oversized neutral for ATS switch

[anbm]

If we oversize neutral comes to ATS, what do we need to specify/change on ATS?

 

[ron]

It depends on why you oversized the neutral conductor. Was it for voltage drop or harmonics or ....

 

[anbm]

harmonic...

 

[nakulak]

If we oversize neutral comes to ATS, what do we need to specify/change on ATS?

the size of the lug (s) ?

 

[dbuckley]

If we oversize neutral comes to ATS, what do we need to specify/change on ATS?

The ATS neutral needs to be specified to (at least) the same current overrating that you've used to calculate your wire oversize. I dont know if you can order a mechanical ATS that way, but certainly you can order Cyberex four pole static switches with 200% neutral switching capability. If you cant get a overrated neutral ATS then you should upsize the ATS to match the neutral ($$$ - ouch!)

This annoyance is one of the reasons why my standard advice for ATSes is to use solid neutral with three pole switching wherever possible; only switch neutrals if you absolutely have to. An ATS dropping a phase is an annoyance, but dropping a neutral is very expensive...