800A MCC Fed from Dual Source

M

mstoole1

Member
Location
Colorado
Occupation
Electrician
We have a situation where the utility company will be setting (2) 400A services that we must feed an 800A MCC from. The utility company states they are unable to set an 800A service.
Are we able to feed this 800A equipment from (2) 400A power sources? I'm thinking we are not, but can't find an NEC article stating this
 
charlie b

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
I believe you are right; this is not allowed by the NEC (I don't have my copy handy, so I can't cite the article). But where does the utility ownership end and the facility's responsibility begin? It might be allowed by their rules. That's as far as I can take it.
 
charlie b

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
I infer that the two 400 amp service disconnecting devices are downstream of the meters. That puts you into the NEC rules. I have a hard time believing the utility would suggest that installation.

Perhaps I am mis-remembering the NEC requirement (does "Charlie's Rule" apply here?). Can someone provide the code citation?
 
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