Maximum Distance from MDP for New MDP Section

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eeee

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It looks like the designer wants to add a new section to the MDP, but we have space limitations and would like to locate the new section some distance away and maybe even turning a 90 degree corner. It is expected that there will be a bus bar in rigid metal cylindrical conduit connecting the two MDP sections together.

NEC 550.11 or NEC 408 do not seem to give the maximum distance requirement between MDP sections (although I did seem to find some words about minimum distance separation) using a rigid metal cylindrical conduit bus bar or any other type of connection.

Can I make two sections of MDP separated by 3 feet and turning a 90 degree corner (connected together by a bus bar composed of power cable encased in rigid metal conduit)?
 

charlie b

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Location
Lockport, IL
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Retired Electrical Engineer
Re: Maximum Distance from MDP for New MDP Section

I think it would be acceptable. Will there be a breaker on MDP-1 to protect the conductors going to MDP-2?

By the way, I think you are going to confuse some readers with your use of the phrase "bus bar" to describe cables. That phrase is usually used to describe flat, wide, uninsulated metal bars of rectangular cross-section.
 

eeee

Senior Member
Re: Maximum Distance from MDP for New MDP Section

Just got a big surprise. The designer is now direct feeding all the subpanels and has found room in the one MDP to diect feed all the subpanels. Previously, he indicated that existing loads were occupying these breaker spaces on the MDP based on his MDP panel schedule.

It seems I better trace out all the loads in the building, since the designer probably does not know what is wired to what. I know that the existing drawings are not updated. The designer was responsible to make correct drawings regardless of the condition of the existing drawings.

I would hate to give this design to a construction contractor and see what impacts it would incur to our operation during construction.

Go figure I suppose on this one?
 
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