Service point locations on multi-building industrial complexes

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jtinge

Senior Member
Location
Hampton, VA
Occupation
Sr. Elec. Engr
We are an established research government installation with approximately 200 buildings on a campus style complex with many labs large medium voltage loads fed directly from substations. We connect to the local utility at 115 kV at our main substation and distribute power at 115 kv and 22 kV to 17 distribution substations from which we then distribute MV power to our facilities. We own and operate our distribution system downstream of the 115 kV utility connection. Historically we have treated our distribution system like a utility and have established service points at the unit substations serving each building for applying the NEC.

I am aware of several other DOE and DOD installations that establish service points in a similar fashion to us and operate their own distribution system like a utility. An example of one is below:

"2.2 Building Service Point Location
A. ....For xxxx facilities, use the following definitions for electrical utility and service or service point, based on the configuration of the service system:

1. Pad Mounted Transformer: The utility system includes the medium-voltage (13.2 kV) distribution system and the pad mounted transformer. The service point is at the low voltage (120/240V, 208Y/120V, or 480Y/277V) terminals of the pad-mounted transformer.

2. Secondary Unit Substation: The utility system includes the medium voltage distribution system, the unit substation medium-voltage switchgear, and the unit substation transformer. The service point is at the low voltage terminals of the secondary unit substation transformer. The secondary unit substation may be inside or outside the building.

3. Overhead Low-Voltage Utility Service: The utility system includes the medium voltage distribution system, the pole mounted transformer(s), and the low voltage service drop. The service point is at the building service entrance weatherhead (or equivalent).

4. Underground Low-Voltage Utility Service: The utility system includes the medium voltage distribution system, the pole mounted transformer(s), and the low voltage underground service lateral. The service point is at the line terminals of the first low voltage service disconnecting means. The low voltage service disconnect may be located on the utility pole, outside the building, or inside the building.

Footnote-Definitions of supply points are necessary because a utility company does not individually serve xxxx facilities. The xxx support services subcontractor serves the functions of a utility company, including operating and maintaining medium-voltage equipment up to the secondary terminals or the building supply transformers."

My concern is that continuing to define our own service points within our own distribution system seems to violate the NEC; however, to suddenly change our service point to the 115 kV utility connection at our main substation seems frot with unintended consequences. Service points at our existing facilities are no longer service points. The distribution system is now covered by the NEC, but not very well, especially for our 115 kV and 22 kV distribution circuits and substations.

Anyone have a similar multi-building complex with a customer-owned distribution system? How are you dealing with current NEC requirements as they apply to this type of system?
 
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