INTRODUCTION : You have studied about the hazards of electricity in Unit 11 of Block 3. You have learnt that most of the electrical accidents like shock, fire, etc. occur often due to the neglect of fundamentals of electricity. The cause may be as simple as an improper wiring, a wrong choice of the fuse or wire (over- or underrated), or a problem with the earthling of the equipment. You have learnt about the theoretical basis of these functional aspects of electricity. You would have appreciated that through proper electrical maintenance /safe conduct, the mishaps due to electrical equipment can be minimised.
In this exercise are intending to provide you with some practical experience in electrical maintenance. You will do activities like, calculating the amount of current drawn by given appliance/instrument/equipment, suggesting proper procedures for wiring a plug, constructing a continuity testing device and using it to check the ear thing of an appliance.
This will enable you to observe general precautions in the laboratory and undertake (if required) preliminary steps like, checking the wire / fuse / earthing of an appliance, if it is not working properly. It is like giving 2 first aid till the doctor (electrician in the present case) comes. We do not intend to make electricians out of you.