According to the insulation materials are divided into the following three categories:
1, oil immersion paper insulated power cable electrical cable insulated by oil immersion paper. Its application history is long. It is safe and reliable, has a long service life, and is cheap. The main lack is that the laying is limited by the drop. Since the development of non-drip immersion paper insulation, the problem of drop limit has been dealt with, so that the oil immersion paper insulation cable can continue to be widely used.
2, plastic insulated power cable insulation layer for extrusion of plastic power cable. Common plastics are polyvinyl chloride, polyethylene, cross-linked polyethylene. The structure of plastic cable is relatively simple, easy to manufacture, light weight, easy to install, and is not limited by the drop of laying. Therefore, it should be used as a medium and low voltage cable, and there is a tendency to replace viscous impregnated oil paper cables. Its great disadvantage is the presence of dendritic breakdown, which limits its use at higher voltages.
3, rubber insulated electric cable insulation layer for rubber plus a variety of binders, should be fully mixed after the process of extrusion on the lead wire core, after heating and vulcanization. It is soft and elastic, suitable for frequent movement and small bending radius.