How do I calculate voltage drop for a long run?
Use Vd = 2 × K × I × D / CM for single-phase (×√3 for three-phase), where K is conductor resistivity (12.9 copper / 21.2 aluminum), I is load current in amps, D is one-way distance in feet, and CM is conductor circular mils. Increase wire size whenever the result exceeds 3% on a branch circuit.
Answers
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