Regulations for single core cables

Cables with voltage levels of 35kV and below are grounded at both ends. This is because most of these cables are three-core cables. In normal operation, the sum of the current flowing through the three cores is zero. There is basically no magnetic link outside, so there is basically no induced voltage at both ends of the aluminum package or metal shielding layer, so no induced current will flow through the aluminum package or metal shielding layer after both ends are grounded.
Power cables are generally composed of wires, insulation layers and protective layers, including single-core, double-core and three-core cables.

Single-core means that there is only one conductor in an insulating layer. If it is used in a single-phase lighting circuit, it needs to be laid in parallel with two conductors. Double-core means that there are two conductors in an insulating layer, if it is to be used in a single-phase lighting circuit, only one is used for laying. (Wires are divided into multiple strands and single strands, as well as soft cores and hard cores. The selection is based on the conditions of use and the power used)