The outermost layer of wires and cables is typically a rubber or rubber composite sheath. This layer serves not only as insulation but also as protection from damage.
Cables are categorized as either high-voltage or low-voltage. High-voltage cables also have a layer of resin-like filler inside, which acts as insulation. In high-voltage cables, this layer is the most important insulation component. Low-voltage cables lack this layer. Furthermore, a ribbon-like material is wrapped around the cable core to secure each core and fill any gaps.
As for the shielding layer, there are two main functions. The shielding layer in power cables serves the following purposes:
1. Because power cables carry high currents, a magnetic field is generated around the current. To prevent it from affecting other components, the shielding layer is added to contain this electromagnetic field within the cable.
2. It provides a certain degree of grounding protection. If a cable core is damaged, the leaking current can flow through the shielding layer to the grounding grid, providing safety protection.
If it is a control cable, there is no difference in other aspects, but in many places, especially the control cable of the computer system, the shielding layer here is used to shield external influences, because the current itself is very weak and it is very afraid of the influence of external electromagnetic fields.
