Generally, The Structure of Cable is as Follows: 

The first layer: outer skin, which is generally made of PVC or PU

Second Layer: wire shielding

Third layer: outer skin of core wire

Fourth layer: copper wire

For your cable requirement, could you PLS tell us the cable material, color, AWG?
If client could supply the drawing, it is helpful to check quickly, or tell us your customization, our professional engineer team could support you.