When a branch circuit feeds both noncontinuous and continuous loads, the circuit must be sized to accommodate 100% of the noncontinuous load plus what percent of the continuous load?

• A. 115%
• B. 125%
• C. 110%
• D. 120%

Answer: (B)

When sizing a branch circuit that feeds both continuous and noncontinuous loads, you must treat continuous loads as needing a 125% allowance. Continuous loads are those that run for three hours or more, which causes more heating in conductors and equipment. Noncontinuous loads don’t run long enough to cause that sustained heating, so they’re counted at 100%.

Therefore, you sum 100% of the noncontinuous loads plus 125% of the continuous loads to determine the required circuit capacity. This is why the percent used for the continuous portion is 125%.

For example, if noncontinuous loads total 8 A and continuous loads total 6 A, the required circuit capacity would be 8 + (1.25 × 6) = 15.5 A, so you’d size the circuit to at least 20 A.