In our homes, we receive the supply of electric power through a main supply also called mains, either supported through overhead electric poles or by underground cables. In our country the potential difference between the two wires (live wire and neutral wire) of this supply is $220\ V$. (a) Write the colours of the insulation covers of the line wires through which supply comes to our homes. [1] (b) What should be the current rating of the electric circuit ($220\ V$) so that an electric iron of $1\ kW$ power rating can be operated? [1] (c) (i) What is the function of the earth wire? State the advantage of the earth wire in domestic electric appliances such as electric iron. [2] OR (c) (ii) List two precautions to be taken to avoid electrical accidents. State how these precautions prevent possible damage to the circuit/appliance. [2]

(a) The colours of the insulation covers of the line wires through which supply comes to our homes are red, yellow and blue. Red is the live wire, yellow is the neutral wire and blue is the earth wire.<hr/>(b) The current rating of the electric circuit should be $\frac{1000}{220} = 4.55 A$.<hr/>(c) (i) The function of the earth wire is to provide a safe path to the electric current to flow to the ground in case of any fault in the circuit. The advantage of the earth wire in domestic electric appliances such as electric iron is that it prevents the user from getting electric shock.<hr/>(c) (ii) Two precautions to be taken to avoid electrical accidents are: (1) Use of earth wire in domestic electric appliances. (2) Use of fuse in electric circuit. These precautions prevent possible damage to the circuit/appliance by providing a safe path to the electric current to flow to the ground in case of any fault in the circuit and by breaking the circuit in case of excessive current flow respectively.