Service entrance - and buildings served

[Isaiah]

This plant has a 230kV outdoor utility substation which is privately owned, ie not part of the city’s power distribution. The utilization power is 13.8kV which runs to switchgear in 5 different buildings on site and then downstream to transformers which feed more buildings at 480V.
If the incoming 230kV is considered the premise Service Entrance, is each transformer/switchgear downstream considered a separate Service, Sub-service or a separately derived system?


Sent from my iPhone using Tapatalk

 

[augie47]

A SDS ....

Service Point. The point of connection between the facilities of the serving utility and the premises wiring

 

[Isaiah]

A SDS ....

Service Point. The point of connection between the facilities of the serving utility and the premises wiring

Thanks Augie. Does each building downstream constitute a Service?


Sent from my iPhone using Tapatalk

 

[augie47]

Thanks Augie. Does each building downstream constitute a Service?


Sent from my iPhone using Tapatalk

No, as noted, the service point is where the utility connects.
Everything else is SDS & transformer secondary conductors. In many respect the wiring will resemble services such as requiring grounding electrodes, etc. but by definition the service stopped at the 230kv point.

 

[Isaiah]

No, as noted, the service point is where the utility connects.
Everything else is SDS & transformer secondary conductors. In many respect the wiring will resemble services such as requiring grounding electrodes, etc. but by definition the service stopped at the 230kv point.

Great, that’s what I needed to know.


Sent from my iPhone using Tapatalk

 

[Isaiah]

No, as noted, the service point is where the utility connects.
Everything else is SDS & transformer secondary conductors. In many respect the wiring will resemble services such as requiring grounding electrodes, etc. but by definition the service stopped at the 230kv point.

Augie, If the 230kV substation is located on the owners property does the NEC apply? The NEC is referenced in the owner specification


Sent from my iPhone using Tapatalk

 

[augie47]

I've seen a lot of different situations between POCO and customers as to ownership & responsibility. Sometimes the equipment is purchased. sometimes leased from POCO, etc. There should be an understanding as to where the "service point" is located and anything beyond that would be NEC. The answer may be in the hands of the legal eagles.

 

[don_resqcapt19]

Augie, If the 230kV substation is located on the owners property does the NEC apply? The NEC is referenced in the owner specification


Sent from my iPhone using Tapatalk

While the NEC does a very poor job with high voltage systems, it applies if the high voltage system is on the load side of the service point. The ownership of the property does not make a difference, as often utility substations are located on the owners property.

Most of the time, the AHJ will default to the engineering design of the high voltage system, and will often hire a person experienced in high voltage installations to do the inspection.

 

[Isaiah]

While the NEC does a very poor job with high voltage systems, it applies if the high voltage system is on the load side of the service point. The ownership of the property does not make a difference, as often utility substations are located on the owners property.

Most of the time, the AHJ will default to the engineering design of the high voltage system, and will often hire a person experienced in high voltage installations to do the inspection.

Confused here…how can the high voltage be on the load side of the service point? Isn’t the service point where the load side goes downstream to the facility?


Sent from my iPhone using Tapatalk

 

[don_resqcapt19]

Confused here…how can the high voltage be on the load side of the service point? Isn’t the service point where the load side goes downstream to the facility?


Sent from my iPhone using Tapatalk

Your original post says the 230 kV substation is customer owned, putting the service point on the primary side of the 230 kV substation. The service point will be the line side of the primary OCPD for the 230kV to 13.8kV transformer.

 

[Isaiah]

Your original post says the 230 kV substation is customer owned, putting the service point on the primary side of the 230 kV substation. The service point will be the line side of the primary OCPD for the 230kV to 13.8kV transformer.

Got it - thanks for clarification. If the entire substation yard were considered under NEC, how would grounding be inspected since this is usually installed per IEEE-80, not Art 250?


Sent from my iPhone using Tapatalk

 

[jim dungar]

Got it - thanks for clarification. If the entire substation yard were considered under NEC, how would grounding be inspected since this is usually installed per IEEE-80, not Art 250?


Sent from my iPhone using Tapatalk

The NEC is a minimum standard. It is quite common to find standards like those from IEEE and the NESC to also be employed on customer owned HV and MV substations. Ground inspection is often done by a third party who issues a certified report, which an AHJ accepts.