Page 106 - Electrician - TT (Volume 1)

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