SECOND SERVICE/EMERGENCY

[sleepy]

THE CODE SAYES YOU CAN HAVE A SECOND SERVICE FOR
EMERGENCY INTO A BUILDING. OK, I HAVE A EXISTING BUILDING, WITH A 600AMP SERVICE. I ALSO HAVE A EXISTING 600A GENERATOR. I HAVE BETWEEN 900 AND 1000AMPS, FOR THE NEW SPACE, DEMAND LOADS. THE NEW SPACE WILL BECOME A BANK, WE HAVE COMPUTOR SPACES AND OTHERS LOADS WE WANT ON EMERGENCY. INSTEAD OF UPGRADING THE 600 TO 1000 OR 1200 WE WANT TO BRING IN A SECOND SERVICE. A EMERGENCY LINE. I KNOW THE SECOND SERVICE THE OWNER PAYES FOR IT ALL. THE SECOND SERVICE COMES INTO A TRANSFER SWITCH. THE POWER COMPANY TELLS ME THAT THIS EMERGENCY LINE IS OFF LINE UNTIL THE POWER TO THE BUILDING FAILS. HOW DOES IT KNOW, AND DOES THIS SOUND CORRECT. THANK YOU

 

[rich000]

Re: SECOND SERVICE/EMERGENCY

Unless the second utility feed comes from another part of the power grid, on a loss of power, you will lose both feeds.

I am not sure of your setup, but wouldn't it be more cost feasible if you just ran all the feeds you wish to back up to a new panel and then feed that panel from the existing utility and the generator via an ATS?

 

[jerryb]

Re: SECOND SERVICE/EMERGENCY

Too many questions and comments start running thru my mind.

First, you can't run an electrical service directly to a transfer switch unless the switch is "service entrance" rated which is not the normal transfer switch construction. Second, NEC does not allow more than one service, but that would be in different locations within the building. You could bring in a separate service lateral into the same location as the first service and create two 600 amp service mains. Then this new service could run thru a transfer switch and then to a distribution panel for the desired loads.

 

[drmoody]

Re: SECOND SERVICE/EMERGENCY

It sounds to me like the correct answer is to upgrade the service to 1200A and keep the generator for emergency power. Put all your emergency circuits into a panel that will also be fed from the transfer switch. I hope you didn?t bid the job. Upgrading the service could get expensive. True, 230.2(A) and 700.12(D) say a separate service can be used for an emergency source, but it sounds like you will be drawing continuous current from this source to make up for your lacking 600A primary service. You might be able to get written permission from the AHJ and use 230.2(B)(2) as your reason for two services. Review 230.2.

Brian