400A service, 2 -200A UG feeder neutral size

[benmin]

400A commercial service on a backboard. 2 200A feeders going to buildings which is run underground. Can you adjust the neutral on the feeders? 250-250-250-2 XHHW (hard piped all the way) or 250-250-3/0 triplex with copper THWN for EGC? (direct burial at the end entering the disconnect)?

 

[iwire]

400A commercial service on a backboard. 2 200A feeders going to buildings which is run underground. Can you adjust the neutral on the feeders? 250-250-250-2 XHHW (hard piped all the way) or 250-250-3/0 triplex with copper THWN for EGC? (direct burial at the end entering the disconnect)?

Yes you can reduce the neutral per 220.61



If the inspector feels these are seperate structures you will be limited to one feeder.

 

[petersonra]

have you looked at 220.61?

 

[benmin]

Thank you gentlemen, 220.61 was eluding me