IEC 60230:2018 defines the procedure for carrying out withstand lightning and switching impulse tests and withstand superimposed impulse test on cables and their accessories. This document applies solely to the methods of carrying out the tests as such, independently of the problem of selecting the test levels to be specified. The voltages pertaining to the system on which cables and accessories are to be used are given in IEC 60183 or in the relevant product standard. This document specifies the following requirements: - the characteristics and state of the test installation and those parts of the procedure which are common to withstand tests and tests above the withstand level; - the procedure for carrying out withstand lightning, switching impulse tests and superimposed impulse test; - the procedure for carrying out tests above the withstand level which is intended for research purposes. This second edition cancels and replaces the first edition published in 1966. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) the structure of the standard takes into account the current style of IEC standards; b) this document is no longer a “Recommendation” but an “International Standard”; c) the test installation is no longer related to gas-pressure and oil-filled cables only; d) switching-impulse voltage and superimposed impulse voltage tests have been included; e) for the measuring system the reference to IEC 60060-2 has been added. The reference to the sphere gap method has been moved to Annex B.