IEC 60811-301:2012 gives the procedure to determine the permittivity at 23 °C which typically applies to filling compounds used for optical cables, communication cables and optical fibre cables. IEC 60811-301:2012 cancels and replaces Clause 9 of IEC 60811-5-1:1990, which is withdrawn. Full details of the replacements are shown in Annex A of IEC 60811-100:2012. There are no specific technical changes with respect to the previous edition, but see the Foreword to IEC 60811-100:2012. This publication is to be read in conjunction with IEC 60811-100:2012.