Current threads      

What moves across the ceiling, and comes down through each and every wall of your house? No, not spiders or ants but electric wires.

Electric wires are present in our homes, in schools, in offices, in restaurants, in buses, in cars… everywhere! When we use electricity, we use wires. Electric wires are cylindrical, elongated strand of drawn metal that act as conductors in transmission of electric power. That is, they carry electric current.

A power cable is an assembly of two or more electrical wires held together with an overall cover (sheath). The first cables for building wiring were introduced in 1922.

The first power distribution system developed by Thomas Edison used a very distinct type of wire – copper rods, wrapped in jute and placed in rigid pipes filled with a bituminous compound!

At first, electric wires were covered with cloth or simply left bare. They were secured by staples to the framing of the building or on running
boards. And when they went through walls, they were protected with cloth tape. These systems were extremely unsafe, prone to triggering
electrocution and fire.

     Wiring process    

1. Lubricants, such as oil and copper (II) sulfate solution, are applied on the wires.
    
2. Wire is repeatedly drawn through progressively smaller dies (a metal block that is used for forming materials like sheet metal)
   to get the desired diameter.
    
3. The wire is heated to an extremity in an inert atmosphere to soften it, and then cooled in a process called annealing, to prevent oxidation.
    
4. Electrical wires are covered with insulating materials, such as plastic or rubber-like polymers. Stranding or covering machines wind material onto the wire.
    
5. Two or more insulated wires are wrapped and protected with substances like paraffin, preservative compound, bitumen or lead
   sheathing or steel taping.

     Wire-drawing     

Single-block wire-drawing machines have a castiron bench or table with a bracket standing up to hold the Dies in position, and two vertical
drums.

1. One of the vertical drums rotates and pulls the wire through the Die by coiling around its surface.
    
2. The coil of wire is stored upon another drum or ‘Swift’, which lies behind the Die. It reels off the wire as fast as required.

Continuous wire-drawing machines have a series of Dies, and blocks between each Die to coil the wire around one block and lead on to the next Die.

It is very important for the blocks to rotate uniformly and pull the wire in an even manner to prevent the weakening or breaking up of the wire.