310.15b6

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normbac

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Been asked to take over a project that was started about 6 mos. ago previous co. partially wired a house, home runs went to 3 locations.
There is a 400 amp ch panel about 270 ft. away from house on a framed back board. There is a 3 inch and two 1 1/2 conduits to house with pull box in between. Can I use 310.15 b6 to size one run in 3 inch 4/0 al to 200 amp and 1 runs in ea. 1 1/2 conduit to both 100 amp panels in home. Where the 1 1/2 conduits enter the dwelling(garage) can I bring them into a single pull box and continue with two seperate ser cables. also would I bond the ufer which is at the 200 amp in series to the 100 amp panels ? any corrections or better ideas appreciated. TIA
 
I believe the 2008 has made that clear that you cannot do what you are proposing. I think it was there in 2005 but others have argued it, hence the re-write
 
as Dennis says!
This was recently discussed here: http://forums.mikeholt.com/showthread.php?t=101885

Howver, I did a quick check in some tables and did not see a problem (conduit fill) with you using full size conductors per 310.16.. I may have missed something

My opinion would be that if you have the #4 from the 400 amp to your UFFER, you could tap off (split-bolt) to your 100 amp panels.
 
Thank you, Curt. You are correct, it would not comply.
I was too busy looking at the trees and missed the forrest.

(not knowing what Code is enforced at the OP's area AND only having an '08 in front of me, was that the case in '02 an '05 ? )
 
Yeah your right with 225.30
So any suggestions
The only thing I come up with is removing the 400 amp setting a meter and parallel up to the house to a 400 main lug panelboard then feed the 100 amp panelboards off the 400 Anything negative about that. :-? TIA
 
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