Thanks. It would be great if I could apply those exceptions, and use the existing cable.
It ends up that the new stove they bought is 13.9 KW.(convection oven)
When the ranges go over the 12KW, there is no demand factor for one that large?
I would have to wire this for the full 14000 watts, right?
Then 14000 divided by 240 equals 58 amps.
It will be a nice job, if they accept the estimate.
SJT
Using Table 220.55, you would increase the demand value in Column C by 5% for each KW over 12KW, so in your case that would equate to 10% or an extra 800W which would be 8800W making it 36.6A at 240V. That puts you within the ampacity of #8 NM.
Also, I agree that as long as you are not moving the location of the range, you can use the existing 3-wire setup with the new range.
