What are the functions of the heating cable wire shield?

In the current heating cable and all kinds of cables, the shielding layer is a common component, and the way of wire (net) is used to form a barrier. In this issue, Xiao An will understand the important role of the wire shield in the heating cable with you:

The concept of the shield layer: In general, when the shield layer is only connected at one end and suspended at the other end, it can only prevent electrostatic induction, and can not prevent the voltage induced by the change of magnetic field strength. In order to reduce the induced voltage of the shield core wire, a double-layer shield separated by insulation should be used when only one end of the shield layer is equipotential connected, and the outer shield should be equipotential connected at least at both ends. In this case, the outer shield and other equal potential connections form a loop, sensing a current, so that the magnetic flux reduces the strength of the source magnetic field, which essentially cancels out the voltage induced in the absence of the outer shield.

The metal shielding layer is mainly for electromagnetic shielding, so that the internal electromagnetic interference is not subject to external electromagnetic interference, and the internal electromagnetic energy is not easily run outside. It is used more in electrical equipment, and any place or part that needs to resist electromagnetic interference requires metal shielding. In the heating cable, the role of the metal shield layer in the cable is mainly reflected in the following aspects:

Strengthen the role of the limiting electric field in the insulation layer, so that the electric field direction is consistent with the direction of the insulation radius (that is, radial), and the metal shielding belt is grounded. The electric field terminates on the metal band, and there is no longer an electric field outside the metal band.

Prevent axial surface discharge. When the cable is not well grounded, because the semi-conductive layer has a certain resistivity, it may cause uneven potential distribution along the cable axis, resulting in cable surface discharge.

The plant protection system requires outer conductor shielding. The wrapped copper strip has excellent lightning protection characteristics.

Under normal conditions, the capacitor current flows through, and the metal strip can be used as the circuit of the short-circuit fault current in the case of short circuit.

Through the above understanding of the cable shielding layer process, Xiao An here also wants to point out to you that the radiation problem of heating cable electric floor heating, users who do not know the structure of heating cable they will certainly worry about the problem of cable radiation, and may also give up this high-quality heating method. So what we need to know is that after the heating cable is processed by the shielding layer process, the amount of radiation finally generated is no different from the household appliances in our homes (lighting bulbs). Be sure not to go into the misunderstanding that the heating cable radiation is large.