What is the reason for megging a cable?

What is the reason for megging a cable?

• A. To measure cable resistance
• B. To tag and identify cable (good ground, tap wire 3 times)
• C. To test continuity
• D. To identify polarity

Answer: (B)

Megging a cable is about using insulation-resistance testing to verify that the cable’s insulation is sound and, in practice, to help identify a specific conductor among several in a bundle. The megger applies a high voltage and measures leakage current to ground; when insulation is good, the resistance reads very high. Technicians use this property to tag and identify a particular cable: connect the megger between the conductor and a known ground, then lightly tap the wire (three quick taps) so the tester’s indication helps you confirm exactly which lead you’re testing. Once identified, you can tag the cable for future work. This task is distinct from measuring DC resistance, testing continuity, or checking polarity, which use different methods.

Megging a cable is about using insulation-resistance testing to verify that the cable’s insulation is sound and, in practice, to help identify a specific conductor among several in a bundle. The megger applies a high voltage and measures leakage current to ground; when insulation is good, the resistance reads very high. Technicians use this property to tag and identify a particular cable: connect the megger between the conductor and a known ground, then lightly tap the wire (three quick taps) so the tester’s indication helps you confirm exactly which lead you’re testing. Once identified, you can tag the cable for future work. This task is distinct from measuring DC resistance, testing continuity, or checking polarity, which use different methods.