The difference between wire and cable does not have strict limits, but in general terms, the cable structure is more complex, it has a complex sheathing layer, and the wire structure is relatively simple and there are only conductors and insulation layers, and some only woven wax coating Light cover or coated with a light soft sheath. Wire and cable conductive core is used to transmit current. To reduce power loss and voltage drop, conductive cores are generally made of copper and aluminum with high conductivity. The role of the insulating layer is to prevent current leakage in the radial direction, to ensure the use of safety. Therefore, the insulating layer is required to have good electrical insulation properties. Heat resistance and a certain degree of mechanical strength.
The protective covering outside the insulated core or cable core is called the sheath of the cable (the protective covering outside the sheath is called the outer sheath). The main role of the sheath is to protect the insulation. Its main performance is moisture, oil, and anti-corrosion. Anti-sunlight aging, flame resistance, and mechanical protection (the role of the outer sheath is mainly to strengthen the mechanical protection of the cable. It bears tensile force, bump), but also has the function of protection against electricity, anti-magnetic dry and other effects
From the perspective of wire and cable sheaths, weaving is one of many types of sheaths or sheaths for wire and cable. However, according to the materials used in the braiding of the wire and cable 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 layer
For wires, the fiber braid layer is a form of its lightweight protective layer. Its main function is to protect the insulation from all kinds of light, heat, and tide. The erosion of low temperature, acid and alkali gas, etc. and the damage of the external mechanical force ensure the safe operation of the wire. For cables, the fiber braid is often in the middle of the sheath to enhance the tear strength of the sheath. For example, the reinforced sheath is made by adding cotton yarn, hemp, etc. to the middle of the rubber or plastic sheath to increase the strength of the sheath. Cover strength.
Second, the role of metal braid
The metal braiding layer mainly consists of a copper wire braid and a wire (wire) braid.
The main role of copper wire weaving is:
1. 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 plays the role of restraining power lines and eliminating inductive power, such as the total shielding of high voltage cables.
3. The shielding effect of security protection. Braiding the copper wire outside the main core insulation and making good contact with the ground core or for ground wire can timely respond to the leakage situation, such as shielded mining cable
The main role of steel wire braiding is:
1. Mechanical protection effect. Such as marine power cable CF31 type.
2. Longitudinal breaking force, such as WC-GC, WCT type for magnetic geophysical exploration.
3. Magnetic shielding.