There must be something you don’t know about wires and cables

    For beginners, wires and cables are always a bit silly to distinguish between wires and cables. Wire refers to a wire that conducts current, which can effectively conduct current and is a carrier for conducting electricity. Cables are wire products used to transmit electricity (magnetic) energy, information, and realize the conversion of electromagnetic energy. They are usually composed of several or several groups of wires. They are divided into: power cables, control cables, compensation cables, shielded cables, high-temperature cables, Computer cables, signal cables, coaxial cables, fire-resistant cables, marine cables, mining cables, aluminum alloy cables, etc. What is the difference between the two? What types of wires and cables are there? Where are they used? This time, Polaris Power Transmission and Distribution Editor will take you into the world of wires and cables. What is the difference between wire and cable?

    1. The wire is composed of one or several soft wires with a light and soft sheath; the cable is composed of one or several insulated wires, and the outside is covered with a tough outer layer made of metal or rubber. Cables and wires generally consist of three parts: core wire, insulating sheath and protective sheath. In fact, there is no strict boundary between "wire" and "cable". Generally, products with a small number of cores, small product diameters, and simple structures are called wires, those without insulation are called bare wires, and the others are called cables. The conductor with a larger cross-sectional area (greater than 6 square millimeters) is called a large wire, and the smaller one (less than or equal to 6 square millimeters) is called a small wire, and the insulated wire is also called a cloth wire.

    2. Cables generally have more than two layers of insulation, most of which are multi-core structures, wound on the cable reel, and the length is generally greater than 100 meters. Wires are generally single-layer insulated, single-core, 100-meter rolls, wireless disks.

    3. The smaller diameter is called "line"; the larger diameter is called "cable".

    4. Simple structure is called "line"; complex structure is called "cable".

    But with the expansion of the scope of use, many varieties "cable in the cable" and "cable in the cable". So there is no need to make a strict distinction. In daily habits, people call household cloth wires a wire, and power cables abbreviate to cables.

    What types of wires are there? Where are they used?

    1. Type BLX and Type BLV: Aluminum core wires, due to their light weight, are usually used for overhead lines, especially long-distance transmission lines.

    2. Type BX and Type BV: Copper core wires are widely used in electromechanical engineering and are suitable for the fixed laying of power plants of 450/750V and below. However, because the production process of rubber insulated wires BX is better than PVC insulated wires BV Complicated, and some chemical components in rubber-insulated insulation have a chemical effect on copper. Although this effect is slight, it is still a defect, so it is basically replaced by the BV type of PVC insulated wire in electromechanical engineering.

    3. RV type and RX type: Copper core cords are mainly used in movable parts that require flexible connection. RV type is suitable for household appliances, small electric tools, instruments and meters of 450/750V and below, and the allowable working temperature for a long time should not exceed 65°C. RX type is suitable for indoor lighting fixtures, household appliances and tools of 300/500V and below, and the allowable working temperature should not exceed 70°C.

    4. BVV type: Multi-core flat or round plastic wire, which can be used for wiring in electrical equipment. It is often used in fixed wiring in household appliances, but the model is not the BVV hard wire used for conventional wiring, but RW, It is a copper core plastic insulated plastic sheathed multi-core flexible cord. For example, general home and office lighting usually use BV or BX type PVC insulated or rubber insulated copper core wire as the power connection line; the connection from the electric welding machine to the welding tongs in the electromechanical engineering site is mostly RV type PVC insulated Copper core flexible wire, this is because the welding position is not fixed, and it moves more.

    What types of cables are there? Where are they used?

    1. Type VV and YJV: PVC type power cable, cross-linked polyethylene type power cable, can not be subjected to mechanical external force, suitable for indoor and tunnel bridge and pipeline laying. For example, the cross-Huangpu River power cable laid in the Dalian Road Tunnel in Pudong New Area uses a YJV copper core XLPE insulated PVC sheathed cable, because the cable will not be subjected to mechanical external forces in the tunnel, and it is not required Withstand large pulling forces.

    2. Type VV22 and YJV22: inner steel tape armored power cables, which can bear certain mechanical external forces, but cannot bear large tensile forces. The YJV22 type cross-linked polyethylene insulated power cable allows a maximum high temperature of 90°C for a long time. It has higher aging resistance and environmental resistance than the PVC insulated cable VV22, and has light weight, simple structure, convenient use, and no drop in laying. limit. Such as laying indoors, tunnels, cable trenches and directly buried underground in high-rise buildings, hospitals, subways, nuclear power plants, power plants, mines, petroleum, chemical industries, etc.

    3. Type ZR-YJFE, NH-YJFE: flame-retardant, fire-resistant and other special radiation cross-linked power cables. The maximum long-term allowable working temperature of the cable can reach 125°C. It can be laid in the suspended ceiling or in the cable shaft of high-rise buildings. , And suitable for wet places. Flame-retardant cables should have flame-retardant properties. In order to extinguish, reduce or inhibit the burning of the material, 11 kinds of commonly used materials and engineering equipment must be added to the material or the material must be processed. Usually, a flame retardant is added to the material to make the material It has the function of preventing or delaying the spread of flame during combustion. That is, it burns on an open flame and extinguishes automatically after leaving the fire for a period of time. There are currently four levels of A, B, C, and D, and C level is generally used.

    The characteristic of fire-resistant cable is that it still has the ability to conduct electricity when the cable is burned or even for a period of time after burning. It is mostly used in relatively important working environments, such as warships. Fire-resistant cables can have flame-retardant properties at the same time, but flame-retardant cables do not have fire-resistant properties.