Why Copper Is Used to Make Electrical Wires

Copper is one of the most known metals, primarily because it has high electrical and thermal conductivity. Whether it is a power cable, a TV, computer or any kitchen appliance, copper is inevitable. With atomic number 29, copper has one free electron and forms an essential part of our everyday life.

If you have ever touched an iron rod, connected at one end to an electrical supply, you would know that copper is not the only metal that can conduct electricity. Then what makes copper such a versatile metal, especially for electrical wirings?

High conductivity

Every metal to some extent has the ability to conduct electricity. While there are some exceptions with metals (Bismuth does not conduct current), a few non-metals also conduct electricity (example, Graphite).

The high conductivity of copper means it offers lesser resistance to the flow of current. A section of copper can conduct current more easily than any other metal of same size and shape. This means, a cross section with same area and length will more easily conduct electricity when compared to most metals.

Inexpensive

For the properties, copper is relatively inexpensive. Gold, for example, is also a great conductor but costs 40 times as much as copper. So, with the amount of money you will lay 1 meter wire made of gold, you can lay 40 times longer wire with copper.

It is interesting to note that copper, when compared to iron and aluminum, isn’t near as cheap as the two metals but it is cheap for the amount of properties that come along with it.

High Ductility

If you have ever laid wiring or saw an electrician lay one, you would know how easily copper can bend. This is an essential property of copper because not many metals are as ductile as Cu. The high ductility means Cu can be easily drawn into wires of given shape and length without applying too much force. The deformation neither takes off the conductivity nor the inexpensive nature of the metal.

Thermal Resistant

An element with high conductivity generates less heat for the same amount of current compared to an element with low conductivity.

Higher the conductivity, lower is the resistance.

H = i² r t

Thus, copper wire cables produce lesser heat when subjected to potential difference for time ‘t’.

According to ESFI, electrical short circuiting is the number one cause of residential house fires. If wires were made of iron, you would be twice more likely to have your house ablaze. Also, the heat loss would be tremendous, thus translating to a higher energy consumption and bill. Iron is also very brittle in nature, thus would break more while laying.

Copper also handles high voltage well.

Low melting point

The melting point of copper is around 1085°C while that of iron is 1530°C. This means, if there is overheating in the wire, copper would melt much sooner than iron.

When wires melt, the circuit usually breaks and so does the flow of current. Similar is the idea behind a fuse, which is to deliberately create a susceptible, low-tolerance component that could melt if the current (or voltage) exceeds above a threshold. The overall perk of low melting point of Copper is better use hazard and safety compliances.