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

State the significance of the following devices in domestic circuits :

1.	State the significance of the following devices in domestic circuits : (i) Main switch(ii) Main fuse(iii) Electricity meter
Answer» Solution :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 electricitysupply to all appliances. Thisprevents furtherdamage and avoids the possibilityof electric shock. II] If a high current flows due to lightning, suddenincrease in supply voltage, short circuit,overloading, faulty appliance, etc., the main FUSE burns off and cuts the electricitysupplyto the home . This protects all the appliances and linewires fromgetting burnt or damaged. iii] Electricity meter is INSTALLED in every home to measure the AMOUNT of electrical energyconsumed. Its main purpose is to help the electricity- supply board in BILLING.