Applicable to locking devices used with ball and socket couplings of string insulator units and used with the corresponding metal fittings standardized in IEC 60120. -Defines the shapes and some standard dimensions for locking devices as well as the test methods for locking devices; -States the acceptance conditions for supply and gives other dimensions for guidance of manufacturing only. Replaces IEC 60372-1 (1977) and 60372-2 (1976).