IEC 60317-70-2:2020 specifies the requirements of polyester glass-fibre wound resin/varnish impregnated bare, grade 1 or grade 2 enamelled round copper winding wires, temperature index 155. The impregnating agent can be, for instance, epoxy, polyester, or polyesterimide resin based. The nominal conductor diameters are specified in Clause 4 of IEC 60317-0-10:2017. NOTE For this type of wire, the heat shock test is inappropriate and therefore a heat shock temperature cannot be established. Consequently, a class based on the requirements for temperature index and heat shock temperature cannot be specified.