Specific introduction to the shielding effect of power cables

The power cable is still a low-voltage cable. If it is high-voltage, there will be a layer of similar resin filling inside. This is an insulating effect. In high-voltage cables, this layer is an important part of the insulation. 

There is no such thing as low pressure. Then there will be something similar to the ribbon on the inside. This is to fix each core of the cable and fill the empty space in the center.

A shielded cable is a cable that consists of a common conductive layer wrapped around one or more mutually insulated wires.
This common conductive layer is the shield of the cable, which is generally composed of braided strands of copper or other metallic aluminum, non-braided spiral-wound copper tape, or a conductive polymer layer.

The shield can be wrapped inside the signal or power conductor, in two ways to play a role in preventing electromagnetic noise interference.

Cable shielding will come in different performance levels, providing different degrees of shielding effectiveness.
There are also many factors that determine the amount of shielding required, such as the electrical application environment, cost (i.e., why pay more for more shielding?) and cable diameter, weight and flexibility... etc.

There are generally two types of shielding for cables: metal foil and braided mesh.
1 Metal foil shields are usually made with a thin layer of aluminum attached to a carrier such as polyester to add strength and make it stronger.
Metal foil provides 100% coverage of the wire and has relatively good shielding properties.
However, because it is so thin, it can be difficult to use, especially when plugging it into a connector.
For this reason, it is not common to ground the entire foil shield, but rather to connect the shield with a disturbance wire.
2 Braided mesh shielding is usually made of bare copper or tinned copper wire braid.
It provides a low-impedance ground path for electromagnetic noise and can be easily docked by crimping or soldering when using connectors.


Braided mesh shields do not provide 100% coverage, as they always have some small gaps in the wire surface coverage.
Depending on the tightness of the weave, woven wire shields typically provide 70 to 95 percent coverage.
However, in general, for fixed-laying cables, 70% shielding coverage is sufficient.

As for the shielding layer, the effect of the shielding layer of the power cable is as follows:

1. It can play a specific grounding maintenance effect. If the cable core is damaged, the leakage current can flow through the shield layer, such as the grounding grid, to achieve safe maintenance.

2. Because the current through the power cable is relatively large, a magnetic field will occur around the current. In order not to affect other components, the shielding layer can shield the electromagnetic field in the cable.

If it is a control cable, the other is no different, just in many local, especially the computer system control cable, the shield here is used to shield the external influence because its own current is very weak and very afraid of the external electromagnetic field.

Polyethylene, polyethylene, cross-linked polyethylene, the difference between polyethylene, PE, a polymer of ethylene, and non-toxic. 

3. Simple coloring, good chemical stability, cold resistance, radiation resistance, and electrical insulation. It is suitable for packaging materials for food and medicine, making utensils, medical equipment, and insulating materials for the electronics industry.

Cross-linked polyethylene English XLPE is an important skill for improving PE function. 

The PE modified by cross-linking can greatly improve its function, and not only significantly improve the mechanical functions of PE, environmental stress cracking, chemical corrosion resistance, creep resistance, electrical functions, etc.

And the temperature resistance grade has been significantly improved, and the heat resistance temperature of PE has been improved from 70 ° C to above 90 ° C, and then the use range of PE has been greatly expanded. 

Today, cross-linked polyethylene (XLPE) is widely used in pipes, films, cable materials, and finished foam products.