Question

According to the international convention of colour coding in a wire
(A) Live is red, neutral is yellow and earth is green
(B) Live is red, neutral is green and earth is black
(C) Live is brown, neutral is blue and earth is black
(D) Live is red, neutral is black and earth is green

Answer 1

The concept of ‘colour conventions’ refers to the idea that certain colours are familiarly associated with specific meanings. Therefore the developers of systems in which colour electronic displays will be used for the man-machine interface should pay attention to colour conventions.

Complete step by step answer:
To answer this question let us first understand the meanings of a live wire, neutral wire and earth wire. The electricity that is supplied from the power station to our homes, shops, hospitals, factories, etc. is transported very efficiently from a long distance with minimum loss of electrical energy. This supplied electricity is referred to as mains electricity and is only supplied is ac. In our homes when this mains supply is connected to our appliances using a plug, the wires inside the plug are divided into a live wire, neutral wire, earth wire, and two other wires that complete the circuit by connecting it to the household appliances.
The live wire helps to supply the current from the plug to the appliance to be used. Live wires are also termed as the hot wire. They are the only wire that contains electricity.
The neutral wire helps to carry the current back from the appliance to the plug completing an entire circuit and they consist of zero potential.
In rare cases, if the live wire comes in contact with a metal coating of an appliance, a huge amount of wire is expected to flow through the metal damaging the appliance in the process or possibly electrocuting us in case we are in contact with the metal appliance. To prevent this earth wire is installed so that the current will pass to the earth and thus saving us.
Hence, according to the international colour coding convention, it is stated that live wire is represented with red colour, the neutral wire is represented as black colour and the earth wire is represented as green or yellow colour.
Hence, option (D) is the correct answer.

Note:
The above answer is stated according to the old international colour convention of wires. According to the new international convention of wires live wire is represented with brown colour, the neutral wire is represented as blue colour and the earth wire is represented as green or yellow colour.