The outer layer of Cat5e & Cat6 cable is generally HDPE, which is used for insulation and also protects the cable from damage.
The cable is divided into high voltage and low voltage cable. If it is high voltage, there will be a layer of resin-like filler inside, which is used for insulation. In high voltage cable, this layer is the most important part of insulation. The low-voltage cable does not have this layer of material. Then there will be some cotton-filler material inside, which is to fix each core of the cable and fill the gap in the middle.
As for the shield layer, there are two cases, the functions of the power cable shielding layer as below:
1、Because the current through the power cable is relatively large, a magnetic field is generated around the current. In order not to affect other components, the shielding layer can shield the electromagnetic field in the cable.
2、It can play a certain role in grounding protection. If the cable core is damaged, the leaked current can flow into the grounding net along the shielding layer, which plays a role in safety protection.
If it is a control cable, there is no difference. It is only in many places, especially the control cable of the computer system. The shielding layer here is used to shield the external influence, because its current is very weak, and it is very afraid of the influence of external electromagnetic fields.