Which statement best describes the optional method's approach to dwelling unit loads?

Which statement best describes the optional method's approach to dwelling unit loads?

• A. It uses fixed percentages for all loads.
• B. It applies demand factors to space heating, small appliance, and other loads.
• C. It ignores lighting loads.
• D. It requires 100% of nameplate ratings for all loads.

Answer: (B)

The optional method is about using demand factors to reflect that dwelling unit loads don’t all peak at once. Instead of sizing every device at 100% of its nameplate, this method lowers the calculated load by applying demand factors to chosen categories. For dwelling units, those categories include space heating, the small-appliance loads (the kitchen and general receptacles), and other general loads. By applying these factors, you get a more realistic peak load and can size conductors and overcurrent protection accordingly. This approach is optional and helps avoid over-sizing. The other options miss the point: fixed percentages for all loads, ignoring lighting, or demanding 100% of nameplate ratings all contradict how the optional method treats load diversity.

The optional method is about using demand factors to reflect that dwelling unit loads don’t all peak at once. Instead of sizing every device at 100% of its nameplate, this method lowers the calculated load by applying demand factors to chosen categories. For dwelling units, those categories include space heating, the small-appliance loads (the kitchen and general receptacles), and other general loads. By applying these factors, you get a more realistic peak load and can size conductors and overcurrent protection accordingly. This approach is optional and helps avoid over-sizing. The other options miss the point: fixed percentages for all loads, ignoring lighting, or demanding 100% of nameplate ratings all contradict how the optional method treats load diversity.