neutral" bar in a disconnect switch is not rated for corner grounded operation it probably is junk.

There are also some applications such as most gasoline dispensers where all of the 120 volt circuits have to be on the same phase. This means that all the interior lights have to be on the other phase(s) to balance the load. This can make for some rather warm neutral bars if you are using a subpanel for the dispenser.

I also would not be surprised that some traffic light controller manufacturers say that you cannot have 120/240 volts in their control box, only 120 volts.
 
Re: 2-Wire, 120v circuit

Yes, I have heard the term "return" used incorrectly for the grounded conductor of a 2-wire ckt. - IMO, this is worse than calling it a "neutral".

It is usually used by DIY'ers who also frequently use terms like 110V. 220V.,440V. Or they may say things like "a white wire will not hurt you."

2002 NEC 200.7(C)(2) uses the term "return" to describe a "switchleg".
 
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