Page 106 - Electrician - TT (Volume 1)
P. 106

ELECTRICIAN - CITS




           TEST-I (procedure)
           •  Rotate the MEGGER handle to send current through circuit
           •  Note down the reading of the meter shown by its needle deflected over the calibrated over the MΩ scale.
           •  The reading of the meter gives directly the insulation resistance b/w conductors and earth.

           •  According to IE Regulations ,the measured value should not be less than 50MΩ/ (no of outlets) or not less than
              1MΩ. (Switch, lamp holder and socket are taken as individual outlet)
           Insulation resistance between conductors


























           AIM: To find the value of insulation resistance between line and neutral conductors and also to locate a short
           circuit if any in the complete installation.
           Steps
           •  Remove the loop provided at the main switch.
           •  All the lamps and metallic connections are removed from holder and plug points.

           •  Rest all thing remains same that is main switch is in OFF position  , main          fuses with drawn , all other fuses
              in their position , all single pole switch in ON position.
           TEST-II (procedure)

           1  Connect the earth terminal ‘E’ of MEGGER to neutral link.
           2  Connect the line terminal ‘L’ of MEGGER to phase point.
           3  Rotate the MEGGER handle to its normal speed.
           4  In this test also the measured value should not be less than 1MΩ.

           5  This is the insulation resistance b/w line and neutral conductors
           6  However if the reading is zero, it means that there is a short circuit in the wiring which should be removed.
           Continuity test(open circuit test)
           This test is carried out to check the continuity of cables in the individual sub circuits
           Steps
           1  S/OFF main switch

           2  Remove all main and distribution circuit fuses
           3  Place all bulbs in position, connect all to respective ceiling roses, regulators and switches, short all sockets out
              lets by linking phase and neutral.





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 CITS : Power - Electrician & Wireman - Lesson 20-25  CITS : Power - Electrician & Wireman - Lesson 20-25
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