The waterproof cable
Waterproof cable, as the name suggests, the outer skin and filling of the cable are made of waterproof rubber, and the sheath of the cable is also made of waterproof rubber sheath. Generally, waterproof cables are suitable for submersible pumps, coal mines, underwater operations, underwater landscape lights and other water treatment equipment. So what are the specific types of waterproof cables and what are their characteristics? Let's have a look.
1、 Ethylene propylene rubber insulated waterproof cable
Due to the superior insulation performance without "water tree" phenomenon, ethylene propylene rubber insulated cables are widely used in medium and low voltage underwater transmission lines. For example, waterproof rubber sheathed cable (JHS type) can operate safely in shallow water for a long time.
2、 XLPE insulated waterproof cable
Because the cross-linked polyethylene material is particularly sensitive to water, if the insulation is soaked with water during manufacturing and operation, it is prone to "water tree" breakdown, which greatly shortens the service life of the cable. Therefore, XLPE insulated cables, especially medium and high voltage cables under AC voltage, must have "water blocking structure" when used in water environment or humid environment. The so-called "water blocking structure" includes radial water blocking structure and longitudinal water blocking structure.
Longitudinal water blocking
Longitudinal water blocking commonly used are water blocking yarn, water blocking powder and water blocking belt. Their water blocking mechanism is that these materials contain a water expandable material. When water enters from the cable end or sheath defects, this material will expand rapidly in case of water to prevent further diffusion of water along the longitudinal direction of the cable, so as to achieve the purpose of longitudinal waterproof of the cable.
Radial water blocking
Radial water resistance is mainly realized by squeezing HDPE non-metallic sheath or hot pressing, welding and cold drawing metal sheath.