Insulated neutral bar in wireway/trough legality

[Sra328]

I am on the road so do not have my code book readily available and looking for some assistance.
Context: Currently have a large project underway with several lighting control panels per floor across 5 different stories of the building.
Engineers have 8-10 switch legs on 1 branch circuit due to the intricacy of the spaces being lit.
All control panels have feed thru relays.
All rooms are laid out pretty typical with panelboard on left, relay panel on right, 2” gunners up to a trough/wireway with switch legs entering the top of the trough, and the branch circuit hot and neutral passing from the panel up to trough and back down into the relay panel.
Have had some back and forth on the legality of an insulated neutral bar in the wireway to connect all the grounded conductors of the switch legs to the grounded
Conductor from the panel, in order to avoid multiple neutral splices per circuit.
The question being: Is an insulated neutral bar installed “exposed” within a wireway a violation of the NEC? One of my journeymen is adamant that the neutral connections must be insulated to some degree (wirenut/wago/terminal blocks). I disagree, but would appreciate some input from folks with a code book at hand.
The neutral/grounded conductor of the circuit will still be contained within the same conduit as the ungrounded conductor from origin at panelboard to terminations at the relay panel.

 

[augie47]

Seemingly a violation of 200.4(A)'=
(A) Installation. Neutral conductors shall not be used for
more than one branch circuit, for more than one multiwire
branch circuit, or for more than one set of ungrounded feeder
conductors unless specifically permitted elsewhere in this Code.

and 408.41
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

 

[jaggedben]

I swear at some point there was some kind of exception for an auxiliary gutter adjacent to the panel, but I can't find it right now.

 

[tom baker]

An auxiliary gutter and wireway are not the same. Different rules for each.

 

[jaggedben]

An auxiliary gutter and wireway are not the same. Different rules for each.

Agreed, I didn't think it likely applied to the OP's installation. But does that exception still even exist?

 

[jap]

If the relay panel had a single OCPD that would cover the load of all the circuits needed that could be hit with a feeder, and, the individual branch circuit OCP devices originated in the relay panel, then, it probably would have a common neutral bar inside the relay panel for all the branch neutrals to land on.

Without that, the wiring to the relay panel is genrally treated as nothing more than a glorified multi pole contactor.

I'd be thinking about some dinrail and insulated terminal blocks to land the branch circuit and field neutrals on.

JAP>

 

[Sra328]

Seemingly a violation of 200.4(A)'=
(A) Installation. Neutral conductors shall not be used for
more than one branch circuit, for more than one multiwire
branch circuit, or for more than one set of ungrounded feeder
conductors unless specifically permitted elsewhere in this Code.

and 408.41
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

I don’t think I was clear/concise enough last night. It was too late to be writing up a post.
There is no situation where the neutral is being used for more than 1 circuit. This would be similar to 1 circuit feeding a 4 gang switch box with 4 switch legs. In that case you would connect all grounded conductors in 1 wire nut/wago/whatever floats your boat. In my circumstance there are 9-10 switch legs that all need to connect to the same grounded conductor. Which ties into second article you mentioned.

The grounded conductor of the branch circuit does terminate in its own terminal at the panelboard where it originates.
It is the legality of connecting the other end of that grounded conductor to an insulated neutral bar in a wireway/trough in lieu of multiple splices per circuit in the trough.

 

[Sra328]

If the relay panel had a single OCPD that would cover the load of all the circuits needed that could be hit with a feeder, and, the individual branch circuit OCP devices originated in the relay panel, then, it probably would have a common neutral bar inside the relay panel for all the branch neutrals to land on.

Without that, the wiring to the relay panel is genrally treated as nothing more than a glorified multi pole contactor.

I'd be thinking about some dinrail and insulated terminal blocks to land the branch circuit and field neutrals on.

JAP>

The relay panel does not have the ocpd within. Just a glorified contact as noted.
Din rail and term blocks with jumpers was my final decision, however I am still genuinely curious if there is any code article that would have prohibited an insulated neutral bar.

 

[jaggedben]

That clears things up.

I don't think there is a clear prohibition on an 'exposed' neutral bar for making splices in a wireway, so long as it's insulated from the wireway (obviously).

I would just not use bare EGCs in the same wireway, to avoid an accidental N-G bond.

 

[jap]

That clears things up.

I don't think there is a clear prohibition on an 'exposed' neutral bar for making splices in a wireway, so long as it's insulated from the wireway (obviously).

I would just not use bare EGCs in the same wireway, to avoid an accidental N-G bond.

There may not be a prohibitiion of an exposed neutral bar for making splices used in the right setting , but, there is on combining all of the individual branch circuit neutrals together on a common bar.

I think Augie nailed it in post #2.

JAP>

 

[jaggedben]

There may not be a prohibitiion of an exposed neutral bar for making splices used in the right setting , but, there is on combining all of the individual branch circuit neutrals together on a common bar.

I think Augie nailed it in post #2.

JAP>

The OP has clarified that there is only one branch circuit per wireway and relay box. Post #2 was a misunderstanding of the question. There is no prohibition on tapping a branch circuit to multiple relays and fixtures.

 

[jap]

The OP has clarified that there is only one branch circuit per wireway and relay box. Post #2 was a misunderstanding of the question. There is no prohibition on tapping a branch circuit to multiple relays and fixtures.

Ooops,, I see that now.

In that case the insulated neutral bar would be nothing more than a connection point.

Sorry,

JAP>

 

[augie47]

As long as there is just one branch circuit feeding the neutral bar and multiple conductors tie to that bar,. I agree, no problem...no different from a wirenut. More than one branch to the neutral it would be (unless its a MWBC)

 

[MTW]

Siemens column width panel board comes with an extended wire way up to the top, inside the column flanges, and then has a connection box at the top with an insulated neutral bar within. Un-grounded branch circuit conductors originate at the panelboard near the bottom of the column. Main grounded conductor usually originates from a transformer above, and runs down to the connection box, isolated neutral bar, near the top of the column.

Branch circuit conductors originate at both the top connection box and bottom panelboard of the wire way, and exit at the connection box at the top.

 

[jap]

Siemens column width panel board comes with an extended wire way up to the top, inside the column flanges, and then has a connection box at the top with an insulated neutral bar within. Un-grounded branch circuit conductors originate at the panelboard near the bottom of the column. Main grounded conductor usually originates from a transformer above, and runs down to the connection box, isolated neutral bar, near the top of the column.

Branch circuit conductors originate at both the top connection box and bottom panelboard of the wire way, and exit at the connection box at the top.

What is run between the neutral bar at the top connection box and the neutral bar located at the panel?

JAP>

 

[MTW]

@jap There is no neutral in the panelboard. It runs from a ceiling mounted separately derived system transformer, to the connection box at the top of the column. Neutral bar is relocated from the panelboard to the connection box at the top. There is no space for the neutral bar in the panelboard, its only 7-1/2” wide, to fit inside the 8” column. Connection box at the top of the column has ample room for the bar and it’s conductors.

The configuration is designed to put the overcurrent devices where accessible on the plant floor, and put the conduit and wiring connections in a box near the ceiling, where there is room to install and distribute them into the space. Inside the column protects the board. From most physical damage that is likely to happen, down near the floor.

 

[Sra328]

As long as there is just one branch circuit feeding the neutral bar and multiple conductors tie to that bar,. I agree, no problem...no different from a wirenut. More than one branch to the neutral it would be (unless its a MWBC)

Agreed and appreciate your input. More of a hindsight question I was curious about as I decided on a different route but it was brought up again in a discussion yesterday.
It ended up costing less to buy din rail, ut-4 term blocks, end stops, push in jumpers vs. Insulated neutral bars. This allowed us to build separate sections to make sure we separated circuit neutrals where more than 1 branch circuit was used in some of the relay panels.