Anyone who has worked with wires and cables is more or less aware that the industry distinguishes between nationally standardized and non-standardized wires. Numerous tragic fires caused by non-standardized wires are reported. This issue is not only a problem within the wire and cable industry but also a matter of life and property. First, we need to understand the difference between wires and cables, and second, how should we choose them? The following will explain two key points.
I. The Difference Between Wires and Cables
1) Wires are generally conductive metal wires used to carry electric current. They come in various forms, such as solid, stranded, or braided foil. Based on the insulation, they are categorized as bare wire and insulated wire.
2) Cables are insulated conductors consisting of one or more mutually insulated conductive wires enclosed in a sealed sheath. These may be covered with a protective covering and are used to transmit and distribute electrical energy or transmit electrical signals.
The main difference between cables and ordinary wires is that they are larger and more complex. While wires are generally smaller and simpler in structure, cables are sometimes also included in the broader category of wires.
2. How to choose the model and specifications of cables and wires
1) Specifications of cables and wires
Specifications are composed of rated voltage, number of cores and nominal cross-section.
The rated voltages of wires and control cables are generally 300/300V, 300/500V, and 450/750V;
The rated voltages of medium and low voltage power cables are generally 0.6/1kv, 1.8/3kv, 3.6/6kv, 6/6(10)KV, 8.7/10(15)kv, 12/20kv, 18/20(30)kv, 21/35kv, and 26/35kv.
The number of cores of wires and cables is determined according to actual needs. Generally, power cables are mainly 1, 2, 3, 4, and 5 cores, wires are mainly 1 to 5 cores, and control cables are 1 to 61 cores.
2) Power cable selection should adhere to the following principles:
① The rated voltage of the cable must be greater than or equal to the rated voltage of the power supply system at the installation point;
② The continuous allowable current of the cable must be equal to or greater than the maximum continuous current of the load being supplied;
③ The wire core cross-section must meet the stability requirements of the power supply system during a short circuit;
④ Verify that the voltage drop meets the requirements based on the cable length;
⑤ The minimum short-circuit current at the end of the line must ensure reliable operation of the protective device.
The above is the basic knowledge about wires and cables. Due to the large number and complexity of wire and cable specifications, it is unrealistic to learn all about them at once. To gain an understanding of wires and cables, you can learn about BV and BVR cables, which are commonly used in homes. This can be helpful when choosing wires for your home later.
