Calculator
Cable Area from Voltage Drop
Change the inputs to match your equipment. Results update automatically.
Formula
Three-phase: S = (sqrt(3) x I x L x rho) / (V x (e / 100))Single-phase: S = (2 x I x L x rho) / (V x (e / 100)) Worked example
For 32 A, 50 m, 400 V, ρ = 0.0175 Ω·mm²/m and a 3% drop allowance, the simplified three-phase result is about 4.04 mm². Select and verify a real cable separately.
Scope and interpretation
This is only a voltage-drop check. Ampacity, installation method, grouping, temperature and short-circuit withstand still require verification.