Branch feeder to outbuildings

[PCBERRY]

A facilties outbuilding requires a 50 amp 480 volt feeder to support a 30 kva transformer and associated low side panel. Since this is a seperate building from the primary building and service there is a disconnect at the outbuilding ahead of the transformer.
The electrical engineer calls out for 4 number 6cu plus appropriate ground and bonds neutral and ground at the disconnect.
Since the transformer does not require a neutral does the code require this be pulled out to the outbuilding?

 

[raider1]

If a grounded conductor is not needed at the separate structure and a properly sized EGC is run then you aren't required to run a grounded conductor to the separate building.

On a side note, the 2008 NEC has eliminated 250.32(B)(2) and now does not allow the use of the grounded conductor for bonding at a separate structure, you are now required to run an EGC to ever separate structure.

Chris