This international standard is 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, when they are supplied separately.

When these locking devices are supplied with an insulator or fitting, they are considered as an integral part of it. In this case, the relevant test is to be included with those of insulators, as specified in IEC 60383-1 and IEC 61325. On request, a certificate is to be delivered confirming that the tests on locking devices as specified in this document have been carried out. The locking devices are usually supplied with the insulator or corresponding metal fittings.

The object of this document is

• to define the shapes and some standard dimensions for locking devices,

• to define the test methods for locking devices,

• to state the acceptance conditions for supply,

• to give other dimensions for guidance of manufacturing only.

The object of this document does not include the specification of the nature of the material, and the material covered by the scope of this document does not have a surface coating for corrosion protection. However, the material which will give rise to significant contact corrosion(chemical reaction) between the locking device and the ball and socket coupling does not covered by this document.