How the Electrical Power Cable is Constructed and Used?

An electrical power cable is used for the transmission and distribution of electrical energy. Two or more electrical conductors are joined together under a protective sheath. This type of cable is mainly used for the transmission of extra high voltage wires in places where overhead lines are unviable. However, one disadvantage is its higher costs as compared to the aerial cables of the same voltage.

It’s construction process:

The electrical power cable mainly comprises of three components i.e. the conductor, dielectric (insulator), and sheath.

1. The conductor in the cable specifies the conducting path for the current. Copper and aluminum wires are used as a conductor material in cables because of their high electrical conductivity. Power cables are made from several bare copper or aluminum wires.

2. The dielectric or insulation bears the service voltage and segregates the conductor from other objects. The commonly used dielectric in power cables includes polyvinyl chloride cable, polyethylene, impregnated paper, butyl rubber, and cross-linked polyethylene.

3. The sheath controls and prevents the moistures to seep through. It shields the cables from all external influences and disasters. Cable sheath is made up of lead alloy and used as an inner coating of protection. Often, aluminum sheath is used as it is less expensive. Lead sheaths run the risk of being damaged by corrosion and other external influences.

Where are they used:

Electrical power cable is installed as permanent wiring within buildings and huge commercial complexes either buried in the ground or left exposed overhead. They are designed and made as per voltage, current to be supplied, and/ or based on the purpose of its use customized to the needs of the customers. When applied for mining purpose, the cables are built sturdier with double shield (inner and outer layering). When laid underground, the cables are less prone to risks. They are protected from attacks like fire, lightings, and are safe from voltage fluctuations.

Quality tests

The electrical power cable is put through severe tests before they are released to the public.

For aluminum power cables the tests are called as:

a. Tensile tests: These tests are done to reconfirm the durability and strength of the aluminum wires that are to be used as conductors.

b. Wrapping test: This test confirms the flexibility of the wire. How it can be twisted or bonded without breaking or developing cracks.

For copper power cables the tests are classified as:

a. Annealing test: Copper and aluminum wires that are used for welding are subject to this test. It confirms the durability of the conductor and if it can sustain the bending and twisting without cracking and losing its property.

b. Persulphate test: Tinned copper wire is used to perform the tests to determine the properties that copper displays. The tin coat can sometimes cause pinholes on the conductor. The tin coat is applied because it serves as a barrier between the insulation and copper. Otherwise, there are risks of the insulation getting degraded by the catalytic effect of copper. The tinned wire is also used for braiding to enhance the protection to cables and earthing purpose.