Isolated terminal bar

[Vertex]

Given:

1. Grounded conductors from the load side are connected to an isolated terminal bar mounted in a junction box (12x12x4 for arguments sake).
2. The isolated terminal bar is connected to an appropriately sized grounded conductor going back to the load center.
3. All associated ungrounded conductors run through the same raceway as the grounded conductors.

Does this pose any code violations?

 

[augie47]

not if they are isolated equipment grounds.
(if not, 250.148 would come into play)

 

[nakulak]

not if they are isolated equipment grounds.
(if not, 250.148 would come into play)

he said grounded conductors

 

[ceb58]

Not much different than a big wire nut

 

[TOOL_5150]

depending on the code cycle, you will need all the breakers handle tied.

~Matt

 

[don_resqcapt19]

Given:

1. Grounded conductors from the load side are connected to an isolated terminal bar mounted in a junction box (12x12x4 for arguments sake).
2. The isolated terminal bar is connected to an appropriately sized grounded conductor going back to the load center.
3. All associated ungrounded conductors run through the same raceway as the grounded conductors.

Does this pose any code violations?

I don't think that it is a violation of the current code rules, however the code making panels do not agree. They say that the use of a "common grounded" conductor, other than with a single multiwire circuit, is a code violation.

 

[nakulak]

I don't think that it is a violation of the current code rules, however the code making panels do not agree. They say that the use of a "common grounded" conductor, other than with a single multiwire circuit, is a code violation.

could you please cite the code reference ?

 

[cadpoint]

Not much different than a big wire nut

That or a terminal Block, I frankly couldn't get past that thought but since you stated that, for me its usually one to one per circuit - back home, YES.

Truly, I couldn't get past the terminal block thought, You Found it! I was wonder how long it'd take!

 

[dbuckley]

depending on the code cycle, you will need all the breakers handle tied.

And does this not also depend on if all the hots are fed from the same bar (trying hard to avoid the word 'phase'), so if there is no voltage between the hots then it isn't a MWBC and is (incorrectly, in my view) frowned upon, whereas if there is voltage between them its a MWBC and thus subject to MWBC provisions.

Electrically, this is trivial: as long as the common neutral conductor is appropriately sized, it is a safe circuit arrangement. But the NEC is making a mountain out of this electrically simple requirement by trying to avoid the need for calculations and just have simple yes/no rules.

 

[don_resqcapt19]

could you please cite the code reference ?

As I said, I don't think it is a code violation...yet..it will be in the 2011 code. The code panels say that the specific permission found in 215.4 and 225.7 act to prohibit all other uses of a common neutral.

 

[hurk27]

I have always figured 210.4(A) would come into play with this?:-?

This would be kind of like doing a service up grade and using the existing panel as a junction box, where one would leave the old neutral bar intact, and just feed it with a full sized neutral along with the branch circuit conductors to the new panel.
I was always told this was creating a MWBC, of many circuits and couldn't be done because of 210.4(A)

I think we debated this way back, but not sure if it was before the 2003 changeover or not

 

[hillbilly]

This thread has got me scratching my head.

What is the difference between the installation that the OP described and a simple feeder panel supplied with a full size neutral? (As far as the grounded circuit anyway).

He said that it was "appropiately" sized.
To me that means it is large enough to handle any load that may be imposed on it.

Maybe I don't understand the question.

steve

 

[jim dungar]

This is a common method with "column width" panelboards.
These panels are designed to fit into the web of a steel support column. The neutral and ground terminations are made at a terminal strip in a junction box mounted above the panel. Only the ungrounded conductors are run down the column, because both the feeder and branch conductors are run in the same raceway there is no problem with inductive heating.