Neutral for a 120/208y 300 amp service

[delectric123]

I am installing a 120/208y 300 amp breaker panel. the service conductors are 300 MCM Cu with an current rating of 285 amps without derating. As, of right now, the loads are 3 - 20 HP 3 ph. pumps, and a few lights and a few outlets. i'm sure i definitely don't need to count the neutral as a CCC, but can i downsize it? By how much? Whats the code reference to it?

 

[david]

230.42 Minimum Size and Rating.

220.61 Feeder or Service Neutral Load.
(A) Basic Calculation.

(B) Permitted Reductions. A service or feeder supplying the following loads shall be permitted to have an additional demand factor of 70 percent applied to the amount in 220.61(B)(1) or portion of the amount in 220.61(B)(2) determined by the basic calculation:

 

[kwired]

In general it only needs sized to the maximum calculated imbalanced current it will carry.

In no case can it be smaller than the GEC as mentioned in 250.24(C) for services.

For feeders or branch circuits it can not be smaller than the required EGC see 215.2(A)(2) for feeders.

 

[delectric123]

so i could probably get by with a 2 AWG Cu for a neutral?

 

[texie]

so i could probably get by with a 2 AWG Cu for a neutral?

Yes, #2 CU would be minimum in your case per Table 250.66 even if you have zero neutral load.