Question

In our houses we receive A.C. electric power of 220 V. In electric iron or electric heater cables having three wires with insulation of three different colours – red, black and green are used to draw current from the mains. What are these three different wires called? Name them colourwise. What is the potential difference between the red wire and the black wire? What is the role of the wire with green insulation in case of accidental leakage of electric current to the metallic body of an electrical appliance?

Hint:

The earth wire (green) is essential for safety in electrical circuits to prevent electric shocks by directing leakage currents to the ground.

Answer 1

(i) An electric circuit typically uses three insulated wires of different colors:
Red wire: Live (or Phase) wire – delivers current from the power source.
Black wire: Neutral wire – completes the circuit, providing a return path for current.
Green wire: Earth wire – a safety path allowing current to flow to the ground in case of a fault or leakage.
(ii) The potential difference between the red (live) and black (neutral) wires is usually \( 220V \) in standard household power systems.
(iii) The green (earth) wire offers a safe route for electrical current to the ground if current leaks to the metal casing of an appliance.
This prevents electric shock by directing the current away from the user.