Basic knowledge about wires and cables
Wires and cables are mainly divided into five categories: bare wires, electromagnetic wires, power cables, wires and cables for electrical equipment, and communication cables. Different types of wires and cables have different definitions and functions. Next, let's take a look at the common types of wires and cables.
Bare wire is a kind of wire without insulation wrap, mainly used for outdoor overhead.
Electromagnetic wire refers to the wire used on the electromagnetic coil, all of which are electromagnetic wire. Electromagnetic wire has high requirements on wire technology, and needs to adapt to harsh environments such as strong vibration, centrifugation, high temperature, and corrosion.
Power cables are mainly used to transmit and distribute electrical energy. It is characterized by wrapping oil paper, rubber or plastic on the conductor. The cable is corrosion-resistant, strong in insulation, can withstand high voltage, and has low requirements for the use environment.
Wires and cables for electrical equipment are commonly used wires in daily life, mainly used to assemble electrical equipment and meters, and to shunt electrical energy.
Communication cables are mainly used for the transmission of television, telephone, network, broadcast signals, etc., and have the characteristics of large signal capacity and strong anti-interference ability.
There are three types of cable trays: step-through trays, which are generally used for large diameter cables such as power cables. Slot-type straight-through bridge is generally used for communication cables in network, communication, fire protection, etc. Tray-type through-bridge is used for power cables and signals, and has a wide range of applications.
The electrical accessories required for laying cables include cable terminal junction boxes, cable intermediate junction boxes, connecting pipes and terminals, steel plate connection slots, cable trays, etc.
When choosing wires and cables, we should generally pay attention to these issues:
1. The rated voltage of the wire is 1.5 times higher than the actual voltage.
2. The current carrying capacity of the wire is generally more than 1.5 times the actual current.
3. When laying long cables, calculate the voltage drop according to the length.
4. The wire needs to withstand the voltage and current when the protection device is operating.