earthing or grounding Mcqs
1. Average resistance of human body is____________?
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A. 2000 ohms

B. 1000 ohms

C. 500 ohms

D. 1500 ohms

2. When earth fault occurs______________?
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A. none of the above

B. voltage potential at the earth mat remains zero irrespective of fault

C. voltage potential at the earth mat increases due to grounding

D. voltage potential at the earth mat decreases due to grounding

3. The size of the earth or ground wire is based on the______________?
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A. maximum fault current carrying through the ground wire

B. rated current carrying capacity of the service line

C. depends on the soil resistance

D. both (A) and (C)
4. For an EHV equipment for maintenance first it should be isolated and connected to ground because_____________?
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A. to provide low impedance

B. to discharge the charging capacitance to ground

C. protection for operating personnel

D. both (B) and (C)
5. When the 3-phase system is not grounded and if Single Line to Ground fault occurs, the voltage of the other two healthy phases will____________?
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A. Remains unaffected

B. Increases

C. Decreases

6. Moisture content in the soil __________ the earth soil resistance?
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A. decrease

B. does not affect

C. none of the above

D. increase

7. Ground resistance should be designed such that_____________?
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A. grounding resistance should be always zero

B. grounding resistance should be as high as possible

C. none of the above

D. grounding resistance should be as low as possible
8. Factors on which soil resistance depends_______________?
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A. moisture

B. depth of the electrode

C. all the above

D. Nacl

9. The objective of earthing or grounding is_______________?
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A. none of the above

B. to provide as low resistance possible to the ground

C. to provide as high resistance possible to the ground

D. to provide flow of positive, negative and zero sequence currents

10. Generally grounding is provided for
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A. only for the safety of the equipment

B. only for the safety of the operating personnel

C. both (A) and (B)

D. none of the above