This part of IEC 60317 specifies general requirements of glass-fibre braided resin or varnish impregnated, bare or enamelled rectangular copper wire. The range of nominal conductor dimensions is given in the relevant specification sheet. When reference is made to a winding wire according to IEC 60317-39 or IEC 60317-40 mentioned under Clause 2, the following information is given in the description: – reference to IEC specification; – nominal conductor dimensions in millimetres (width × thickness); – grade of coating and glass covering. The coating shall be characterised by the following grades of thickness: - BGL1, bare conductor with 1 braided layer of glass fibre - BGL2, bare conductor with 2 braided layers of glass fibre - grade 1 BGL1, enamelled grade 1 (grade 1) with 1 braided layer of glass fibre (BGL1) - grade 1 BGL2, enamelled grade 1 (grade 1) with 2 braided layers of glass fibre (BGL2) - grade 2 BGL1, enamelled grade 2 (grade 2) with 1 braided layer of glass fibre (BGL1) - grade 2 BGL2, enamelled grade 2 (grade 2) with 2 braided layers of glass fibre (BGL2)