The electrical cable. Definition and composition.

An electrical cable is a conductor or set of them coated by an insulating or protective material, used to transport electrical energy, generally.

The best conductor of electricity is silver. However, due to its high price, it is usually used copper or aluminum. The latter, although it has an electrical conductivity of 60% compared to copper, is more economical and lightweight. So, it is ideal for overhead transmission lines for electricity in high voltage networks.

These metals together with others such as gold, iron and alloys are optimal to conduct electricity. Although gold is worse conductive than copper, it is often used in battery terminals and electrical connectors because of its durability and corrosion resistance.

In addition, there are other materials that are also good conductors such as graphite, solutions and saline solutions (seawater, for example) or any material in plasma state.


Composition of the electric cable

A cable contains the following elements:

  • Conductor: It moves the electric current. It may be of different metallic materials and be formed by one or more threads.
  • Insulation: It covers the conductor to prevent electric current flow outside it.
  • Fill layer: Insulating material that surrounds the conductors to keep the whole circular section.
  • Cover, jacket: External mechanical protection of the conductor against the action of temperature, sun, rain, etc, made of polymeric material, generally.
  • Protection: In some cases the cable may carry a screen, a metal shield that isolates the signals passing through inside the cable, from external interference. Or an armor, a mechanical protection which protects it from a possible external aggression.

In a next post we will discuss the types of electrical cables. Is there anything you want to add as to the basic definition and / or composition of an electric cable?