What NEC requirements apply to a campus-style utility feed to a structure?

[pharouff]

Most of the time our responsibility ends 5 feet from the perimeter of the building; and beyond that point is the commercial utility's responsibility where the NEC does not apply. A utility power cable is considered a "service lateral" until it reaches the first overcurrent protection device where it becomes "premises wiring".

But sometimes we have to deal with a campus power distribution system, where some NEC requirements may apply to the incoming power service. For example, there are requirements in Articles 695.3 and 695.5 which appear to apply to campus-style complexes. Also, there are some who argue that the NEC applies anywhere past the utility meter: the entire campus.

Are power cables from campus substations to individual structures considered "premises wiring" or "service laterals"? Are they sized and installed per the NEC?

Do we need to size exterior campus utility substation transformers per the "NEC" peak demand load or per the "corporate experience" peak demand load similar to a typical utility company?

What if the campus has primary power generation facilities?

 

[iwire]

Are power cables from campus substations to individual structures considered "premises wiring" or "service laterals"? Are they sized and installed per the NEC?

It sure can be premises wiring, you need to determine where the service point is.

Do we need to size exterior campus utility substation transformers per the "NEC" peak demand load or per the "corporate experience" peak demand load similar to a typical utility company?

If they are on the customer side of the service point they must be sized per the NEC regardless of voltage or experiance.

For instance I used to work at a large multi building facility where the utility service ended at the property line and we owned all the distribution beyond that. The utility provided us with 4160 volts and we had to run that to several points around the property and transform it to 208 or 480 as needed.

 

[don_resqcapt19]

... Also, there are some who argue that the NEC applies anywhere past the utility meter: the entire campus. ...

It does, but the NEC does not do a very good job in covering those types of installations.

 

[jim dungar]

What if the campus has primary power generation facilities?

Simply owning generators does not make you a utility.
Even utility non-generation facilities need to follow the NEC.

 

[pharouff]

In article 90.2(A)(2), what is the definition of an INDUSTRIAL substation? The NEC Handbook explanation says the section was rewritten in 2002 to provide clarity for "industrial and multibuilding complexes and campus-style wiring". Why doesn't 90.2(A)(2) say all substations, or industrial and multibuilding complex substations, if that was the intent?

I believe what is really confusing about this issue is the following statement from the NEC Handbook (2005 edition):

Although such nonutility installations are within the scope of the NEC, the NEC requirements may not always be all-inclusive, for example, in clearances of conductors or in clearances from buildings or structures for nominal voltages over 600 volts. In such cases, the user can find additional information in the NESC ...

Basically, it says that the NEC applies to this equipment but the requirements for this equipment are not in the NEC.

I guess my real question is, what are the real requirements? When does the NEC take precedence and when does the NESC take precedence?

 

[jim dungar]

Will your substations be 'open air' or 'tamper resistant padmount' construction?
The NEC does not do a good job of >600 open air installations: these ususally require a lot of input from the AHJ. The NEC does okay with underground and enclosed equipment installations.

 

[rj_EE]

Mostly a lurker, but I'm interested in any other replies. I'm involved in a similar situation. A separate consultant is designing the MV loop, while I take over from the secondary on inside the building. The consultant designing the loop wants to size transformers per estimated demand load, however, I haven't found anything in NEC that allows it.

 

[Smart $]

... The consultant designing the loop wants to size transformers per estimated demand load, however, I haven't found anything in NEC that allows it.

For the most part, the NEC doesn't have any transformer sizing requirements. It only has requirements for protection of the transformer and conductors connected thereto.

 

[augie47]

It can get a bit tricky. Now your transformers are SDS systems and the conductors to your buildings are not services but transformer secondary conductors from a sDS so 240.4(B) does not apply.

(In the '11 Code 250.30(A)(2) also makes these installations interesting)