Large Commercial Building Service Sizes

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Electriman

Senior Member
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TX
Greetings,

I was wondering if we have standard sizes of electrical service for large commercial buildings. The buildings that use more than 2000 A at 480 VAC three phase i.e. do we have 3500 A service?

Thank you in advance.
 
Electriman said:
Greetings,

I was wondering if we have standard sizes of electrical service for large commercial buildings. The buildings that use more than 2000 A at 480 VAC three phase i.e. do we have 3500 A service?

Thank you in advance.
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There are no 3500 ampere services that I am aware of. 3500 amps is not a standard size overcurrent device per 240.6. 3000 is the largest service I have seen around here. The POCO can also limit the size of the services that they offer.
 
We typically install 4000 amp services. Since they often do not have a single main they may not be required to be a standard size in 240.6.
 
infinity said:
We typically install 4000 amp services. Since they often do not have a single main they may not be required to be a standard size in 240.6.
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I have seen 3000A and 4000A but nothing in between. Is there anything in between? What do we have to do if the service is larger?
 
If you need larger, depending on where you are, they may go as large as 5000A or 6000A, but most often they will push you to a medium voltage service.

Sometimes the utility will just provide multiple smaller services.

Also sometimes, you will think you need a very large service per NEC 220, and the utility will laugh and provide you with a tiny service and connect a few sets of paralleled conductors to your many many sets of paralleled sets.
 
ron said:
If you need larger, depending on where you are, they may go as large as 5000A or 6000A, but most often they will push you to a medium voltage service.

Sometimes the utility will just provide multiple smaller services.

Also sometimes, you will think you need a very large service per NEC 220, and the utility will laugh and provide you with a tiny service and connect a few sets of paralleled conductors to your many many sets of paralleled sets.
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Normally, utilities service transformer is only a third of what my load analysis says. Apparently, NESC allows them to do that.
 
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