P&B Weir Electrical Ltd manufacture Substation Operating Sockets, the S9D ESI S1 and the CEA/S2 ESI-S2, using a light alloy material for both strength and ease of use. These essentially support the line end clamp while being raised and lowered at the end of an operating pole and also rotate the operating screw of the line end clamp whilst being secured into position or being removed. Socket type S9D ESI S1 supports clamps being applied in an upward direction. When the clamp is fully tightened the socket should be pushed gently up towards the clamp at the same time maintaining the tightening pressure and to which the socket will then automatically disengage. Socket type CEA/52 ESI-S2 is an alternative type to the S9D where the operating screw of the line end clamp is controlled by means of a sprung loaded plunger in the socket. This socket is for application in a downward direction i.e. below the horizontal and for this reason is sprung loaded to ensure the clamp does not fall out of the socket inadvertently.