This International Standard specifies the requirements of enamelled round copper winding wire of class 220 with a sole coating based on polyimide resin. Class 220 is a thermal class that requires a minimum temperature index of 220 and a heat shock temperature of at least 240 °C. The range of nominal conductor diameters covered by this standard is: - Grade 1: 0,020 mm up to and including 2,000 mm; - Grade 2: 0,020 mm up to and including 5,000 mm.