Basic Electricity 2, WASSCE (PC), 2017

Question 7

 

  1. The metal part of an electric kettle gives an electric shock when touched. State two

    1. Possible causes of the problem;
    2. Steps that should be taken in diagnosing fault;
    3. Instruments that can be used for diagnosing the fault.

Observation

 

(a)       -           Live conductor touching the frame of the kettle
-           Poor or improper earthing.                                                             
 (b)      -           Switch off the appliance
            -           Unplug it from the supply
            -           Test for earth continuity.
(c)       -           Insulation resistance tester (megger tester)
            -           Ohmeter.
            -           Multimeter (ohm range).
                                                                    
Many candidates who attempted this question did not do well.