IEC 60317-27-4:2020 specifies the requirements of paper tape covered rectangular aluminium winding wires. This covering consists of two or more layers of paper tape and is primarily intended for winding coils for oil immersed transformers. The range of nominal conductor dimensions covered by this document is: – width: min. 2,00 mm max. 16,0 mm; – thickness: min. 0,80 mm max. 5,60 mm. The paper tapes included in this document are restricted to those specified in IEC 60554-1 and IEC 60554-3-5.