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 Post subject: Service entrance
PostPosted: Tue Feb 09, 2021 7:01 pm 

Joined: Fri Jul 10, 2009 10:14 am
Posts: 30
Location: West Central, OH
We keeping debating what defines a service entrance per NEC. Take a typical large facility with multiple buildings . We purchase power and then it goes through our transformers, distributed across the facility and more transformers to lower the voltage again. Is the service enterance where we take ownership or the secondary of every transformer?


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 Post subject: Re: Service entrance
PostPosted: Wed Feb 10, 2021 3:16 pm 

Joined: Thu Apr 18, 2019 11:42 am
Posts: 41
willcoc wrote:
We keeping debating what defines a service entrance per NEC. Take a typical large facility with multiple buildings . We purchase power and then it goes through our transformers, distributed across the facility and more transformers to lower the voltage again. Is the service entrance where we take ownership or the secondary of every transformer?


IMHO, your service entrance is the feeders from your utility voltage transformation (e.g. 13.2kV to 480/277V or similar) to the main switchgear, switchboard, panelboard, etc. of each building.

If you are primary metered and have multiple large transformers for a campus system, then the demarcation point is called the "point of common coupling". This could be a metering cabinet owned by the utility, which then is the origination point of your campus electrical distribution system.

Mike

PS I'm sure there will be a few opinions on this.


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 Post subject: Re: Service entrance
PostPosted: Mon Feb 22, 2021 6:47 am 
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Joined: Thu Jan 10, 2008 8:49 pm
Posts: 500
Location: New England
I agree. The service begins where the utility feeders end. Stop and think, the utility is not obligated to follow NEC. But your distribution on your campus is.


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 Post subject: Re: Service entrance
PostPosted: Mon Feb 22, 2021 11:59 am 
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Joined: Sat Apr 04, 2009 9:50 pm
Posts: 114
Location: San Antonio, TX
So the first disconnecting means AFTER the POINT OF SERVICE is your SERVICE DISCONNECT. Main disconnects after the transformers fed by this SERVICE DISCONNECT are not SERVICE DISCONNECTS. Are you interested in identifying the SERVICE DISCONNECTS for grounding purpuses?


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 Post subject: Re: Service entrance
PostPosted: Mon Mar 01, 2021 8:05 am 

Joined: Mon Oct 19, 2009 7:42 am
Posts: 31
Services can be low voltage or high voltage (NEC definition) depending how you obtain your supply from the local utility. At our plant, we receive 115kV service and then transform and distribute within our customer owned distribution system. The NEC handbook has some good explanation of this distinction for campus styled multibuilding complexes in Art 90.2, 225.32, and 695.3 (C). The definition of service has changed over the years and many older engineers and electricians still use the old definitions. I have attached a few docs I developed to help explain services to my workforce. They may be of use to you also.


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