In addition to conductors, the basic components of wires and cables also include insulating layers, protective layers, shielding layers, and sheathing layers. Among them, the insulating layer is to insulate the conductors in the cable from the surrounding environment or adjacent conductors, to ensure that the current or electromagnetic waves and light waves transmitted by the conductor core only propagate along the wires and do not flow to the outside world, while ensuring the safety of external objects and personnel. Cable insulation materials can be roughly divided into plastic insulation materials and rubber insulation materials, which have their own characteristics and uses. Ethylene (PVC), polyethylene, cross-linked polyethylene (XLPE), low-smoke halogen-free (WD), among them, cross-linked polyethylene is widely used in the insulation of medium and high voltage cables due to its excellent electrical and mechanical properties; Rubber insulated power cables, as the name suggests, are cables made of rubber and various compounding agents after processing. The rubber materials commonly used for insulation are natural rubber-styrene-styrene rubber mixture, ethylene-propylene rubber, butyl rubber, etc., It is soft and elastic, suitable for frequent movement, and has the advantages of small bending radius.
The cable protective layer is a protective covering layer applied on the outside of the cable insulation layer, called the cable protective layer (sheath), in order to adapt the cable to the requirements of various use environments. The main function of the cable protective layer is to protect the cable insulation layer from mechanical damage and various environmental factors, such as water, sunlight, biology, fire, etc., during the laying and operation process, so as to maintain the long-term stable electrical performance of the cable. Therefore, The quality of the cable protective layer is directly related to the service life of the cable. The cable protective layer can be mainly divided into three categories: the metal protective layer (including the outer protective layer), the rubber-plastic protective layer and the combined protective layer. effect of corrosion. However, it is worth noting that if the cable protective layer is too long, it will also generate heat during use. If the time is longer and everyone does not pay attention, it will cause a fire. Therefore, the length of the cable protective layer Should be moderate.
