NEC neutral requirements for medium voltage

[mstucky]

Does the NEC spell out neutral requirements for single-phase applications at medium voltage? My experience with MV up till now has been limited to 3-phase, 3-wire, and I'm having trouble finding where the code discusses neutral requirements.

Here is the scenario: We need to feed a 7200V-120/240V pad mount transformer from a 12470V grounded-wye system. It was suggested that this could be done using one phase conductor and a ground (no neutral). Coming from a background of working primarily with low voltage, this does not sound valid to me. However, I'm having a tough time backing up my intuition with the code.

Your insight would be appreciated.

 

[mstucky]

After doing some more digging, I think this situation is covered in 250.180 and 250.184 (2014 NEC). My understanding from this is that a neutral conductor IS required; However, it seems that in a multi-grounded neutral system [250.184(C)] no EGC is required, so the suggestion that we could use one phase conductor and a ground may have just been a mix up in terminology between neutral/ground.

I believe if we have one 15KV-rated phase conductor and one 600V-rated neutral conductor (both sized for the load), that we should be good, provided we ground the neutral at the new transformer. Thoughts?