Single dwelling; Multiple "service"

[tmacdonald]

An industrial complex consisting of multiple buildings is serviced by a single 13.8V primary switch. The complex owner owns and maintains downstream distribution equipment. One of the buildings is adding 120K sq.ft. The existing building is fed from the a 750KVA transformer which feeds a 6 disconnect panel. The tenant is adding to add another 750KVA transformer to service addition. This transformer will be connected to a distribution panel with main overcurrent protection. This essentially means the building has 7 disconnecting means (6 in one location, the last about 400' away). Can they have 7 disconnects?

 

[charlie b]

Re: Single dwelling; Multiple "service"

I don?t see a problem with what you have described. I infer that the new transformer will have the same primary voltage as the existing transformer, and that it?s secondary will be separate from the secondary of the existing transformer (i.e., the two will not be operating in parallel).

There is no rule that says you can?t have more than 6 disconnects in a building. The rule is that you can?t have more than 6 disconnects on the secondary of any one transformer, unless there is a main disconnect ahead of the others. Once you have a main, you can have as many downstream disconnects as you like.

 

[tmacdonald]

Re: Single dwelling; Multiple "service"

Thank you for your response.

Your assumptions are correct. Both transformers are the same and no loads will use both transformers.

My understanding is the reason why a "building service" has a limited number of disconnects (all in the same location) is because the fire department would need to cut the power quickly in case of fire.

In the case where a complex having a primary service, does the fire company simply open the primary switch supplying all of the buildings?

 

[pierre]

Re: Single dwelling; Multiple "service"

230.71 Maximum Number of Disconnects.

Limits the number of disconnects to 6 for each service.

230..2 (B),(C)&(D) permit additional services as specified.

Pierre