Muhammad S. answered • 08/19/23
PhD in Electrical Engineering with 10+ Years of Teaching Experience
To determine the minimum conductor size for the given loads on a single-phase, 240/120-volt feeder according to NEC Article 220, consider the continuous and noncontinuous loads separately and apply the appropriate demand factors. The NEC provides guidelines for calculating conductor sizes based on load characteristics. The continuous load is calculated at 125% of the continuous current. The noncontinuous load is calculated at 100% of the noncontinuous current. The total load is sum of the two. To determine the minimum conductor size, use the calculated total load and refer to the NEC Table 310.15(B)(16) for ampacity ratings of conductors. The minimum conductor size will be based on the ampacity that can safely carry the total load in Amperes. Also consider factors such as the insulation type, temperature rating, and other installation conditions to select the appropriate conductor from the table.
