220.31(b)

[wmeek]

Is it saying you can take all existing and all new loads at nameplate VA and take 8000 at 100% and the rest of other loads at 40%, and then add all your A/C or Heating loads whichever is the larger load for both existing and new loads at 100% to derive your Main Service Size. I just am trying to make sure I have this right and am doing the correct calculation for adding loads to an existing dwelling.

Thanks

 

[dcspector]

Are you refering to 220.83?

 

[wmeek]

Yes 220.83(B) is the 2005 NEC
220.31(B) is in the 2002 Nec

 

[wmeek]

Is there anyone who has applied this section for seeing if an existing service is adequate to support a new add on.