Thread: Neutral bus question.

I seem to remember a thread were 2 neutral conductors terminated at the same point under one lug. I forget how the string proceeded.
Seeing there are breakers that accept two conductors in a service or remote panel, is it acceptable to terminate two neutral wires on a single screw or lug in a neutral bus?
Much thanks.
Looking forward to reading the answer/s.

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Originally Posted by ROBERT YOUNG

... is it acceptable to terminate two neutral wires on a single screw or lug in a neutral bus?

No.

Joe E Brown
Charlie Chaplin
Groucho Marx
Abbott and Costello
(said I had to have characters minimum)

Originally Posted by Jerry Peck

No.

Joe E Brown
Charlie Chaplin
Groucho Marx
Abbott and Costello
(said I had to have characters minimum)

I think Lon Chaney would have covered that.

JP is correct, more specifically NEC 2014:

408.41 Grounded Conductor Terminations.
Each grounded conductor shall terminate within the panelboard in an individual terminal that is not also used for another conductor.

Originally Posted by Derek Guridi

JP is correct, more specifically NEC 2014:

Much thanks.
I was looking for something codified.

I understand the concept. One circuit conductor per neutral termination point.
I am not disputing that.

Could some explain the Exception: (Parallel conductors.) rule.
Would this be two (2) conductors under one breaker/circuit?
There are two breaker manufacturers that product breakers that can be tapped on the terminal two times. Would those conductors be considered parallel?
If not, please explain the term, (Parallel conductors.)

Much thanks as always.

Parallel conductors would originate at A source (a meter base or service disconnect for instance) and then be routed to A termination (the main lugs at a distribution panel). The conductors must be electrically joined.

Each conductor would need to be connected to it's own lug at the service disconnect and at the distribution panel OR the lugs would need to be labeled & listed for more than one conductor. Parallel conductors should be 1/0 minimum.
Two conductors connected to a breaker would not be in parallel unless they follow the above. I have not seen standard branch circuit breakers in a residential system that would accept a 1/0 conductor.

http://www.ecmag.com/section/systems...ected-parallel
for your reading enjoyment

408.41 Grounded Conductor Terminations. Each grounded
conductor shall terminate within the panelboard in an individual
terminal that is not also used for another conductor.

"The intent of this requirement is to ensure that the grounded (neutral) conductor of a multiwire branch circuit is not momentarily disconnected, which could result in the destruction of electrical equipment and fires from overvoltage."

Originally Posted by Roy Lewis

408.41 Grounded Conductor Terminations. Each grounded
conductor shall terminate within the panelboard in an individual
terminal that is not also used for another conductor.

"The intent of this requirement is to ensure that the grounded (neutral) conductor of a multiwire branch circuit is not momentarily disconnected, which could result in the destruction of electrical equipment and fires from overvoltage."

Hate to nit pick, but I will.

When quoting someone it is generally required/polite to cite the source as to give the original author credit and also allow one to decide on the validity/credibility of the author/source. The parentheses (quote) punctuation is a good step, but a citation is really a must IMO. Sorry if I sound priggish, but I am very sensitive on copywrite/plagiarism issues.

I will guess this your source or close; words there are verbatim to your quote.

https://www.mikeholt.com/videodispla...hp?pageid=2112

I didn't remember where I got it from.
It was just in my narrative collection.

Originally Posted by Derek Guridi

Hate to nit pick, but I will.

When quoting someone it is generally required/polite to cite the source as to give the original author credit and also allow one to decide on the validity/credibility of the author/source. The parentheses (quote) punctuation is a good step, but a citation is really a must IMO. Sorry if I sound priggish, but I am very sensitive on copywrite/plagiarism issues.

I will guess this your source or close; words there are verbatim to your quote.

https://www.mikeholt.com/videodispla...hp?pageid=2112

Originally Posted by Alton Darty

Parallel conductors would originate at A source (a meter base or service disconnect for instance) and then be routed to A termination (the main lugs at a distribution panel). The conductors must be electrically joined.

Thanks, Alton.
I know I am stretching codified.
My example is not metering point or service disconnected.
Think of, A source as the service panel break.
The A source accepts two cables/conductor.
As you expressed, the conductors must be electrically joined and they are a the breaker.

Think of why the code separates neutral conductors per bus terminal.
If 2 conductors served one breaker on a circuit, why could the conductors not share a neutral termination point.

Thanks for your patients.

Originally Posted by ROBERT YOUNG

Think of why the code separates neutral conductors per bus terminal.
If 2 conductors served one breaker on a circuit, why could the conductors not share a neutral termination point.

Let's simply the thought process down to the basics of what happens:

- Two conductors at one breaker, each conductor is a part of one circuit off one overcurrent device.
- - Remove (switch off) one conductor.

- Two conductors at one neutral termination, each conductor is a separate circuit off two overcurrent devices.
- - Remove ( switch off ) one conductor.

The first scenario results in switching off one 'hot' conductor.

The second scenario results in switching off one neutral conductor.

Should the neutral be switched?

Originally Posted by Jerry Peck

Let's simply the thought process down to the basics of what happens:

That is what I have been attempting to do. Many scenarios. That is why I am still at the thread.

Originally Posted by Jerry Peck

- Two conductors at one breaker, each conductor is a part of one circuit off one overcurrent device.
- - Remove (switch off) one conductor.

To remove one conductor the breaker requires to be turned/switched off.
Both conductor are deenergized.

Originally Posted by Jerry Peck

- Two conductors at one neutral termination, each conductor is a separate circuit off two overcurrent devices.
- - Remove ( switch off ) one conductor.

I disagree.
Two conductors at one neutral termination, each conductor an extended circuit off "one" overcurrent devices.

The breaker tapped at the terminal saddle to extend the circuit.
Square D breakers and Cutler Hammer manufacture overcurrent devices/breakers rated for two wire connections/conductors. This allows the circuit to be extended.

Originally Posted by Jerry Peck

The first scenario results in switching off one 'hot' conductor.

I disagree. It switches of both conductors. To maintenance a circuit, you switch off the breaker therefor deenergizing both conductors. If one conductor was removed from the breaker that is capable of accepting two conductors to abandon the circuit extension, that would be another story. The electrician would remove the one neutral as well.

Originally Posted by Jerry Peck

The second scenario results in switching off one neutral conductor.

Should the neutral be switched?[/QUOTE]
Neutrals should not be switched.

I do not mean to be flogging a dead horse but I still do not see why two conductors utilizing one breaker can not terminate at one neutral termination point if the conductors are not separated at the break for maintenance or to abandon one part of the circuit.

Is my hypothesis correct?

Robert,

Go back through my post, except instead of thinking about something I didn't say, keep with what I did say.

I.e. I didn't say anything about turning a breaker off, only about removing a conductor. And I made sure to connect the idea that removing a conductor is essentially the same as switching the conductor off.

Then I tied it together with switching a 'hot' off (which is okay) and switching a neutral off (which is not okay).

Now what do you get when you re-read it?

Originally Posted by Jerry Peck

Robert,

Go back through my post, except instead of thinking about something I didn't say, keep with what I did say.

Originally Posted by Jerry Peck

I.e. I didn't say anything about turning a breaker off, only about removing a conductor. And I made sure to connect the idea that removing a conductor is essentially the same as switching the conductor off.

I understand.

Originally Posted by Jerry Peck

Then I tied it together with switching a 'hot' off (which is okay) and switching a neutral off (which is not okay).

Got it.

Originally Posted by Jerry Peck

Now what do you get when you re-read it?

Why one conductor is required per neutral bus termination.
Much appreciated.

I see the point in the discussion, but get more confused by trying to read the JP/RY stuff, no offense.

Removing a neutral conductor while a circuit is energized is foolhardy, we all agree.
I believe the logic behind the rule is that while removing the correct neutral where two neutrals were double-lugged, the other neutral might be pulled out. Alternately, he could pull the wrong neutral, as they are not easily identified in the field. If the electrician failed to de-energize that second circuit, bad things could happen.

FYI, in Canada, there is a 3rd brand of breakers that allow double taps. Schneider, owners of Square D and others, makes a Schneider panel that uses HO-style breakers. The Schneider breakers have double jaws just like the Square D type.

Originally Posted by John Kogel

I see the point in the discussion, but get more confused by trying to read the JP/RY stuff, no offense.

Removing a neutral conductor while a circuit is energized is foolhardy, we all agree.
I believe the logic behind the rule is that while removing the correct neutral where two neutrals were double-lugged, the other neutral might be pulled out. Alternately, he could pull the wrong neutral, as they are not easily identified in the field. If the electrician failed to de-energize that second circuit, bad things could happen.

FYI, in Canada, there is a 3rd brand of breakers that allow double taps. Schneider, owners of Square D and others, makes a Schneider panel that uses HO-style breakers. The Schneider breakers have double jaws just like the Square D type.

Thanks for chiming in, John.
I am sure/certain others have asked the same question but let the thread play out.

Originally Posted by John Kogel

I believe the logic behind the rule is that while removing the correct neutral where two neutrals were double-lugged, the other neutral might be pulled out. Alternately, he could pull the wrong neutral, as they are not easily identified in the field. If the electrician failed to de-energize that second circuit, bad things could happen.

From the NEC Handbook: (not typing all of it, too long, but enough to show what it says, which is still a lot to type)
- (blah, blah, blah) The use of a single termination point within a panelboard to connect more than one grounded conductor to connect a grounded conductor and an equipment grounding conductor can be problematic when it is necessary to isolate a particular grounded conductor for testing purposes. For example, if the grounded conductors of two branch circuits were terminated at a single connection point and it were necessary to isolate one branch circuit for the purposes of troubleshooting, the fact that the circuit not being tested remained energized could create an unsafe working condition for service personnel disconnecting the grounded conductor of the circuit being tested. (blah, blah, blah)