Definition of "utility" as it pertains to a campus distribution system

Status
Not open for further replies.
bbaumer

bbaumer

Senior Member
Location
Indiana
Try to make this as simple a question as possible.

A large university campus takes delivery of power from the area power company at 34kV or higher or whatever. Doesn't matter.

The university owns their own substation and transformers to step down to 12470V and distributes at this voltage underground to all campus buildings over several hundred acre area and 60+ buildings.

A pad mount transformer is set at the each building to step down to 480Y/277V or 208Y/120V which in turn feeds an MDP in the building with main disconnect.

Question. Are these pad mounts and MDP's services or are they separately derived systems? i.e. can the University be considered the utility or not? This makes a big difference in grounding and bonding and if the 240.21 tap rules are applied or not.

Please justify your answer with backup codes, laws etc.

Thanks.
bbaumer
 
Have the same situation here.
I spoke with Mike Holt himself on this topic last year at a grounding & bonding seminar.

Article 100 - Definition of Service.
"The conductors and equipment for delivering electric energy FROM THE SERVING UTILITY to the wiring system of the premises served."

There is no NEC definition of 'Utility'.

Yes, they are ELECTRICALLY identical, but the campus distribution can not be considered 'service'.

db
 
barclayd said:
Have the same situation here.
I spoke with Mike Holt himself on this topic last year at a grounding & bonding seminar.

Article 100 - Definition of Service.
"The conductors and equipment for delivering electric energy FROM THE SERVING UTILITY to the wiring system of the premises served."

There is no NEC definition of 'Utility'.

Yes, they are ELECTRICALLY identical, but the campus distribution can not be considered 'service'.

db
Click to expand...

Makes it no more clear, to me anyway. REMC does not generate any power. They buy it from another company. They own the substations and distribution, yet REMC is the utility.

Big State University does not generate any power. They buy it from another company. They own the substations and distribution, yet are they the utility? A PRIVATE utility?

That's why I am after the definition of "utility". If Big State U can be considered the serving utility or not.....

Thanks for the reply.
 
There's a thing here called the Public Utilities Commission.
It might all have something to do with Revenue.

Although, we have metering on all our buildings, and the various departments are 'charged' for electricity.

Don't know - like you say, it makes a difference in how you wire stuff.

Where's MIKE HOLT when you really need him? Probably getting a foot massage somewhere in the South Pacific.

db
 
Everything entering a building downstream of the utility's point of service, namely the substation, is a "feeder," not a "service." Code reference: Article 100. :wink:
 
In my opinion the university is not an utility and their conductors are feeders, not service conductors and their transformers are SDS. The rules in the NEC apply to this installation. the scope statement that says the NEC does not apply to electric utilities, is intended to exempt only publicly regulated utilities and not campus or industrical installations that have distribution or even generation systems very much the same as an electric utility would.

As far as the code goes, if you are on the 2005 code and use non-metallic raceways between the pad mount transformer and the building, there is no real difference between a NEC installation and a utility installation in the grounding and bonding of the installation. 240.21(C)(4) gives some relief on the transformer secondary conductors, but does limit you to a single main OCPD at the building.

There is a task group working on a new code article for the 2011 code to help address these types of installations.
 
don_resqcapt19 said:
In my opinion the university is not an utility and their conductors are feeders, not service conductors and their transformers are SDS. The rules in the NEC apply to this installation. the scope statement that says the NEC does not apply to electric utilities, is intended to exempt only publicly regulated utilities and not campus or industrical installations that have distribution or even generation systems very much the same as an electric utility would.

As far as the code goes, if you are on the 2005 code and use non-metallic raceways between the pad mount transformer and the building, there is no real difference between a NEC installation and a utility installation in the grounding and bonding of the installation. 240.21(C)(4) gives some relief on the transformer secondary conductors, but does limit you to a single main OCPD at the building.

There is a task group working on a new code article for the 2011 code to help address these types of installations.
Click to expand...

The difference as I see it is:

Service: having the copper braided strap from Xo at the transformer AND the main bonding jumper installed in MDP and no EGC from the xfmer to MDP, using the grounded conductor as the EGC per 250.142(A)(1)

SDS: Either no main bonding jumper in MDP or no strap from Xo to xfmr case and EGC run from xfmer to MDP, plus tap rule limitations of 240.21(C) depending on case.

Easier and cheaper to be considered a service, and dare I say, just as safe???
 
bbaumer said:
The difference as I see it is:
Click to expand...
Don't forget that the protective device selection and operation (both L-L and L-G) for utilities is different than for customers, and utilities have different grounding schemes (i.e. MGN). These are also part of the reason that articles 230 and 240 have different requirements.
 
bbaumer said:
The difference as I see it is:

Service: having the copper braided strap from Xo at the transformer AND the main bonding jumper installed in MDP and no EGC from the xfmer to MDP, using the grounded conductor as the EGC per 250.142(A)(1)

SDS: Either no main bonding jumper in MDP or no strap from Xo to xfmr case and EGC run from xfmer to MDP, plus tap rule limitations of 240.21(C) depending on case.

Easier and cheaper to be considered a service, and dare I say, just as safe???
Click to expand...
I was not really looking at it as a SDS, but as two structures and under the 2005 code bonding at both structures was permitted in some cases. I think you can argue this one both ways. Under the 2008 code there is no question that you would need both a grounding and a grounded conductor between the transformer and the building.

The major tap rule issue is the fact that the tap rule requires that the conductors terminate in a single OCPD where the service is not required to do that.
 
From 90.2(B)(5)

FPN to (4) and (5): Examples of utilities may include those entities that are typically designated or recognized by governmental law or regulation by public service/utility commissions and that install, operate, and maintain electric supply (such as generation, transmission, or distribution systems) or communication systems (such as telephone, CATV, Internet, satellite, or data services). Utilities may be subject to compliance with codes and standards covering their regulated activities as adopted under governmental law or regulation. Additional information can be found through consultation with the appropriate governmental bodies, such as state regulatory commissions, the Federal Energy Regulatory Commission, and the Federal Communications Commission.

In other words, an electric utility an electric utility because the federal and/or your state government says it is. :)
 
don_resqcapt19 said:
...
The major tap rule issue is the fact that the tap rule requires that the conductors terminate in a single OCPD where the service is not required to do that.
Click to expand...

That not what the tap rule is about... I'd Question your statement up to the OCPD
 
Here's an excerpt from someone elses opinion on this I got via email:

"Each of your campus buildings that are separately served from the primary system, should be considered a ?service point?. Big State U acts as a ?utility?. In practice, you meter and treat each building as a separate service, even if you don?t send invoices. Just like it would be if each of your buildings was a separate customer in a commercial park. Only your trained and qualified personnel have access to, operate, and maintain the outdoor system. The National Electrical Safety Code, which applies to the outdoor circuits of utilities and similar systems on commercial and industrial premises, helps with this:

NESC, Section 1, 011. Scope, Paragraph A
These rules cover supply and communication lines, equipment, and associated work practices employed by a public or private electric supply, communications, railway, or similar utility in the exercise of its function as a utility. They cover similar systems under the control of qualified persons, such as those associated with an industrial complex or utility interactive system.


If for some reason further authority is required, you could talk to a state inspector and ask them as per NEC:

NEC, Article 90, 90.2 Scope, Section (C) Special Permission
The authority having jurisdiction for enforcing this Code may grant exception for the installation of conductors and equipment that are not under the exclusive control of the electric utilities and are used to connect the electric utility supply system to the service-entrance conductors of the premises served, provided such installations are outside a building or terminate immediately inside a building wall."

Just some more food for thought on this........
 
cadpoint said:
That not what the tap rule is about... I'd Question your statement up to the OCPD
Click to expand...
Take a look at 240.21(C)(4). This would be a comparable installation as when the utility runs service conductors from their transformer to your building. The only real difference is that if the utility installs the conductors you can have multiple OCPDs and if you install them you are limited to a single OCPD.
 
It was just the your phrasing ...

I'm going to go with the previous statement say about "Big U" on this one..

I've seen some service laterals, and thier comissoning of thier own work.
A service point is established and work is NEC downline, I don't mean to miss state that.

All work is done today with an OCPD! The exact statement of a disconnect infront of a lateral is modern day practice, Yes.

And yes, many people will never see a lateral service with-out a disconnect as (as I beleive missing) in the OP.

But

If a dedicated, declared service (latereral or other) is installed and maintained buy the POCO, or a Utility Service there of, well, Who's is it ?
The odd install under "their control" do exist, and hopefully are not grandfathered, but do exist, and still installed.

Down-line, yes it should be US and the NEC, never a question.

Breaker / disconnect the circuit...
 
Last edited:
bbaumer said:
This makes a big difference in grounding and bonding and if the 240.21 tap rules are applied or not.

Please justify your answer with backup codes, laws etc.

Thanks.
bbaumer
Click to expand...

As far as grounding issues go, SDS transformers are very simular to
service transformers. In "most" underground distribution to campus style buildings, exception # 2 in 250.30(A)1 can be applied.
Rick
 
RUWired said:
As far as grounding issues go, SDS transformers are very simular to
service transformers. In "most" underground distribution to campus style buildings, exception # 2 in 250.30(A)1 can be applied.
Rick
Click to expand...

I totally missed that. I think we have a winner with this exception.

Thanks!
 
Correct me if I'm wrong but,

Doesn't the "utility" side of things use one ground (multigrounded neutral system) and the "customer" use a neutral and safety ground? How would the NEC (or relevant code) play into what you can and cannot do for grounding in these types of systems where you must deal with both high voltages and customer distribution voltages given the campus owns both the high voltage and the low voltage system?
 
Last edited:
Status
Not open for further replies.
Top