Low-voltage cable structure: composed of three parts: core, insulation layer and protective layer. The wire core is used to conduct current and is generally twisted by multiple strands of copper wire or multiple strands of aluminum wire. Low voltage cable has single core, double core, three core, four core and so on. Two-core cables are used for single-phase lines, three-core and four-core cables are used for three-phase three-wire lines and three-phase four-wire lines, respectively, and single-core cables can be applied to single-phase or three-phase lines as needed. Commonly used low-voltage cable core cross-sectional area of 10,16, 25, 35, 50, 70, 95, 120,150, 185, 240 mm and so on.

Insulating layer

An insulating material in a cable that has a specific function to withstand voltage. The insulation layer is divided into two types: core insulation and band insulation: the insulation coated on the online core is called core insulation; The insulation of the insulated wire core of a multi-core cable is called tape insulation. With insulation and protective layer separated to form a reliable ground insulation. The insulation layer is usually made by dipping paper, plastic, rubber, etc.

(1) Paper insulation cable is a cable made of impregnated cable paper as an insulating layer, collectively known as paper insulated cable. According to the situation of paper impregnation, it can be divided into: ① oil-impregnated paper insulated cable; ② Dry insulated cable; ③ non-dripping cable.

(2) The insulation layer is made of thermoplastic extruded cross-linked cables, collectively known as plastic cables, which are widely used. Plastic cables can be divided into polyvinyl chloride cables, polyethylene cables and cross-linked polyethylene cables. Cables with natural styrene butadiene rubber, butyl rubber and ethylene propylene rubber as insulating layers are called rubber cables. Low-voltage cables with a voltage class of 1kV can use paper insulated cables and plastic cables, and more plastic cables are used. Low voltage cables with voltage class of 0.5 kV are mostly rubber cables.

Protective layer

A layer or layers of metal or non-metal material covering the outer part of a cable. The protective layer is used to protect the insulation layer from external damage and water intrusion during transportation, laying and use.

(1) Paper insulated cable protective layer. The paper insulated cable protective layer is divided into two parts: inner protective layer and outer protective layer. The inner protective layer is directly extruded on the insulation layer, which in addition to protecting the insulation from moisture, also has the effect of preventing the outflow of insulation oil, and has a certain mechanical strength. The inner cover has three kinds of lead, aluminum and polyvinyl chloride. The outer protective layer protects the inner protective layer to increase the cable's ability to withstand mechanical external forces and corrosion resistance. The outer protective layer includes an inner liner layer, a metal armor layer and an outer coating layer. The inner liner layer protects the metal sheath from being damaged by the metal armor layer, and can add anti-corrosion measures; Metal armor layer can withstand mechanical external force; The outer coating protects the armored metal from external corrosion.

(2) Plastic cable protective layer. PVC sheathing is usually used over plastic insulation.

(3) Protective layer of rubber cable. The protective layer of rubber cable is divided into inner protective layer and outer protective layer. The inner cover has three kinds: polyvinyl chloride sheath, neoprene rubber sheath (non-combustible rubber) and lead sheath; The outer sheath is divided into three kinds: steel tape armor, rubber sheath and plastic sheath.

Model selection

The selection of power cable models should be determined according to environmental conditions, laying methods, special requirements of electrical equipment and other factors, generally considered in accordance with the following principles:

(1) Aluminum core cables should be used in general environments and places, but copper core cables should be used in places with intense vibration and special buildings and special requirements.

(2) Buried cables are generally armored cables with outer protective layers. In places where there is no possibility of mechanical damage, plastic-sheathed cables and lead (aluminum) clad cables with outer sheathing can also be used.

(3) In the soil with chemical corrosion or stray current corrosion, buried cables should not be used as far as possible. If it must be buried, anti-corrosion cables should be used.

(4) Cables laid in tubes or tubes are generally plastic sheathed cables, and bare armored cables can also be used.

(5) The cable laid in the cable trench or cable tunnel should not be flammable or flammable outer protective layer. Generally, bare armored cables, plastic sheathed cables and bare lead (aluminum) covered cables are used.

(6) When the cable is laid in a place with a large height difference, it is appropriate to use plastic insulated cables, non-dripping cables and dry insulated cables.

The cross-sectional area of the cable should be selected according to the following four conditions: ① according to the heating conditions; ② Select according to the allowable voltage loss; ③ Select according to mechanical strength conditions; ④ Select according to the line protection (device) equipment. (See Low voltage line)

Low voltage cable line

Low voltage line with cable. The cable is composed of a core, an insulating layer and a protective layer. There are many types of cables, and low-voltage cable lines mainly use low-voltage power cables.

The commonly used laying methods of low-voltage cable lines are: ① directly buried; ② Laid in the cable trench; ③ Laying along the wall; ④ Laid in the cable tunnel, etc. The type of low-voltage power cable is mainly selected according to the environmental conditions and laying methods. Compared with low-voltage overhead lines and low-voltage overhead insulated lines, although the cost is higher and the installation and maintenance is more difficult, the low-voltage cable line has been widely used in the low-voltage distribution system because it has the characteristics of reliable operation, no pole, no ground occupation, no visual obstruction, and little external influence. Low-voltage cable lines are mainly used in places that have high requirements on power supply reliability (see Power supply quality), corrosive gases, inflammable, explosive, and so on, where it is not appropriate to erect low-voltage overhead lines or low-voltage overhead insulated lines.

Qingdao Tianxing Cable Co., Ltd. focuses on the production of customized wire and cable manufacturers, main: fire wire and cable, power cable, control cable and other products, exported to more than 40 countries and regions around the world, the annual production capacity of 1 billion yuan. 6000 square meters of storage, standing hundreds of millions of inventory, order demand for rapid distribution and delivery, large prices more favorable. Hotline: 16678668098