Can't find actual codes against this

[david]

If you could, Please take this drawing , leave both neutrals in place in the field , but combine circuits 1&7, 3&9 and 5&11 on circuits 7,9 &11 with (2) return neutrals to the panels neutral bar and please repost.

I'm still not completely satisfied with this set up.

Something about having the (2) neutrals returning to the panel just doesn't seem right, even though the handle tie would kill any return on either neutral.

JAP>

Jab this would not meet the definition of a multi-wire branch circuit and would be a parallel neutral for circuit 7, 9 and 11.

 

[kwired]

Jab this would not meet the definition of a multi-wire branch circuit and would be a parallel neutral for circuit 7, 9 and 11.

You have two neutral conductors that are parallel to one another, but they are each carrying separate current. They are not "in parallel" and sharing a portion of same current. Both are carrying current from more then one ungrounded conductor though, which makes them at least a portion of a MWBC.

 

[jap]

Jab this would not meet the definition of a multi-wire branch circuit and would be a parallel neutral for circuit 7, 9 and 11.

From what I understand, this is what the OP has now since nothing was changed in the field.

JAP>

 

[jap]

K- wired is right, but, if the definition of a MWBC is worded for a "Single" return neutral on the "Branch Circuit" to the Neutral bar, that's not what the OP has.

And that's where the water gets muddy for me, not that I really care one way or the other.

Just seems odd and not the way I would have done it.

JAP>

 

[david]

A multi wire circuit has only one grounded (neutral ) connection to the system neutral

 

[david]

You have two neutral conductors that are parallel to one another, but they are each carrying separate current. They are not "in parallel" and sharing a portion of same current. Both are carrying current from more then one ungrounded conductor though, which makes them at least a portion of a MWBC.

If both neutrals land at the panel neutral buss they may not electrically make any difference functionally but the circuit would not meet the definition of a multi wire circuit.

How would you define the circuit?

 

[jap]

A multi wire circuit has only one grounded (neutral ) connection to the system neutral

I may be wrong, but, I think K-wired is saying they do have that, where the 2 neutral return wires land on the neutral bar in the panel.

JAP>

 

[david]

You have two neutral conductors that are parallel to one another, but they are each carrying separate current. They are not "in parallel" and sharing a portion of same current. Both are carrying current from more then one ungrounded conductor though, which makes them at least a portion of a MWBC.

Are they still not in parallel to the multi wire circuit itself? parallel conductors always carry a portion of the total current of a circuit.

They are however not splice together at each end, at least not before passing through a load

 

[kwired]

Art 100 Definitions:

Branch Circuit, Multiwire.


A branch circuit that consists of two or more ungrounded conductors that have a voltage between them, and a grounded conductor that has equal voltage between it and each ungrounded conductor of the circuit and that is connected to the neutral or grounded conductor of the system.

The two grounded conductors come together at the panel neutral bus- which is the system grounded conductor.

The ungrounded conductors (in the OP's situation) are also multiple conductors leaving the breaker(s), but is still just one branch circuit through one overcurrent device. If you ran 3 ungrounded and 1 grounded as short a distance as physically possible then spliced in to two directions per lead giving you 6 ungrounded and 2 grounded conductors (just like they attempted to do in OP) you still have one MWBC. You still have one MWBC if you split the original four conductors into 100 directions.

ADD: IMO if you sent out the six ungrounded conductors (but connected to three overcurrent devices - one each phase) and returned with 5 ungrounded conductors leaving you sharing one of the neutrals between two of the ungrounded conductors - you still have a MWBC. Only if you return six neutrals and don't share it with multiple ungrounded conductors would it not be a MWBC, even if you put a handle tie on it.

 

[kwired]

Are they still not in parallel to the multi wire circuit itself? parallel conductors always carry a portion of the total current of a circuit.

They are however not splice together at each end, at least not before passing through a load

But with a true "parallel conductor" the current has a choice of which segment of the parallel conductor to take. In that image there is no alternate parallel paths at any point, current passing through one load must return through the neutral conductor it connects to - it can't take one or the other, they would have to be tied together at both ends for that to be possible.

 

[jap]

if you sent out the six ungrounded conductors (but connected to three overcurrent devices - one each phase) and returned with 5 ungrounded conductors

What ? :?

JAP>

 

[david]

If ground fault protection (3-pole) was added to this circuit, the circuit protection would trip unless the neutral one and seven landed on the breakers neutral terminal and a single pigtail from the breakers supply neutral landed on the panel neutral buss.

With both neutral 1 and 7 tied to a multi wire circuit and landing separately onto the panels neutral buss i do not know how to define this circuit.

I really don't have much more to add constructively to the discussion

 

[kwired]

If ground fault protection (3-pole) was added to this circuit, the circuit protection would trip unless the neutral one and seven landed on the breakers neutral terminal and a single pigtail from the breakers supply neutral landed on the panel neutral buss.

With both neutral 1 and 7 tied to a multi wire circuit and landing separately onto the panels neutral buss i do not know how to define this circuit.

I really don't have much more to add constructively to the discussion

Do you call it a MWBC if we tied those two neutrals together just an inch or two away from the panelboard neutral bus and only landed one common "wire" on the bus?

I do not see "neutral bus" anywhere in the definition of "Branch circuit, multiwire". It does say "neutral or grounded conductor of the system" which is exactly what the neutral bus in the panel is a part of.

 

[jap]

The same could be said if you had a single pole circuit going out feeding 2 individual receptacles where each receptacle had it's own neutral back to the neutral bar in the panel.

No, the return current on receptacle #1 would not return on the Neutral from #2 receptacle,
and,
No, the return current on receptacle #2 would not return on the Neutral from #1 receptacle,

If we were to put a GFI ahead of this circuit, we would have to take both return neutrals and land them on the neutral terminal of the GFI breaker, but, since the terminal is probably only rated for 1 conductor, we'd probably have to take the 2 neutrals off of the neutral bar, wirenut the 2 neutrals together in the panel, and bring only 1 conductor to the neutral termination on the breaker.

Dad Gum those maintenance guys for making us have to think about this so much.

JAP>

 

[kwired]

The same could be said if you had a single pole circuit going out feeding 2 individual receptacles where each receptacle had it's own neutral back to the neutral bar in the panel.

No, the return current on receptacle #1 would not return on the Neutral from #2 receptacle,
and,
No, the return current on receptacle #2 would not return on the Neutral from #1 receptacle,

If we were to put a GFI ahead of this circuit, we would have to take both return neutrals and land them on the neutral terminal of the GFI breaker, but, since the terminal is probably only rated for 1 conductor, we'd probably have to take the 2 neutrals off of the neutral bar, wirenut the 2 neutrals together in the panel, and bring only 1 conductor to the neutral termination on the breaker.

Dad Gum those maintenance guys for making us have to think about this so much.

JAP>

Correct - but you still consider there to be only 1 branch circuit in that situation.


Run a 400 amp feeder with 500 copper on A phase, parallel 4/0 alumium on B phase, parallel 3/0 copper on C phase, and three parallel 1/0 aluminum as the neutral - you still have just one feeder, yes?

 

[jap]

Correct - but you still consider there to be only 1 branch circuit in that situation.


Run a 400 amp feeder with 500 copper on A phase, parallel 4/0 alumium on B phase, parallel 3/0 copper on C phase, and three parallel 1/0 aluminum as the neutral - you still have just one feeder, yes?

Yes, but lets try to stay focused K-Wired...

JAP>

 

[kwired]

Yes, but lets try to stay focused K-Wired...

JAP>

Sorry, a little bored today, since the ice storm has finally moved into my area, I planned to work in the office today, chatting here is much more fun then office work though

 

[lordofthisworld]

I am not sure I fully understand the configuration you are describing. It sounds like you originally had two MWBCs: 1-3-5 and 7-9-11. It also sounds like the loads previously served by 1, 3, 5, and 7 are now getting their power from circuit breaker #1. That much is OK. Finally, it also sounds like circuits 9 and 11 still comprise a MWBC, and that they still share the original neutral. That much is also OK. But I can’t envision what happened to the neutral connection at the receptacle originally fed from circuit 7.

There was a hot wire from circuit breaker 7 that landed on the hot side of a receptacle outlet (call it “receptacle #7”). There was a neutral wire that connected the neutral side of that receptacle to the neutral sides of the receptacle #9 and receptacle #11. From some point along the way, one neutral wire made its way back to the panel’s neutral bus. But if all the wiring changes were done inside the panel, then receptacle #7 still shares its neutral with receptacles 9 and 11. If that is the case, then even if circuit breakers 9 and 11 share a listed handle tie, any future work on one of these circuits would place the worker in danger, because the worker would not know that they also need to turn off circuit breaker #1. You would have a violation of 300.3(B).

Wouldn’t tying CKT’s 1,3,5,7 together sharing a neutral be a violation since CKT 1 and 7 share the same phase?

 

[GoldDigger]

Wouldn’t tying CKT’s 1,3,5,7 together sharing a neutral be a violation since CKT 1 and 7 share the same phase?

No, because the circuit originally on breaker 1 is now fed from breaker 7. As long as the load calculations are OK the fact that both circuits are connected to #7 is not, by itself, a problem.
If both 1 and 7 had been fully (or even just above half) loaded, it would indeed be a problem.