480V three-phase systems are the backbone of commercial and industrial electrical distribution. Motor feeders, distribution panels, and equipment branch circuits at 480V benefit from the reduced current compared to 240V for the same kW load — which generally means smaller wire and less voltage drop. However, long runs in large facilities, outdoor switchgear feeds, or motor circuits at the far end of a distribution board can still produce significant voltage drop. NEC 210.19(A) and 215.2(A) recommend no more than 3% for branch circuits and 2% for feeders, with a combined maximum of 5%. This calculator uses the three-phase voltage drop formula with the correct 1.732 factor.
For a 480V 3-phase 50A motor feeder at 400 ft using 6 AWG copper: VD = 1.732 × 12.9 × 50 × 400 / 26,240 ≈ 17.0V (3.55%). Exceeds 2% feeder recommendation — upsize to 3 AWG for VD ≈ 1.9%.
This is a variant of the full Voltage Drop Calculator — which supports all phases, wire materials, and distances in a single tool.
Try all options in the full Voltage Drop Calculator →