Why there are so many layers in power cable?
High voltage power cables with a layer of resin-like filler which mainly play the role of insulation, low voltage power cables without this stuff. Power cables are with some similar ribbons wrapped around, which are to secure the each cable core, filled the middle of the gap.
Shield layer, there are two cases, the power cable shield has two effects: first, because the current through the power cable is relatively large, the current creates a magnetic field around, in order not to affect other elements, so add that to shield electromagnetic fields shield in the cable; the second is to play a role ground protection, if damaged, leaked current can occur within the cable core role shield along the outflow, played security protection.
Power cable is made of a conductive core, an insulating layer, a protective layer. Detailed: conductive core, an inner semiconducting layer, an insulating layer and an outer semiconductive layer, copper shield, filler, inner liner, double steel protective layer, the outer sheath. Above the main structure is for 10kV power cable.