[Physics Class Notes] on Types of Cables Pdf for Exam

An Eclectic cable is a cable used to distribute and transmit electrical power. The Electric Cable is used to transmit high voltage where overhead lines are impractical to use.

An electric cable is made of three kinds of things those are –  

• Conductor

• Dielectric

• Sheath

The conductor provides the conducting path in the Electric Cable. The insulation or dielectric withstands the service voltage and isolates the live conductor with another subject.

The sheath protects the Cable from all external influences like chemical and fire attacks. Also, it prevents moisture from harming the electric Cable.

Introduction

Electric cables are usually made of copper Because electricity moves well in copper. Copper is not as expensive as silver, making the work easier. Sometimes aluminum is used in cable making because it is cheaper than copper. A cable is made when many wires come together.

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. 

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 the negative current. 

• White or Grey: Ground wires.

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.

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.  

• 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. 

• 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 into two types, which are multi-mode fiber (short-range) and single-mode fiber (long-range).    

• 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 the 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 cables and data cables. 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.

Ribbon Electric Cables

Ribbon Electric Cable is made of multiple insulated wires running parallel with one another. It is used for the transmission of multiple data simultaneously.  For example, it says that the CPU with the motherboard is connected by the Cable and is generally used for networking devices’ interconnection.

Shielded Cables

Shielded Cable is made of 1 or 2 insulated wires covered by a woven braided shield or aluminum Mylar foil for better signal transmission and removing irregularities in radio frequency of power and external interference. These cables transmit high voltage electric current. A shield is protecting it.

Twisted Pair Cables has two or more insulated
copper wires twisted with each other and coded with color. Twisted Pair cables are especially used in telephone cables. The number of wires can measure the resistance to external interference.

Coaxial Cables are made of solid copper or steel conductor plated with copper.  The plated part is enclosed in the metallic braid and metallic tape. This entire Cable is covered with an insulated protective outer jacket.  In computer networking and audio-video networking, this kind of Cable is used.

Fibre Optics Cable transports optical data signals to the receiving device from an attached light source.  One must be pretty much aware of optical fiber and its uses in a wide variety of applications.

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.

• Thomas Edison invented the electric Cable.