The three conductors of the 3-core cable at far end are shorted and earthed. Afterwards the electrician measures resistance between each conductor and earth using megger. The Electrician is trying to identify:
- Earth fault
- Open circuit fault
- Short circuit fault
- Insufficient data
Correct answer: 2. Open circuit fault
Explanation: Open circuit fault is defined as the fault in which there is a break in the conductor of a cable.
In present scenerio, the electrician is trying to find open circuit fault.
The open-circuit fault can be checked by a megger.
In order to do this, the three conductors of the 3-core cable at the far end are shorted and earthed. Then resistance between each conductor and earth is measured by a megger. The megger will indicate zero resistance in the circuit of the conductor that is not broken. However, if the conductor is broken, the megger will indicate infinite resistance in its circuit.