IEC/TS 60815-2:2008(E) is applicable to the selection of ceramic and glass insulators for a.c. systems, and the determination of their relevant dimensions, to be used in high-voltage systems with respect to pollution. This part of IEC 60815 gives specific guidelines and principles to arrive at an informed judgement on the probable behaviour of a given insulator in certain pollution environments. This first edition of IEC/TS 60815-2, together with IEC/TS 60815-1, cancels and replaces IEC/TR 60815, which was issued as a technical report in 1986.