Do you know how water gets to the faucets on your kitchen sink?
It comes through pipes.
Pipes let water flow in the direction we want it to go.
How do we make electricity flow in the direction we want it to go?
The electrical energy we call “electricity” is made in huge power stations.
What connects the electric sockets in your home with the power station?
The answer is wires.
Wires are the “pipes” of the electricity system.
A wire is a long, thin piece of metal. It may be a single strand of metal, or it may be two or more strands twisted together. Some wires are thick and stiff, and others are thin and bend easily.
Why are electric wires covered?
A material that allows electricity to flow through it is called a conductor. Metals are good conductors. Some metals are better conductors than others. Silver is the best conductor of all, but it is too expensive to use to make wires. Copper is also a very good conductor and much cheaper to use than silver. So most of the wires that we use to conduct electricity are copper wires.
But it’s best not to try to conduct electricity along a bare wire. When a current is flowing through a bare wire, it will also flow through any metal object or other conductor that touches the wire. Even the human body can conduct electricity. If a person standing on the ground touches a bare wire which is connected to a power line, an electric current will flow through the person and into the ground. The person may receive a dangerous electric shock and might even be killed.
We need to make sure that electric current goes just where we want it and nowhere else. So the wires used to carry electricity are covered with materials that are poor conductors of electricity. Rubber and plastic conduct electricity poorly. They are both good insulators. A bare wire that is covered with rubber or plastic is called an insulated wire, or cable.
If cable is used for the circuit wires, there are three wires inside the cable. Two of these wires carry the electric current to and from the fuse box. One is a black, red, or blue wire and the other a white wire. The third wire, which can be bare or green, is called the ground wire. It may be connected to the main water pipe. If there is a fault in the wiring, the ground wire takes the current safely away into the ground.