Why use wire and cable shielding
is the use of metal mesh braid layer to wrap the signal transmission line. Braid is generally copper or tinned copper. Shielding is to ensure the transmission performance of the system under electromagnetic interference. The anti-interference here should include two aspects, that is, the ability to resist external electromagnetic interference and the system itself to radiate electromagnetic interference.
The outermost wire and cable are generally rubber or rubber synthetic sleeve, the role of this layer is insulated, but also play a role in protecting the cable from harm.
The cable is sub-high voltage or low voltage cable, if it is high pressure, there will be a layer of resin-like filler, which is insulated, in high-voltage cable, this layer is the most important part of the insulation. There is no such thing in the low pressure, and then there will be some ribbon-like things, which are used to fix each core of the cable and fill the gap in the middle.
As for the shield, divided into two cases, the role of the shield of the power cable
1, because the current through the power cable is relatively large, the current will produce a magnetic field around, in order not to affect other components, so the shield can shield this electromagnetic field in the cable.
2, can play a certain role in grounding protection, if the cable core damage occurs, the leakage current can be shielded shielding layer such as the ground network, play a role in security.
In the case of control cables, there is no difference except in many places, especially in the control of computer systems. Shielding is used to shield external influences because of their weak current and the fear of external electromagnetic fields.