A kitchen has a cooktop rated 4 kW at 240 V and two ovens rated 5.5 kW at 240 V. What is the minimum load for this branch circuit in watts?

A kitchen has a cooktop rated 4 kW at 240 V and two ovens rated 5.5 kW at 240 V. What is the minimum load for this branch circuit in watts?

• A. 9,200
• B. 11,400
• C. 8,800
• D. 15,300

Answer: (A)

When sizing a branch circuit that serves multiple cooking appliances, you don’t simply add up every unit’s full rating. That’s because not all appliances run at full power at the same time. A demand factor is applied to reflect this diversity. For three or more cooking appliances, a factor around 0.61 is used to estimate the minimum load. Compute the total nameplate rating: 4 kW for the cooktop plus 5.5 kW and 5.5 kW for the two ovens gives 15 kW. Apply the demand factor: 15 kW × 0.61 ≈ 9.15 kW, which is about 9,150 W, typically rounded to 9,200 W. So the minimum load for this branch circuit is about 9,200 watts.

When sizing a branch circuit that serves multiple cooking appliances, you don’t simply add up every unit’s full rating. That’s because not all appliances run at full power at the same time. A demand factor is applied to reflect this diversity. For three or more cooking appliances, a factor around 0.61 is used to estimate the minimum load.

Compute the total nameplate rating: 4 kW for the cooktop plus 5.5 kW and 5.5 kW for the two ovens gives 15 kW. Apply the demand factor: 15 kW × 0.61 ≈ 9.15 kW, which is about 9,150 W, typically rounded to 9,200 W.

So the minimum load for this branch circuit is about 9,200 watts.