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.

1、 Bare wire is a kind of wire without insulation, which is mainly used for outdoor overhead.

2、 Electromagnetic wire refers to the wire used on the electromagnetic coil, all of which are electromagnetic wires. Electromagnetic wire has a high requirement for wire technology, which needs to adapt to strong vibration, centrifugal, high temperature, corrosion and other harsh environment.

3、 Power cable is mainly used to transmit and distribute electric energy. The utility model is characterized in that oil paper, rubber or plastic are wrapped on the conductor. The cable has strong corrosion resistance and insulation ability, can withstand high voltage, and has low requirements for use environment.

4、 Wires and cables for electrical equipment are commonly used in daily life, which are mainly used to assemble electrical equipment and instruments, and to separate electric energy.

5、 Communication cable is mainly used for the transmission of television, telephone, network, broadcast signal, etc., with the characteristics of large signal capacity and strong anti-interference ability.

Cable trays are divided into three categories:

1. Ladder straight through bridge is generally used for large diameter cables such as power cables.

2. Trough type straight through bridge, generally used for network, communication, fire protection and other aspects of communication cable.

3. Tray type straight through bridge is widely used for power cables and signals.

Electrical accessories required for cable laying include cable terminal box, cable intermediate box, connecting pipe and terminal, steel plate wiring slot, cable tray, etc.

When selecting wires and cables, we should generally pay attention to these problems:

1. The rated voltage of the conductor is 1.5 times higher than the actual voltage.

2. The current carrying capacity of the conductor is generally more than 1.5 times of the actual current.

3. The voltage drop should be calculated according to the length of the long line.

4. The conductor needs to bear the voltage and current when the protection device is running.