Use our free kW to Cable Size Calculator to find the correct wire size. Enter kW, voltage, and length for IEC-compliant copper or aluminum cable results. Our calculator ensures safety, prevents overheating, and accounts for voltage drops and derating factors according to IEC standards. Terms and Conditions Cable size is selected by checking both adjusted ampacity and voltage drop. Input your electrical parameters to get accurate wire size. In this complete guide, we'll walk you through the complete cable sizing process based on IEC 60364-5-52 standards.