Demand factor for appliance load in dwelling units is best described as which of the following?

Demand factor for appliance load in dwelling units is best described as which of the following?

• A. 75 percent for four or more appliances fastened in place
• B. 50 percent for four or more appliances fastened in place
• C. 100 percent for all appliances
• D. 25 percent for two or more appliances

Answer: (A)

Demand factor is the portion of the installed appliance load that you expect to draw power at the same time. In dwelling units, fixed appliances that are installed in place aren’t all used at full capacity together, so you apply a reduction to reflect likely simultaneous use. The standard practice for four or more fixed appliances is to take 75% of their total connected load as the appliance-demand load. This 75% accounts for the reality that several appliances may run together, but not at full rated power all at once. So, if the four or more fixed appliances have a combined full-load rating of, say, 8 kW, the appliance-demand load would be 0.75 × 8 kW = 6 kW. The other options imply too high or too low a simultaneous-load expectation for typical dwelling-unit appliance usage, making 75% the best choice among the given options.

Demand factor is the portion of the installed appliance load that you expect to draw power at the same time. In dwelling units, fixed appliances that are installed in place aren’t all used at full capacity together, so you apply a reduction to reflect likely simultaneous use. The standard practice for four or more fixed appliances is to take 75% of their total connected load as the appliance-demand load. This 75% accounts for the reality that several appliances may run together, but not at full rated power all at once.

So, if the four or more fixed appliances have a combined full-load rating of, say, 8 kW, the appliance-demand load would be 0.75 × 8 kW = 6 kW. The other options imply too high or too low a simultaneous-load expectation for typical dwelling-unit appliance usage, making 75% the best choice among the given options.