What is the minimum feeder demand load for two 3 kW cooktops and two 5 kW wall-mounted ovens on separate branch circuits but on the same feeder?

What is the minimum feeder demand load for two 3 kW cooktops and two 5 kW wall-mounted ovens on separate branch circuits but on the same feeder?

• A. 9 kW
• B. 11 kW
• C. 15 kW
• D. 13 kW

Answer: (B)

The key idea is that when sizing a feeder for multiple cooking appliances, you don’t simply add every unit’s full rating. Demand factors account for the fact that these loads aren’t all at full use at the same time. For cooking appliances on the same feeder, you typically use the full rating for the smaller cooktop group and apply a reduced factor to the ovens group, recognizing that two wall ovens are unlikely to hit their full combined rating simultaneously. Compute the cooktops first: two units at 3 kW each gives 6 kW. For the ovens: two units at 5 kW each total 10 kW, but with a 50% demand factor applied to multiple cooking appliances on the same feeder, the ovens’ contribution becomes 10 kW × 0.5 = 5 kW. Add the two groups: 6 kW + 5 kW = 11 kW. So, the minimum feeder demand load is 11 kW.

The key idea is that when sizing a feeder for multiple cooking appliances, you don’t simply add every unit’s full rating. Demand factors account for the fact that these loads aren’t all at full use at the same time. For cooking appliances on the same feeder, you typically use the full rating for the smaller cooktop group and apply a reduced factor to the ovens group, recognizing that two wall ovens are unlikely to hit their full combined rating simultaneously.

Compute the cooktops first: two units at 3 kW each gives 6 kW.

For the ovens: two units at 5 kW each total 10 kW, but with a 50% demand factor applied to multiple cooking appliances on the same feeder, the ovens’ contribution becomes 10 kW × 0.5 = 5 kW.

Add the two groups: 6 kW + 5 kW = 11 kW.

So, the minimum feeder demand load is 11 kW.