Question

The diagram shows a three pin socket marked as 1,2 and 3.

A) Identify and write live (L), neutral (N) and earth (E) against the correct number.
B) To which part of the appliance is terminal 1 connected?
C) To which wire joined to 2 or 3, is the fuse connected and why?

Answer 1

Hint: Recall that there are three wires used to complete a circuit. The live wire is red in colour, the neutral wire is blue and the Earth wire is either green or yellow in colour. The live wire is also called the phase wire. The main fuse is connected to the live wire. The neutral wire completes the circuit. The main switch is connected to live and neutral wires.

Complete solution:
Terminal $1$ is connected to the Earth wire
Terminal $2$ is connected to the neutral wire
Terminal $3$ is connected to the live wire
The terminal 1 is connected to the outer metallic case of the appliance.
The fuse wire is connected to the live wire that is joined to the terminal 3. This is done so that if there is excessive flow of current in the circuit, then the fuse wire melts first and breaks down in order to protect the electrical appliances from damage.

Note: It is important to remember that when there is excessive current flowing in the circuit, ten the fuse wire melts due to the heating effect of electric current. The fuse wire has a low melting point. Therefore, when excess current flows, the fuse wire melts. It is important to choose proper fuse wire. If the fuse wire chosen is underrated then it will not be able to protect the circuit. On the other hand If the fuse wire chosen is overrated then it will not break the circuit when required.