Earthing
1. The code of practice for earthing is governed by
- IS: 3043
- IS: 4340
- IS: 4340
- IS: 4430
a. IS: 3043
2. The length of pipe electrode used for earthing should not be less than
- 3.5 m
- 4 m
- 4.5 m
- 5 m
b. 4 m
3. As per IS, the earthing electrode shall not be within a distance of ______ mtrs from any building being earthed.
- 0.5 m
- 1 m
- 1.5 m
- 2 m
c. 1.5 m
4. Maximum permissible earth resistance at large power stations is
- 0.5 ohm
- 1 ohm
- 2 ohms
- 8 ohms
a. 0.5 ohm
5. Maximum permissible earth resistance at major power stations is
- 0.5 ohm
- 1 ohm
- 2 ohms
- 8 ohms
b. 1 ohm
6. Maximum permissible earth resistance at small power stations is
- 0.5 ohm
- 1 ohm
- 2 ohms
- 8 ohms
c. 2 ohms
7. Maximum permissible earth resistance for buildings is
- 0.5 ohm
- 1 ohm
- 2 ohms
- 8 ohms
d. 8 ohms
8. Earth continuity inside an installation i.e. from plate earth to any point in installation should be
- 0.5 ohm
- 1 ohm
- 2 ohms
- 8 ohms
b. 1 ohm
9. The plate electrode of copper used for earthing should be with minimum size of
- 50cm x 50cm x 3.15mm
- 50cm x 50cm x 6.3mm
- 60cm x 60cm x 3.15mm
- 60cm x 60cm x 6.3mm
c. 60cm x 60cm x 3.15mm
10. The plate electrode of GI or steel used for earthing should be with minimum size of
- 50cm x 50cm x 3.15mm
- 50cm x 50cm x 6.3mm
- 60cm x 60cm x 3.15mm
- 60cm x 60cm x 6.3mm
d. 60cm x 60cm x 6.3mm
11. In pipe earthing the minimum internal diameter for GI pipe should be
- 30 mm
- 40 mm
- 50 mm
- 60 mm
b. 40 mm
12. In pipe earthing the minimum internal diameter for cast iron pipe should be
- 80 mm
- 90 mm
- 100 mm
- 60 mm
c. 100 mm
13. Copper strip electrodes used for earthing should not be less than
- 22.5 mm x 1.60 mm
- 20 mm x 2.5 mm
- 25 x 1.60 mm
- 25 mm x 2.5 mm
c. 25 x 1.60 mm
14. GI or Steel strip electrodes used for earthing should not be less than
- 25 mm x 4mm
- 20 mm x 3 mm
- 25mm x 3mm
- 20mm x 4mm
a. 25 mm x 4mm
15. Earthing arrangement for HT installations, substations and generating stations should be inspected at an interval of
- 3 months
- 6 months
- 9 months
- 12 months
d. 12 months
16. Earthing arrangement for low voltage installations such as service builsings, public buildings should be inspected at an interval of
- 3 months
- 6 months
- 9 months
- 12 months
b. 6 months
17. Earthing arrangement for residential buildings should be inspected at an interval of
- 3 months
- 6 months
- 9 months
- 12 months
b. 6 months
18. Earthing arrangement for medium voltage installations should be inspected at an interval of
- 3 months
- 6 months
- 9 months
- 12 months
d. 12 months
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