ECN Forum Forums Code Related Discussion NEC & other Code issues Neutral required?

4160 over head to pole mounted transformer. Feeder NOT Service. Secondary 480/277 . Run dn pole with 3 hots & Ground sized by 250.66 .
I say must be 3 hots plus Neutral.
Need neutral to be able to ground at building.
Remember NOT SERVICE conductors , Owner ownes 4160 pole line.
Whatca Think??
Please give code Sections Yoopersup