Types of Cables

Electrical cables are shielded conducting wires, used in the generation, transmission, and distribution of electrical power. Electrical cables, in a circuit, are joined through connectors. A combination of cables and connectors is known as a cable assembly. Generally, a cable has three components: conductor, insulator, and sheath. The conducting wire in a cable carries electricity whereas the insulator and the sheath give protection to the cables from unintended circuit paths and chemical reactions. Cables can be classified into various categories, depending on their different uses and structures. Some types are coaxial cables, twisted pairs, optical fibers, patch cables, power cables, data cables, etc. 


Components of a Cable

A cable should have the following three components,

  • Conductor: The conducting part is used to transmit electricity. Extensively used conductors are copper and aluminum. 

  • Insulator: To keep the conductors separated from each other and prevent unintended paths for current flow (e.g. short circuit), the wires are shielded with insulating materials. Various synthetic polymers are used for this purpose.

  • Sheath: It is yet another layer to give protection to the wires from chemical reactions with the atmosphere. A common material for the sheath is PVC (polyvinyl chloride).


Classification of Cables and Colors

Different colors of wires are used for different purposes. In DC circuits, the colors are,

  • Red: Wires for positive current.

  • Black: Wires for negative current. 

  • White or Grey: Ground wires.

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For AC circuits (power 120/208/240 Volts),

  • Black: Phase 1 lines are colored black. These wires are for power generation.

  • Red: Phase 2 or transmission wires.

  • Blue: Phase 3 or power distribution wires.

  • White: Neutral wires.

  • Green or Green with Yellow Stripes: Ground wires.

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Various Types of Electrical Cables and Their Uses

  • Network cables: Network cables are used to connect different components in a networking system. Based on the size and structure of the systems, different types of network cables are used. These are listed below,

  • Coaxial Cables: These cables (also called coax) consist of a conducting core, surrounded by another conducting layer. Both the layers are separated by a dielectric or insulator in the form of a coaxial cylinder. The entire setup is given an outer jacket for protection. Coaxial cables are used to transmit high-frequency signals with minimal energy loss in several devices like televisions, radio transmitters, antennas and many more.

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  • Twisted Pairs: Two cables are twisted together and color-coded. As compared to a pair of untwisted cables, the twisted one has less possibility of crosstalk or interference. These cables are used in ethernet networking systems.

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  • Optical Fibers: Fibers have glass cores surrounded by some protective layers. These cables use total internal reflection to transmit light and therefore have almost zero energy dissipation. Optical fiber has a core inside a cladding. The cladding is optically rarer than the core. The transmitting electromagnetic wave reflects in the core-cladding interface several times. Optical fibers can be classified further in two types, which are multi-mode fiber (short-range) and single-mode fiber (long-range).

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  • Patch Cable: Patch cables are used to connect or “patch” different devices.

  • Internet Cables: Types of internet cables are ethernet cables (shielded and twisted). Ethernet cables connect a computer or a game console to a modem. These cables transfer data across the internet. Some cables, called “cross-over cables” can connect two devices. 

  • Power Cables: Power cable assemblies are used to transmit electrical power. These can be used as permanent wiring in buildings. Power cable types are power cord, extension cable, twisted, shielded, extensible, communication cable, and many more. These cables can be used overhead or buried underground.

  • Types of Computer Cables: Types of computer cables are power cable and data cable. Power cords are used in the charging of a computer or a laptop. Data cables can be of DVI, VGA, or HDMI types. Data cables are used to transfer multimedia from one device to another. 


Did You Know?

  • Copper is used as conducting wires in electrical cables because copper is a good conductor and also cheap. 

  • Cable sheaths protect and hold the conductors from chemical reactions. 

  • Most cables have multiple insulating layers and sheaths. 

  • Polyvinyl chloride, butyl rubber, polyethylene, impregnated paper, etc. compounds are used as the insulating layers in different cables.

  • Multi-mode optical fibers can transmit signals of multiple wavelengths and are used for short-distance transmissions. Single-mode fibers are used for the transmission of a particular frequency.

  • Different kinds of glass were used as the core of the optical fiber. Nowadays, transparent plastics are used in the core. 

  • Power cables come in various sizes depending on the purpose of use.

  • Twisted pairs have reduced energy dissipation and less interference.

FAQ (Frequently Asked Questions)

1) What are Electric Cables Made up of?

Broadly cables are constituted by a conductor, one or multiple insulating layers, and single or multiple sheath layers. The conducting wire in a cable carries electricity whereas the insulator and the sheath give protection to the cables from unintended circuit paths and chemical reactions. Optical fibers are made up of a transparent core, a rarer cladding, and multiple protective layers (jacket).

2) What are the Types of Cables and Which one is Used Where?

Electric cables can be classified into various categories, depending on their different uses and structures. In networking systems, ethernet cables, coaxial, twisted pairs, optical fibers are used for the transmission of signals. Power cords and extension cords are used for televisions, computers, laptops, and game consoles. Data cables are used for the transfer of multimedia from one device to another.