State the significance of the following devices in domestic circuits :
(i) Main switch (ii) Main fuse (iii) Electricity meter

Explanation

i] In case of any mishaps such as accidental fire, electric shock, etc., or when some electrical work is being done at home, main switch can be switched off to cut off electricity supply to all appliances. This prevents further damage and avoids the possibility of electric shock.
ii] If a high current flows due to lightning, sudden increase in supply voltage, short circuit, overloading, faulty appliance, etc., the main fuse burns off and cuts the electricity supply to the home . This protects all the appliances and line wires from getting burnt or damaged.
iii] Electricity meter is installed in every home to measure the amount of electrical energy consumed. Its main purpose is to help the electricity - supply board in billing.