(a) The main function of earth wire is to absorb excess electricity passing through the appliance and to prevent overloading of live wire. The metallic appliances are earthed because whenever there is leakage of current, the leaked current passes through the earth wire to earth.
(b) Short Circuit – When live wire comes in contact with Neutral wire then the resistance becomes zero and with Ohm's law current becomes infinite.
Overloading – When a large number of home appliances are connected simultaneously to same socket and they withdraw large amount of current than mentioned on the switch.
(c) Fuse wire is a safety measurement used in case of overloading, short-circuiting or high voltage from the electricity board.
i. The usual capacity of the fuse wire in the line to feed lights and fans is around 15-20 A or less.
ii. The usual capacity of the fuse wire in the line to feed appliances of 2 kW or more power is a minimum of 30 A but it is preferred to have 50-60 A or less.
