Industrial Wiring Practice Set 3

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Which rated voltage megger is used to measure the insulation resistance value of 3phase 415V induction motor?

  

    (A) 250V

    (B) 500V

    (C) 1000V

    (D) 2500V

1000V

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Which instrument is used to measure the insulation resistance?

  

    (A) Shunt type ohmmeter

    (B) Series type ohmmeter

    (C) Megger

    (D) Multimeter

Megger

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What is the main reason for leakage current flowing in wring installation?

  

    (A) Insulation failure

    (B) Low earth resistance

    (C) Incorrect size of earth wire

    (D) High earth reactance

Insulation failure

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How many earth continuity conductors should be provided from the machine to panel board and to the main earth electrode?

  

    (A) 4

    (B) 3

    (C) 2

    (D) 1

2

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Which size of GI conductor is used for earthing to the motor from the main electrode?

  

    (A) 14 SWG

    (B) 10 SWG

    (C) 8 SWG

    (D) 4 SWG

8 SWG

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