This part of IEC 60317 specifies the requirements of enamelled rectangular aluminium winding wire of class 120 with a sole coating based on polyvinyl acetal 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 of application characteristics. The range of nominal conductor dimensions covered by this standard is Wires of grade 1 and grade 2 are included in this part of IEC 60317 and apply to the complete range of conductors. The specified combinations of width and thickness as well as the specific ratio width/thickness are given in IEC 60317-0-9.