Each apartment in a 50-unit apartment complex has a 1.6 kW dishwasher. Using the optional method, determine the demand in kW on the service for these dishwashers.

• A. 20 kW
• B. 20.8 kW
• C. 26.4 kW
• D. 80 kW

Answer: (B)

The concept being tested is using the optional method to determine demand by applying a demand factor to fixed appliance loads, reflecting that not all appliances run at full power at the same time.

For these dishwashers, first find the total connected load: 50 units × 1.6 kW each = 80 kW. Then apply the appropriate demand factor from the optional-method appliance data for fifty dishwashers, which is 0.26. Multiply: 80 kW × 0.26 = 20.8 kW. So the demand on the service is 20.8 kW.

The full load would be 80 kW if every dishwasher ran at once, and using a factor like 0.25 or 0.33 would give 20 kW or 26.4 kW respectively, but the standard factor for this scenario yields 20.8 kW, which is why that result is correct.