Mulitple Services to a building

[dcsva@aol.com]

We need to extend a 277/480vac/3ph/4w-200amp service and a 120/240vac/1ph-200amp service to the same building.

The 480 serves a water treatment equipment room and has a stand-by generator.
The 240 serves the rest of the building with no generator.

Does anyone have any suggestions and/or comments?
Where in the Code do I find info on this?

 

[bennie]

Re: Mulitple Services to a building

This appears to be design issue. Proper design procedure will assure meeting the code.

 

[don_resqcapt19]

Re: Mulitple Services to a building

230.2(D) would permit the two services, but in my area, the utility would not provide you with two services. They would supply you with one voltage, and you would have to install a transformer to get the second voltage.
Don

 

[dcsva@aol.com]

Re: Mulitple Services to a building

Don,
I will call Dominion Virginia Power tomorrow about that.

 

[dereckbc]

Re: Mulitple Services to a building

I agree with Don hear. If the utility will not supply two services, a transformer will do the trick. You would just need to arrange the transformer not to be fed from generator.

[ May 05, 2003, 09:59 PM: Message edited by: dereckbc ]

 

[frenchelectrican]

Re: Mulitple Services to a building

most power company in my area have a policy about using 2 diffrent services and they really discourage that practice now and if you have higher voltage (277/480v 3PH) and want use 120/240 volts single phase before they do that but now that is a specal service charge and they really dont want to do that any more to advoid probem and most comusters use the transfomer inside the building to down step to lower level as need and this is very common pratice to do that and my shop is the same way i have 277/480 volts for main power source then use the transfomer to down step to 120/240 volts single phase

merci marc

 

[goldstar]

Re: Mulitple Services to a building

The NEC does give you a guideline for this. Look at 230.1 A thru E. I had a similar situation last year where a bagel shop in a small strip mall required a 3 phase 120/240 service for their rotary oven and dough mixer. The other stores in the strip mall only had single phase services. I did have to install an ID plaque (230.1E) at the front of the building where the service attachment originated and over the meter at the rear of the building.

However, you'll have make some inquiries and do some research with your power company and the AHJ and plan this out beforehand. I wouldn't take this on without everyone in agreement.

 

[charlie]

Re: Mulitple Services to a building

The electric utility may be open to a second voltage for a price. Additionally, if you have an existing service that is at the maximum (ours is 3000 amperes), they may give you the second one at a different voltage.