Wire and cable are mainly composed of three basic structural components: conductive core, insulation layer and sheath layer.

There is no strict limit between the wire and the cable, but in general, the cable structure is more complicated, it has a complicated sheath layer, and the wire structure is relatively simple. There are only conductors and insulation layers, and some are only woven and coated. Lightweight cover or covered with a light soft cover. The conductive core of wire and cable is used to transmit current. In order to reduce the power loss and voltage drop, the conductive core is generally made of copper and aluminum with high conductivity. The role of the insulation layer is to prevent current leakage in the radial direction, to ensure safe use. Therefore, the insulation layer is required to have good electrical insulation properties. Heat resistance and certain mechanical strength.

The protective cover layer on the outside of the insulated core or the cable core is called the sheath of the cable (the protective cover on the outside of the cover is called the outer cover). The main role of the sheath is to protect the insulation. Its main performance is moisture, oil and corrosion. Anti-sunlight aging, flame resistance, and mechanical protection (the role of the outer sheath is mainly to strengthen

Mechanical protection of the cable. It bears tensile force and bumping), and also has anti-electricity, anti-magnetic dry resistance, etc.

From the perspective of wire and cable sheathing, weaving is one of many types of sheaths or outer sheaths for wire and cable. However, according to the materials used in the wire and cable braid and the different parts of the braid in the wire and cable structure, the effect of the braid is obviously different.

First, the role of fiber braid

For wires, the fiber braid is a form of its lightweight protective layer. Its main function is to protect the insulation from or under all kinds of light, heat and moisture. Erosion of low temperature, acid and alkali gas, and damage from external mechanical forces ensure the safe operation of the wires. For cables, the fiber woven layer is often in the middle of the sheath to enhance the tear strength of the sheath. For example, the reinforced jacket is to add cotton yarn, hemp and other fiber woven layers in the middle of the rubber or plastic sheath to improve The strength of the sheath.

Second, the role of metal braid

The metal braid mainly consists of a copper wire braid and a steel wire (wire) braid.

The main functions of copper wire weaving are:

l-Shielding effect against electromagnetic interference, such as tinned copper wire braided blue cable, copper wire braided control cable, etc.

2. Eliminate the shielding effect of the surface potential of the power cable. It binds the power line and eliminates the induction of electricity, such as the total shielding of high-voltage cables.

3. The shielding effect of security protection. The copper wire is woven outside the main core insulation and is in good contact with the core or used as a ground wire to timely react to leakage, such as shielded mining cables.

The main role of steel wire weaving is:

l. Mechanical protection. Such as marine power cable CF31 type.

2. Longitudinal breaking force, such as magnetic measuring cable for marine geological exploration WC-GC, WCT type.

3. Magnetic field shielding.