Transfer switch Neutral

[WirenutNH]

I have a question. We have been asked to install a 400 amp 120/208v 3 ph solid neutral transfer switch right next to the existing MCC. My plan is to load out of main to normal line on xfr switch, then from load out of xfr switch to existing load conductors in mcc. If I run all three hots into the xfr switch do I need to run the neutral with them into switch and back?

 

[StreamlineGT]

I would like to see the neutrals tied into the switch. Where else would you tie them together, in the switchgear? I'm not sure in terms of code requirements, but from an installation standpoint, the switch is the way to go. That way there is never any question as to what the neutrals are for. Is there any control neutrals that are fed from the switch neutral block?

 

[ceb58]

I would say it would be a violation not to bring them into the ATS

(B) Conductors of the Same Circuit.​

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All conductors ofthe same circuit and, where used, the grounded conductorand all equipment grounding conductors and bonding conductorsshall be contained within the same raceway, auxiliarygutter, cable tray, cablebus assembly, trench, cable, orcord, unless otherwise permitted in accordance with​

300.3(B)(1) through (B)(4).

 

[hurk27]

I would say it would be a violation not to bring them into the ATS

(B) Conductors of the Same Circuit.​

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All conductors ofthe same circuit and, where used, the grounded conductorand all equipment grounding conductors and bonding conductorsshall be contained within the same raceway, auxiliarygutter, cable tray, cablebus assembly, trench, cable, orcord, unless otherwise permitted in accordance with​

300.3(B)(1) through (B)(4).

Above in red
If this was true then dead end switches are also a violation?
a transfer switch is just that a switch, if the Neutral is not needed in the transfer switch then I see no problem, but if the feeders from the generator are landed first in the transfer switch then the neutral must also land in the TS, the problem is if the neutral is not routed with the ungrounded conductors and there is more then one raceway for each set of conductors then it would be a violation, if you run them in one raceway derating will kick in.

Conductors to a switch must return from the switch in the same raceway to the point they seperate and go there own way which at that point they need the neutral with them.

 

[bbaumer]

Have you looked to see if there is even a neutral run to the MCC?

MCC's are usually all motor load and oftentimes don't even have a neutral run to them. Control circuits are 208 or have a a control circuit transformer(s) in them for 120 or 24V.