Solution:

When a defective appliance’s live wire comes into direct touch with its metallic cover for some reason. Then, the appliance gains the live wire’s high potential. Because current passes through his body to the soil, a person contacting the appliance will receive a lethal shock. However, if the appliance is properly earthed, a large current travels to the earth through the device’s case as soon as the live wire makes contact with the metallic case. A fuse in the circuit of the appliance blows out. As a result, the device is disconnected from the power source.