A. High resistance
B. Medium resistance
C. Negligible resistance
D. Any of the above
Answer: C. Negligible resistance
Explanation:
Earthing is to connect any electrical equipment to earth with a very low resistance wire, making it to attain earth’s potential.
The wire is usually connected to a copper plate placed at a depth of 2.5 to 3 meters from the ground level.
The potential of the earth is considered to be at zero for all practical purposes as the generator (supply) neutral is always earthed.
The body of any electrical equipment is connected to the earth by means of a wire of negligible resistance to safely discharge electric energy, which may be due to failure of the insulation, or line coming in contact with the casing, etc.
Earthing brings the potential of the body of the equipment to ZERO i.e. to the earth’s potential, thus protecting the operating personnel against electrical shock.