How to choose power cables correctly? How to choose power cables?

Power cables are used to transmit electrical energy. Power cables are composed of one or more wires and are widely used in factories, households, overhead, underwater, and underground. Some are rigid, while others are flexible. So, how to choose power cables?

The selection of power cables should be considered from the following aspects:

1. Voltage

Each cable and its conductor have resistance. This is inversely proportional to the diameter of the conductor and directly proportional to the length of the conductor. Roughly speaking, this means that in thicker and longer cables, the resistance will be lower. As the current flows, there is also a voltage drop in the cable. In slender cables, this may also be a major factor determining the total length. The voltage drop shall not exceed 2.5% of the provided voltage. This is usually the factor determining the length.

2. Current

Determine the current carrying capacity of the cable. When the current carried by a cable exceeds the normal current, it will overheat. The size of the cable is also an important factor. Carefully consider the length allowed by the current carrying capacity.

3. Short circuit power

The required conductor size in a device is determined by its short-circuit current carrying capacity rather than its continuous current carrying capacity, and the short-circuit current carrying capacity is determined based on the open circuit time under short-circuit conditions. This basically means that before using the switch device, the cable should be able to withstand or contain thermal damage caused by a short circuit.

4. Installation environment

When choosing cables, the installation environment of the cables should also be considered, and the required cables should be selected according to the installation environment. In unfavorable environmental conditions, such as underground or exposed to sunlight, we need cables with mechanical strength.

5. Shielded or not

Not every cable needs to be shielded. The main factors that determine whether shielding is necessary are the insulation system, grounding system, and their properties. In shielded cables, insulation can be damaged when handling medium to high voltages.

6. Insulation

Common insulation materials include PVC, XLPE, and rubber. The selection of insulation is based on factors such as temperature range, load, installation type, and corrosive factors.