Help with SER cable ampacities

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nizak

Senior Member
I am looking to feed a 200 amp panel that is located about 115' from The meter base.

Here is the scenario.
- (1) 200 amp panel will be installed from the meter base at the point of entrance on the basement wall.

- A second 200 amp panel will be installed at the opposite end of the basement 115' away.It will be fed from a disconnect that is also located at the point of entrance on the basement wall.This panel will supply approx. 70% of the total load of the dwelling including hot tub and outbuilding.

PVC and single conductors aren't an option. (2" PVC thru I joists on 16" centers??)

SER cable makes the most sense.

Floor joist space will be un insulated.

Will I need to install 250 MCM to get my 200amp capacity?

Thanks
 
There are some variables such as the Code cycle involved and the load on the panel. Since the panel does not carry the full load of the residence the use of 310.15(B)(*) allowing a 4/0 AL or 2/0 Cu is not allowable. However, depending on the Code cycle,'you should still be able to use your 75° rating which is 180 amps for 4/0AL. If your load does not exceed 180 amps you can protect the cable with a 200 amp breaker.
 
Total load for this panel will be approx 150 A . The code cycle is 2014 we are working under.
 
If you are required to use 60C for the SER al conductor rating due to thermal insulation 4/0 = 150A -- 250 = 175A -- 300mcm = 200A -- If you can wait till 2017 code the restriction is going away for SER conductors larger than 10#
 
So for the 2014 cycle if I install without any insulation I can use the 75deg column?

Thanks.
 
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