In the overhead distribution line, the metal appliance used to connect and fasten the conductor, and the metal components with the functions of conductivity, bearing and fixing are fittings. According to their performance and use, fittings can be divided into line clamps, connecting fittings, splicing fittings and protective fittings.
The opening wedge-type strain clamp is more convenient to install the conductor, which is suitable for installation after the insulation layer is stripped from the insulated conductor ( can prevent lightning from breaking the line), and an additional insulation cover is added. The opening wedge-type strain clamp is shown in Figure When used with copper strands or insulated copper strands, the clamp is generally made of ductile cast iron and the wedge is made of brass. When used with aluminum strands or insulated aluminum strands the clamp and wedge are made of high-strength aluminum alloy.
The body and the pressure plate of the bolt type strain clamp are made of ductile cast iron because of its low cost, and it is widely used. It suitable for the terminal of the line or where the current does not flow through the line clamp, Bolt type strain clamp (ductile cast iron). The bolt type aluminum alloy clamp is made of high-strength aluminum alloy, which has energy-saving effect.
Pre-twisted strain hardware, which is structured with pre-twisted legs to form an empty tube, pre-formed twisted rings at the bending, and pre-twisted strain clamps. The pre-twisted wire is wound around the conductor, and with the help of the elasticity of the material and the tightening, it becomes tighter and tighter without slipping. The twisted ring is placed on the heart-shaped ring and connected to the suspended insulator. Generally, the pre-twisted strain clamp right-handed, consistent with the direction of the twisted line, and is usually coated with quartz sand to increase friction. Pre-twisted strain clamps for 10V insulated conductors are made of galvanized steel wire and can be directly installed on the outer insulation layer of the insulated conductor. Pre-twisted strain clamps aluminum conductors are made of high-strength aluminum alloy single wire conductors, and pre-twisted strain clamps for steel strand tensioning are made of galvanized steel.
