cogen service

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mcelweec@gmail.com

CMAC1
Location
NYC
Occupation
Electrician
i have a situation where i have two services.one service 208/120v poco service,the other 480v 3 wire from cogen plant.the 208 service has been upgraded from 400a to 800a,the 480v 3 wire service has been slightly modified.this is a stand alone building in a residential/commercial complex.how do i legally bond the 480v system? the code is 2005 nec with 2007 nec amendments.
 
So I assume they are not independent.
There must be some kind of transfer switch involved.
If both were independently grounded and bonded then the transfer switch would have to break the grounded conductor as well as the ungrounded conductor.
 
mcelweec@gmail.com said:
two completely separate services operating 24/7 independent of each other.
Click to expand...

If that's the case why could you not ground and bond Each of these separately?

I take it the grounded conductors do not inter mix, and are not connected in any way?

If they did you could not bond the non-utility portion.
I just went back and read your first post, you have a three wire delta 480.
 
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On a 3phase delta you can corner ground the the service, or you may be able to put in ground detectors 250.21 A and B.
Make sure you read 250.21 (A)(3)

250.20 FPN
 
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my readings are 277v to ground from each phase and 480v phase to phase.i am unfamiliar with corner ground delta systems ,but this seems to be a wye system,educate me please.
 
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