Parallel Conductors Through Nipples

[rltomkinson]

I have three sets of 600's in a steel wireway from an enclosed breaker to a new 1200A ATS. I know that in the wireway the conductors have to be grouped together with one conductor per phase. My question is when they leave the wireway. They will be going through short nipples into the ATS. It would be a lot easier and look better if we ran each phase through a separate nipple as opposed to continuing the groups through each nipple. Is there anything in the code that would prohibit this? I am not seeing anything but that doesn't mean there is something there. Thanks.

 

[wwhitney]

I have zero practical experience on how to arrange things, but the relevant rules in the NEC are in 300.3(B).

Isophase is certainly not allowed with steel enclosures and separate steel nipples between them. But by my reading 300.3(B)(3) would allow you to cut a single rectangular (say) port in each enclosure, fabricate some aluminum (or other non ferrous metal) closure plates, and run aluminum (or other non ferrous) nipples between the two closure plates. That way with respect to the ferrous enclosures, all the conductors are running through a single hole.

Cheers, Wayne

 

[LarryFine]

Nipples would have the same induction issues as longer raceways.

 

[jaggedben]

I have three sets of 600's in a steel wireway from an enclosed breaker to a new 1200A ATS. I know that in the wireway the conductors have to be grouped together with one conductor per phase.

What code section is that?

My question is when they leave the wireway. They will be going through short nipples into the ATS. It would be a lot easier and look better if we ran each phase through a separate nipple as opposed to continuing the groups through each nipple. Is there anything in the code that would prohibit this? I am not seeing anything but that doesn't mean there is something there. Thanks.

As others have said, you have to group them. 300.20

 

[infinity]

Just run the wireway into the ATS.

 

[don_resqcapt19]

What code section is that?
...

376.20 Conductors Connected in Parallel
Where single conductor cables comprising each phase, neutral, or grounded conductor of an alternating-current circuit are connected in parallel as permitted in 310.10(G), the conductors shall be installed in groups consisting of not more than one conductor per phase, neutral, or grounded conductor.

 

[infinity]

What is the definition of a cable? I don't consider a single conductor cable to be same thing as a single conductor.

376.20 Conductors Connected in Parallel
Where single conductor cables comprising each phase, neutral, or grounded conductor of an alternating-current circuit are connected in parallel as permitted in 310.10(G), the conductors shall be installed in groups consisting of not more than one conductor per phase, neutral, or grounded conductor.

 

[don_resqcapt19]

What is the definition of a cable? I don't consider a single conductor cable to be same thing as a single conductor.

It is my understanding that single conductors with an extra jacket are single conductor cables. There was a change related to that term made in Article 392 for the 2023 code. The substantiation said

This change is recommended to bring in alignment with the changes that took place to Section 392.10- Uses Permitted in the 2020 NEC Revision Cycle. With the new statements that permit single insulated conductors 1/0 and Larger in cable trays like their close but different cousins Single Conductor Cable. While many folks believe they are the same they are not. So enlight of the changes in the 2020 NEC to permit something many have been already doing for decades (that's permitting conductors 1/0 and Larger in Cable Trays) this move aligns with the statements in 392.10.

but did not really explain what the difference may be.

 

[Tulsa Electrician]

I have three sets of 600's in a steel wireway from an enclosed breaker to a new 1200A ATS. I know that in the wireway the conductors have to be grouped together with one conductor per phase. My question is when they leave the wireway. They will be going through short nipples into the ATS. It would be a lot easier and look better if we ran each phase through a separate nipple as opposed to continuing the groups through each nipple. Is there anything in the code that would prohibit this? I am not seeing anything but that doesn't mean there is something there. Thanks.

The only time I have seen same phase in one raceway as you describe was an open bottom ran in PVC.
I do believe I recall something about cutting a slot between opening if not an open bottom.

Could 300.20 (B) be used if ran using PVC.

 

[synchro]

What is the definition of a cable? I don't consider a single conductor cable to be same thing as a single conductor.

It is my understanding that single conductors with an extra jacket are single conductor cables.

Yes, it seems that the term "single conductor cable" is associated with having an extra jacket and also having finer stranding than building wire, often with a "rope lay" at least in the larger sizes. As an example, there are single conductor Type W cables.

 

[rltomkinson]

Thanks everyone for the responses. We went ahead and grouped them one conductor per phase in the nipples.