Using the optional calculation method, less than four separately-controlled electric space-heating units are calculated at what percent of their nameplate ratings?

Using the optional calculation method, less than four separately-controlled electric space-heating units are calculated at what percent of their nameplate ratings?

• A. 100%
• B. 40%
• C. 125%
• D. 65%

Answer: (D)

In the optional calculation method for electric space heating, you adjust the load based on how many heating units you have, recognizing that not all of them will run at full power at the same time. When there are fewer than four separately controlled space-heating units, you take 65% of each unit’s nameplate rating and sum those to get the calculated load. If you have four or more units, you use 100% of the nameplate ratings. This approach helps avoid overestimating the demand with a small number of heaters. For example, three heaters rated at 6 kW each would yield 3 × 6 × 0.65 = 11.7 kW under the optional method.

In the optional calculation method for electric space heating, you adjust the load based on how many heating units you have, recognizing that not all of them will run at full power at the same time. When there are fewer than four separately controlled space-heating units, you take 65% of each unit’s nameplate rating and sum those to get the calculated load. If you have four or more units, you use 100% of the nameplate ratings. This approach helps avoid overestimating the demand with a small number of heaters. For example, three heaters rated at 6 kW each would yield 3 × 6 × 0.65 = 11.7 kW under the optional method.