Calculate the voltage drop for a 100A, 3-phase feeder with 150 feet of 2 AWG copper conductors.

Using the formula Vd = (sqrt(3) x I x L x R)/1000 for 3-phase, where R is resistance per 1000 ft. For 2 AWG copper at 75C, R = 0.194 ohms/1000ft. Vd = (1.732 x 100 x 150 x 0.194)/1000 = 5.04V. For 480V system, this is 1.05% drop; for 208V system, this is 2.4% drop. The calculation helps verify conductor sizing meets the 3% branch/5% total voltage drop recommendations.