Wires are conductive metal wires used to carry current. They have various forms such as solid, twisted, and foil. The insulated conductor formed in the sheath has a larger size and a more complicated structure.

There is no strict boundary between "wire" and "cable" in life. Usually, products with few cores, small diameter and simple structure are called wires, those without insulation are called bare wires, and others are called cables. The larger one (greater than 6 square millimeters) is called a large cable, the smaller one (less than or equal to 6 square millimeters) is called a small cable, and the insulated cable is also called a building wire.

                                                           
Difference between cable and wire
1. Wires and cables are generally composed of three parts: core wire, insulating sheath and protective sheath. The wire is composed of more than one soft wire and a light and soft sheath; while the cable is more than one insulated wire and metal or rubber. Made of tough outer layer.
2. Wires refer to products with fewer cores, small diameters, and simple structures; wires without insulation are bare wires; cables generally have more than two layers of insulation, and the structure is more complicated. Most cables use multi-core junctions. design.
3. Due to the limited area, electric wires can only transmit relatively small power; while cables are usually used to transmit relatively large electric currents due to their strong bearing capacity.
4. The hardness of the wire is low; the hardness of the cable is high.

What should be paid attention to when purchasing wire and cable?
1. Wire and cable raw material itself and structure
The first thing to consider for wires and cables is how many cores are needed. The more common ones are 1 core, 2 cores, 3 cores, 4 cores, and 5 cores. The second is the selection of the protective layer of the wire and cable, usually with a metal protective layer and a shielded cable protective layer. As for the materials of wire and cable, copper and aluminum are more widely used in engineering projects, commonly known as "copper core wire" and "4/0 aluminum wire".
In addition, the insulation performance of the wire and cable is also one of the considerations, that is, the long-term allowable operating temperature of the wire and cable under the condition of the insulation layer, with the same rated power, the section of the wire and cable with high heat resistance can be relatively smaller .
2. Output power
The greater the power, the larger the cross-section of the wire and cable needs to be selected, and the power determines the selection of the cross-sectional size of the wire and cable.
3. Spacing regulations for power distribution
If the power distribution distance is relatively far, the line damage and current flow of the entire route must be considered. In order to reduce the current flow, the cross-section of the wire and cable can be considered.
4. The use environment and ambient temperature of wires and cables
The use environment and ambient temperature of wires and cables have a great relationship with the selection of cross-sections of wires and cables. In indoor ventilated areas, the operating environment temperature is lower, and the cable ampacity of wires and cables is higher. If the gas is not circulated, the operating environment The temperature is high, the cable is easy to get hot, and the cable ampacity is very low, so we usually refer to paying attention to the heat dissipation of the cable.

Selection of cable ampacity:
1. Cable ampacity - that is, the total current flow of the wire and cable under the condition of power distribution.
2. To ensure the long-term service life of wires and cables, the ambient temperature of wires and cables used in power distribution operations should not exceed the long-term allowable operating temperature of wires and cables.