Defines 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 degree C. The temperature in degrees Celsius corresponding to the temperature index is not necessarily that at which it is recommended that the wire be operated and this will depend on many factors, including the type of equipment involved.