When there is alternating current or alternating electromagnetic field in the conductor, the current inside the conductor is unevenly distributed, and the current is concentrated in the "skin" part of the conductor, that is, the current is concentrated in the thin layer on the outer surface of the conductor. The closer it is to the surface of the conductor, the greater the current density, and the actual current inside the conductor is smaller. As a result, the resistance of the conductor increases and its loss power increases. This phenomenon is called skin effect. When the single core cable is in AC or alternating electromagnetic field, the skin effect is obvious and the line loss increases.
Advantages of multi-core cable
Multi core cable refers to the cable with more than one insulated core, which reduces the skin effect of the cable and reduces the loss of the line