Q Bank - Electrical Engineering Part -3. EARTHING

3. EARTHING

1. The code of practice for earthing is governed by

 (a) IS: 3043 (b) IS: 4340 (c) IS: 4340 (d) IS: 4430

2. The length of pipe electrode used for earthing should not be less than

 (a) 3.5 m (b) 4 m (c) 4.5 m (d) 5 m

3. As per IS, the earthing electrode shall not be within a distance of ______ mtrs from

any building being earthed.

 (a) 0.5 m (b) 1 m (c) 1.5 m (d) 2 m

4. Maximum permissible earth resistance at large power stations is

 (a) 0.5 ohm (b) 1 ohm (c) 2 ohms (d) 8 ohms

5. Maximum permissible earth resistance at major power stations is

 (a) 0.5 ohm (b) 1 ohm (c) 2 ohms (d) 8 ohms

6. Maximum permissible earth resistance at small power stations is

 (a) 0.5 ohm (b) 1 ohm (c) 2 ohms (d) 8 ohms

7. Maximum permissible earth resistance for buildings is

 (a) 0.5 ohm (b) 1 ohm (c) 2 ohms (d) 8 ohms

8. Earth continuity inside an installation i.e. from plate earth to any point in installation

should be

 (a) 0.5 ohm (b) 1 ohm (c) 2 ohms (d) 8 ohms

9 The plate electrode of copper used for earthing should be with minimum size of

 (a) 50cm x 50cm x 3.15mm (b) 50cm x 50cm x 6.3mm

 (c) 60cm x 60cm x 3.15mm (d) 60cm x 60cm x 6.3mm

10 The plate electrode of GI or steel used for earthing should be with minimum size of

 (a) 50cm x 50cm x 3.15mm (b) 50cm x 50cm x 6.3mm

 (c) 60cm x 60cm x 3.15mm (d) 60cm x 60cm x 6.3mm

11 In pipe earthing, the minimum internal diameter for GI pipe should be

 (a) 30 mm (b) 40 mm (c) 50 mm (d) 60 mm

12 In pipe earthing, the minimum internal diameter for cast iron pipe should be

 (a) 80 mm (b) 90 mm (c) 100 mm (d) 60 mm

13 Copper strip electrodes used for earthing should not be less than

 (a) 22.5 mm x 1.60 mm (b) 20 mm x 2.5 mm

 (c) 25 x 1.60 mm (d) 25 mm x 2.5 mm 

 CAMTECH/E/13-14/QB-GS/1.0

December, 2013 Objective Question Bank for General Service

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14 GI or Steel strip electrodes used for earthing should not be less than

 (a) 25 mm x 4mm (b) 20 mm x 3 mm

 (c) 25mm x 3mm (d) 20mm x 4mm

15 Earthing arrangement for HT installations, substations and generating stations should

be inspected at an interval of

(a) 3 months (b) 6 months (c) 9 months (c) 12 months

16 Earthing arrangement for low voltage installations such as service builsings, public

buildings should be inspected at an interval of

 (a) 3 months (b) 6 months (c) 9 months (c) 12 months

17 Earthing arrangement for residential buildings should be inspected at an interval of

 (a) 3 months (b) 6 months (c) 9 months (c) 12 months

18 Earthing arrangement for medium voltage installations should be inspected at an

interval of

 (a) 3 months (b) 6 months (c) 9 months (c) 12 months

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