Low voltage cable

Low voltage cable construction

It is composed of wire core, insulating layer and protective layer.A wire core is used to conduct current and is usually made of strands of copper or aluminum.Low - voltage cable has a single - core, two - core, three - core, four - core and other types.Two-core cable is used for single-phase line, three-core and four-core cable is used for three-phase three-wire line and three-phase four-wire line respectively, single-core cable can be used for single-phase line or three-phase line as required.The cross-sectional area of common low-voltage cable cores is 10,16, 25, 35, 50, 70, 95, 120,150, 185, 240 mm, etc.

Insulating layer

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An insulating material in a cable having a specific function of withstanding voltage.Insulation layer is divided into core insulation and insulation with two kinds: coated online core insulation is called core insulation;Insulated cores of multiple cables are combined and covered with insulation called tape insulation.With insulation and protective layer separated form a reliable ground insulation.Insulation layers are usually made of oil-impregnated paper, plastic, rubber, etc.

(1) paper insulated cable is the cable with impregnated cable paper as the insulating layer, which is generally referred to as paper insulated cable.According to the paper impregnation situation can be divided into: 1.(2) dry insulated cable;(3) drip cable.

(2) the insulation layer is made of thermoplastic extruded and cross-linked cables, which are generally called plastic cables and are widely used.Plastic cable can be divided into PVC cable, polyethylene cable and crosslinked polyethylene cable, such as three kinds.The cable made of natural styrene butadiene rubber, butyl rubber and ethylene-propylene rubber as insulation layer is called rubber cable.Paper insulated cables and plastic cables can be used for low-voltage cables with voltage grade of 1kV, and more plastic cables are used.The low voltage cables with voltage grade of 0.5 kV are mostly rubber cables.[1]

Protective layer

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A layer or layers of metal or nonmetallic material covering the outside of a cable.The protective layer is used to protect the insulating layer from external force damage and moisture intrusion during transportation, laying and use.

(1) paper insulated cable protective layer.The paper insulated cable protective layer is divided into two parts: inner sheath and outer sheath.The inner protective layer is directly squeezed on the insulating layer. In addition to protecting the insulation from moisture, it also has the function of preventing the insulating oil from flowing out and has certain mechanical strength.There are three kinds of inner cladding: lead cladding, aluminum cladding and PVC cladding.The outer sheath protects the inner sheath to increase the cable's resistance to mechanical forces and corrosion.The outer sheath includes an inner liner, a metal armor layer and an outer coat.The inner liner protects the metal sheath from being damaged by the metal armor layer, and anti-corrosion measures can be added.Metal armor layer can withstand external mechanical forces;The outer coat protects the armored metal from external corrosion.

(2) plastic cable protective layer.Polyvinyl chloride sheath is usually used outside the plastic insulation.

(3) protective layer of rubber cable.The protective layer of rubber cable is divided into inner sheath and outer sheath.The inner sheath includes PVC sheath, neoprene sheath (non-combustible rubber) and lead sheath.The outer sheath is divided into steel belt armoring, rubber sheath and plastic sheath.

The rated voltage of the product is (U0/U)0.6/1---26/35kv for power line transmission and distribution

Second, use 1. The highest rated temperature of the cable conductor is 90 ° C, short circuit (the longest...