Types of Cables

Electrical power cable refers to the cable that we use for transmitting and distributing electrical power. When overhead lines are not possible, authorities transmit the high voltage currents through these cables.

The main components of a power cable are the conductor, the dielectric, and the sheath. In a cable, the conductor is responsible for carrying the current. Insulations or dielectrics protect the live conductor from other objects in an electrical circuit and withstand the service voltage. Sheaths prevent moisture from entering the cable and protect it from external influences, including chemicals, electrochemical attacks, and fire.

Typical cable components

For a cable to function, it should have three components:

• Conductor: Transmission of electricity occurs through the conductor. Copper and aluminium are the two most frequently used conductors.
• Insulator: The wires are shielded with insulating materials to prevent the conductors from touching each other and causing an unintended current flow. The synthetic polymers help to accomplish the requirement.
• Sheath: The sheath provides yet another layer of protection against chemical reactions of the wires with the environment. Polyvinyl chloride (PVC) is the commonly used substance for the sheath.

Everywhere you go, you'll find cables of different types. This is because each cable serves a different purpose. Moreover, the purposes of different cables differ dramatically. For example, aluminium wires or copper wires make up the electrical cables. These wires include a covering of an insulating material consisting of synthetic polymers.

According to their purpose, we classify cables into the below mentioned five categories:

• Shielded Cables: This type of cable transmits high voltage electricity while being shielded. It consists of 1 or 2 insulated wires covered with a woven braid shield or aluminium foil to optimise signal transmission and eliminate irregularities in power frequency and external interference.
• Optical Fibre Cable: Optical data signals are transmitted over cable from an attached light source to a receiving device through these types of cables. We all know what optical fibre is and how we can use it in a wide range of applications.
• Twisted Paired Cables: It is composed of several copper wires that are twisted together and are colour-coded. A telephone cable often contains this type of wire, and the number of wires indicates how resistant it is to interference.
• Ribbon Cables: Multi-wire systems require multiple insulated wires to run parallel to transmit data simultaneously. They are generally used to connect networking devices, such as the CPU, to the motherboard.
• Coaxial Cables: A braid of metal or metal tape encloses the solid copper conductor or steel conductor coated with copper in these coaxial cables. An insulted protective outer layer completely covers these cables. Audio-video cables of this type find their use in networking applications.

Classification of Cables and Colors

Wires come in different colours to serve different purposes. For example, the colours of DC circuit wires are as follows:

• The red wires indicate a positive current.
• Black wires carry the negative current.
• Wires that are white or grey are ground wires.

AC circuits (120, 208, 240 Volts),

• A black line indicates that Phase 1 lines are present. These wires are for power generation.
• The wires in red are phase 2 or transmission wires.
• Phase 3 or power distribution cables are blue in colour.
• Wires in white are neutral.
• Ground wires are green with yellow stripes.

Frequently Asked Questions about Types of Cable

Ques: What are the important components of the cables?
The important components of the cable include:
1. Conductor: The metal part that conducts electricity.
2. Insulation: The insulator part is made of synthetic material and prevents the user from electric shocks.
3. Protective layer: The layer is also known as a sheath. It prevents the breakdown of the wire due to fire or chemicals.

Ques: Why are cables classified as underground cables and overhead lines?
The overhead lines are common for transmission using poles to suspend them in the air, and these are braided metal wires with no protection. On the other hand, the cables are known as underground cables because they are buried deep in the ground and transmit current. The protective covering and the insulation of underground cables prevent the leakage of current and damage to other entities due to the current in the cables.