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How cable is made

 

A traditional cable has three main components.

  • Conductors – a conductor is used to carry the current (the flow of electricity) through the cable. Conductors are made of copper or aluminium and a number of conductors may be required in the one cable (multicore cables). The size of the conductor used reflects the amount of power, or current, the cable is capable of carrying.

  • Insulation – the insulation in a cable is designed to cater for the voltage level of the cable, ie. the higher the voltage of the cable, the thicker the insulation needs to be. All conductors in the one cable are insulated with the same material. The insulation material can be constructed from a wide range of materials, including PVC (Polyvinyl Chloride), PE (Polyethylene), XLPE (Cross-linked polyethylene), EPR (Ethylene Propylene Rubber), CPE (Chlorinated Polyethylene) Paper.

  • Protection – the cable requires protection from the environment in which it is to operate. This can take the form of a metallic shield such as Lead or Steel Wire Armour, or a polymeric such as PVC, HDPE (High Density Polyethylene) or Rubber.

Cable manufacturing these days is a far more automated process than in the past. Below is an outline of the manufacturing process for standard building wire cables.

The process begins with the conductor, which is usually copper. The copper wire will go through a process called drawing, where the copper strands which form the cable are made thinner. The wires are stranded and then taken to extrusion for insulation.

Depending on the cable design being manufactured, the insulated cores are layed-up and than again taken to extrusion for sheathing. Some cables will have additional layers added, such as nylon for termite protection, or armouring for mechanical protection.

The completed cable is tested for electrical performance, and then sent to packaging. In the case of small flat cables they are automatically wound onto spools, palletised and despatched. Larger cables are wound onto drums of varying sizes.

For a diagrammatic explanation of the cable making process, please refer to the attached PDFs.