As the main material for electricity and electrical transmission, cable wires are closely related to our lives and play an irreplaceable role in our lives. Everyone encountered many problems during the selection process. Today, learning this knowledge with everyone will help to better choose and use cable products safely.
1. Understand the classification and characteristics of various wires and cables. It can be divided into bare wires, insulated wires, heat-resistant wires, shielded wires, power cables, control cables, communication cables, radio frequency cables, etc. Common insulated wires includePVC insulated wires, PVC insulated cords, NBR PVC mixed insulated cords, rubber insulated wires, plastic insulated wires with aluminum core directly buried in agricultural underground, rubber insulated cotton yarn braided cords, PVC insulated nylon sheathed wires , PVC insulated cords for electric lighting, etc. Low-voltage power cables can be divided into oil-impregnated paper-insulated lead-clad (or aluminum-clad) power cables, oil-impregnated paper-insulated power cables, PVC insulated and PVC sheathed power cables, cross-linked PVC insulated and polyethylene sheathed power cables, and cross-linked PVC insulated PVC sheathed power cables and rubber insulated power cables.
2. The characteristics that the national standard cable should have. The inner and outer sheath of the cable should meet the requirements of the national standard, and the outer sheath should protect the inside of the cable from mechanical damage and chemical corrosion, and enhance the mechanical strength. Inner protective layer: prevent the insulation layer from contacting water, air or other objects, and prevent the insulation layer from being damp and mechanically damaged. The material should have high breakdown strength, low dielectric loss, high insulation resistance, excellent discharge resistance, certain flexibility and mechanical strength, and long-term stable insulation performance.
3. Several principles should be followed when selecting cables. The rated voltage of the cable should be greater than or equal to the rated voltage of the power supply system at the installation point, and the continuous allowable current of the cable should be equal to or greater than the maximum continuous current of the power supply load. The cross-section of the core should meet the stability requirements of the power supply system in the event of a short circuit. Check whether the voltage drop meets the requirements according to the cable length, and the minimum short-circuit current at the end of the line should enable the protection device to operate reliably. Understand the influencing factors of cable current carrying capacity, laying environment, temperature and heat dissipation factors, and make better choices. For the safety of people's lives and property, cables need to choose regular cable manufacturers and choose national standard products.