I have a customer who is having their kitchen remodeled. They will be using a wall mounted oven, and a counter top range - two seperate appliances.
I'm not sure exactly which range the customer is buying, but I do know that four out of ten they are more than likely considering are above 8.75kW (9.6kW, 8.8kW, 9.6kW, 9.6kW).
The oven the customer is buying is a GE Profile JT955 - 7.2kW
The house is not currently wired for electrical cooking appliances in the kitchen. The panel only has room for one 2-pole breaker, however, I may be able to put in a quad. I'll have to look and check. If not, I want to use Table 220.19 and only use one circuit for both appliances. Actually, even if I could use a quad, I think 220.19 would be best for the customer (cheaper).
I'll do two calculations utilizing Table 220.19, one with an 8.75kW range, and one with a 9.6kW range.
7.2kW + 8.75kW = 15.95kW
15.95kW - 12kW = 3.95kW = 4kW
5% X 4kW = 20%
.20 X 8kW = 1.6kW
8kW + 1.6kW = 9.6kW
9.6kW / 240V = 40A
Are my formulas correct? If so, according to Table 220.19, I can use a single 50A circuit to supply both appliances.
Table 310.16 says 8-3 SE cable (75 degrees C) or 6-3 NM cable (60 degrees C - Article 334.80) would work for a 50A circuit.
12kW (because 9.6kW is over 8.75kW) + 7.2kW = 19.2kW
19.2kW - 12kW = 7.2kW
5% X 7.2kW = 36%
.36 X 8kW = 2.88kW
2.88kW + 8kW = 10.88kW = 10.9kW
10.9kW / 240V = 45.41A
Can I use a 50A circuit, or do I need to go to a 60A circuit. 45.41A is 91% of a 50A circuit. If a 60A, then I need to use 6-3 SE cable or 4-3 NM cable.
Can I even use a 60A circuit for appliances? Look at Article 422.10(B). This refers you to Article 210.23. Article 210.23(D) is what scares me.
I know that according to the last sentence of Article 422.10(A) that you can use Table 220.19 if you'd like, but it seems that Article 220.19 and Article 422.11(A) contradict each other.
Anyway, could you please look this over and tell me I'm fine? I don't mind doing a panel upgrade if necessary, but if I can help out the customer and save them some time and money, I'd like to.