16. S&T earthing

Moisture must be maintained at least

• 20%

• 30%

• 40%

• 50%

Diameter of the pipe in earthing must be more than

• 28 mm

• 30 mm

• 32 mm

• 34 mm

Which of these are included in earthing?

• Pipe Earthing

• Maintenance free Earthing

• Plate Earthing

• All of the above

Length of GI Pipe in pipe earthing

• 3 mtr

• 5 mtr

• 6 mtr

• 8 mtr

Excavated pit around the G.I pipe is filled with salt and coal mixture

• True

• False

Size of copper plate used in plate earthing

• 1200 mm x 1200 mm x 3 mm

• 1200 mm x 1200 mm x 5 mm

• 1200 mm x 1200 mm x 7 mm

• 1200 mm x 1200 mm x 9 mm

Diameter of the earth electrode in maintenance free earthing

• 17 mm

• 19 mm

• 21 mm

• 23 mm

In Maintenance Free Earthing, earth electrode is a Zinc coated steel rod

• True

• False

The digital earth tester has ____ terminals

• 4

• 6

• 8

• 10

Maximum allowable Earth resistance For signal installations is

• 6 ohms

• 8 ohms

• 10 ohms

• 12 ohms