As explained in earlier editions of this series, electricity occurs as a result of electrons flowing in a particular direction. Electrons can however not travel through all mediums. Some media or materials permit the movement of electrons and so they are called Conductors, while some materials do not allow the free movement of electrons and so they are called Insulators. Examples of conductors are basically all metals and human beings, while examples of insulators are dry wood, bricks, ceramics, glasses, plastics and so on.
For the records, there are materials that permit the movement of electrons in certain direction when acted upon by external influence and they all called Semi-conductors. Examples of this are silicon, germanium and so on, which are commonly used in making transistors, ICs and many of the active devices found in modern electronics, as they are very effective in manipulating the flow of electricity.
The common name for conductors in our clime is Wire or Cable.
There are different types of cables depending on applications; for example we have; applications: electronics, automotive, industrial, Types: naked, non-sheeted, armored and so on cables.
The purpose of this part 5 of the ELECTRICITY MADE SIMPLE series is to discuss cables used at homes and businesses, to enable readers make informed choices, when selecting/purchasing cables to use for their building projects so as to prevent loss/damage of life/materials from fire, shock and other unwarranted incidences, which may occur from using wrong/fake cables. You should be able to identify the correct/original Nigerian cables that meet the NIS specification, once you complete this series with us.
As stated above, all metals are good conductors; so Bronze, Gold, Brass, Silver, Aluminum and Copper can be used as conductors/cables depending on the application. For example, Gold is used on Circuit board wiring in some specialized and expensive equipment.
Copper and Aluminum are the most commonly used materials for cabling of buildings worldwide; across a variety of applications are.
Copper is more widely used, because original copper has superior current carrying capacity; far better than most other materials. For example, for the same cross-sectional area and length, copper conducts 4 times more electricity than aluminum. Copper is strong, rugged, requires less insulation and does not stretch easily when passed through difficult conditions such as ducts, pipes and so on. Also copper dissipates heat 60% better than aluminum. Overall, it is relatively cheaper than most other alternatives to install for long term applications.
Aluminum is however used for some applications where weight (It weighs 50% less than copper) and cost is very important such as on overhead transmission lines because copper is much heavier and about 3 times costlier than aluminum. For example, as at the time of writing this piece, copper cost $2.73 per pound (453.59 grams) while aluminum cost $0.85 per pound (453.59 grams) at the international market.
Some researchers are even suggesting aluminum for building wiring to save 40-60% on cable cost. This writer is not recommending that.
- There are many forms of cables we shall not touch in this discuss, such as Co-axial and UTP cables for video and data transmission respectively.
- Whereas glass is mentioned above as an insulator, it should be noted that it can be used to conduct electricity by some special arrangement, as it is applied in fiber optic cables.
We may come to that later.
NEXT: We shall discuss common wires used in building wiring and later, the truth about originality of “Nigerian Cables”.
©Tunde Y. Salihu, 2017
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