What is the minimum calculated service load for an 8 kW electric cooktop and 2-4 kW electric wall-mounted ovens installed in a dwelling unit if supplied by the same branch circuit?

To determine the minimum calculated service load for the appliances specified, one must consider the National Electrical Code (NEC) guidelines that apply to kitchen cooking appliances. When calculating the load, the electric cooktop and ovens can be combined, but there are specific rules about how to do this.

For an 8 kW electric cooktop, this load is fully accounted for in the calculation since this is a fixed input. For the wall-mounted ovens, when multiple ovens are installed (2 to 4 kW each), the NEC allows for a demand factor to reduce the total calculated load. Specifically, it states that you can take the highest-rated appliance at full load and then apply certain demand factors to the other appliances.

Typically, you would take the highest demand from the larger of the two ovens, which, if they both are rated the same, would still allow for the lower load to be considered somewhat reduced thanks to demand factors.

When you sum these loads together, the full load of the cooktop (8 kW) plus a typical demand allowance for the ovens, you would end up with a combined total of approximately 8.8 kW. Therefore, calculating the service load correctly using the prescribed NEC rules leads to determining that a minimum calculated