Question about neutral requirements on overhead wiring under nec 2008

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I could use some understanding of the possible code changes for NEC2008. At the moment on a military base there is single phase 4160 feeding a single phase pole mounted transformer with just a phase and neutral wire on the primary. I have been asked to add a third building to the secondary of the transformer. The original two buildings are fed with a messenger wire, and two insulated conductors. (All conductors are crimped together in seperate splices at the end of the transformer pigtail wiring) It appears from the photo of the transformer (telephoto) that the two insulated conductors are each fed from two seperate lugs off the transfomer and the messenger wire is connected to the neutral lug. In addition the transformer case is tied to the pole ground wire with in turn is connected to the grounding electrode and pole guy wire. My question is should the third building which is new, be connected as the existing buildings are with three conductors (two insulated, one messenger) or should it have four conductors (three insulated for the phases and neutral) and the messenger wire used as an EGC.If this is the case should the messenger wire also be tied into the grounding wire and ground electrode on the pole. Thanks
 
I am assuming the system on the base is considered the serving electric utility and you will be following the NESC until you enter the building.

The existing installation is just fine and the messenger is actually the neutral. Everything in front of the service equipment is to be grounded to the system neutral. Just install a service drop to the new building and do not install a grounding conductor (the neutral is both the grounded and grounding conductor). Install the new service as a normal service would be installed in accordance with Article 230. :smile:
 
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