Sizing of conductor and circuit protection device?

[KSue]

I have a cooktop 7.7kw, (40A, 240V)and two ovens 3.6kw each (20A, 240V). I want to put them on one circuit. How do I use the NEC 220.55 table to size them as one appliance? This is for 120/240 service. The total demand rating is more than 12kw, and I don't know how columns A&B relate to column C in the table.

What is the process for calculating the breaker and the conductor at the junction box?

 

[charlie b]

Is this an exercise for one of your classes, or are you talking about something you are really installing in your own home? If it is a class assignment, then we would appreciate seeing you make an attempt, tell us what answer you got and how you got it, so that we can then help you take the next step. If this is a do-it-yourself project for your own home, and if you are not licensed to do this type of work, then forum rules might not allow us to help you. I say "might not," because we can only provide how-to assistance to a person who is employed in the industry, or to a person who is seeking employment in the industry and who is undertaking the project as part of a work-related assignment. Your current status is not clear to me, based on what you put into your profile. Could you please explain the nature of this question?

 

[charlie b]

I have removed all responses to this thread, and am now closing it, in accordance with the Forum?s rules. This Forum is intended to assist professional electricians, inspectors, engineers, and other members of the electrical industry in the performance of their job-related tasks. However, if you are not an electrician or an electrical contractor, then we are not permitted to help you perform your own electrical installation work.