This part of IEC 60317 specifies the requirements of solderable enamelled round copper winding wire of class 180 with a sole coating based on polyurethane resin, which may be modified providing it retains the chemical identity of the original resin and meets all specified wire requirements. NOTE A modified resin is a resin that has undergone a chemical change, or contains one or more additives to enhance certain performance or application characteristics. The range of nominal conductor diameters covered by this standard is as follows: – Grade 1: 0,018 mm up to and including 1,000 mm; – Grade 2: 0,020 mm up to and including 1,000 mm. The nominal conductor diameters are specified in Clause 4 of IEC 60317-0-1:2013.