Types of cable insulation, what's the difference between them? And the explanation of wire and cable knowledge
The insulating layer of the cable is used to isolate the multi-core conductors and the conductors and the sheath from each other, and to ensure a certain electrical withstand voltage strength. It has certain heat resistance and stable insulation quality.
The materials of the insulating layer are mainly oil-impregnated cable paper, plastic and rubber. According to the different materials used for the conductor insulation layer, cables are mainly divided into plastic insulated cables, rubber insulated cables and oil-impregnated paper insulated cables.
Plastic insulated cable: There are two kinds of PVC insulation and cross-linked polyethylene insulation. The cable insulation layer is made of thermoplastic plastic extruded and cross-linked after extrusion of thermoplastic polyethylene with cross-linking agent. This insulation has good electrical properties and water resistance, and can resist acid, alkali, and corrosion. It also has the advantages of high allowable working temperature, good mechanical properties, and the ability to manufacture high-voltage cables.
Rubber insulated cable: The insulation layer of rubber insulated power cable is styrene-butadiene rubber or synthetic rubber (ethylene propylene rubber, butyl rubber). The main features of this type of cable are that it is soft and flexible, and is suitable for use in mobile electricity and related power supply devices. Under the action of high voltage, the cable is easily cracked by corona. Therefore, the cable is generally used for the voltage level of 10KV and below, and the synthetic ethylene-propylene rubber insulated cable can be used for the voltage level of 35KV.
Oil-impregnated paper insulated cable: It is composed of cable paper and impregnating agent. A part of insulating paper is wound on each conductor, and several conductors are twisted together. In addition, a certain thickness of cable paper is wrapped around the conductor. Between the conductor insulation thickness is doubled; between the conductor and the lead sheath is the conductor insulation thickness plus the total package insulation thickness.
Regarding the difference between the allowable long-term working temperature of the cable insulation in the wire and cable core, the general rubber insulated cable is 65°C, the PVC insulation is 70°C, and the cross-linked polyethylene insulation is 90°C. The maximum allowable temperature of the conductor in the short term (the maximum duration does not exceed 5s), the PVC insulation is 160°C, and the XLPE insulation is 250°C. The normal operating temperature of oil-impregnated paper insulation can reach 80°C, but its flexibility is poor, so the minimum allowable bending radius and minimum laying temperature of the cable are specified.
Overhead Insulated Cable
The overhead insulated cable is between the overhead conductor and the power cable in terms of performance. It must not only meet the requirements of the mechanical strength of the overhead conductor, but also meet the performance requirements of the power cable.
Overhead insulated cables are divided into single-core overhead insulated cables, multi-core overhead insulated cables, and parallel bundled overhead insulated cables.
The frequency conversion cable has a metal shielding layer structure, and the shielding layer must be able to effectively suppress electromagnetic radiation.
It is suitable for power devices with rated voltages of 300/300V, 300/500V, 450/750V and below, fixed wiring, household electrical appliances, instrumentation, power lighting, elevator equipment, electronic equipment and other automation devices.
This article mainly describes the three major types of cable insulation. You should also refer to the standards of various industries when consulting products. Zhengzhou Jinshui Wire and Cable has always provided you with the best quality cable products in the industry.