A 120/240-volt, single-phase feeder of a retail department store is to supply a noncontinuous load of 18,000 VA and a continuous load of 13,356 VA. What MINIMUM size 75 deg. C copper conductors are required for this installation?
1/0 AWG In compliance with Section 215.2(A)(1)(a), feeder conductors are to have an ampacity of 100% of the noncontinuous loads, plus 125% of the continuous loads. Therefore: 18,000 VA x 100% = 18,000 VA (noncontinuous load) 13,356 VA x 125% = 16,695 VA (continuous load) 34,695 VA total To find the load in amperes, apply the single-phase current formula: I = 34,695 VA = 144 amperes 240 volts As shown in Table 310.16, size 1/0 AWG conductors with an ampacity of 150 amperes should be selected.
