Earthing & Lightning Protection

Which of the following is not correct about Earthing :-

• To provide a sufficiently low impedance path to facilitate satisfactory Protective system operation under fault conditions.

• To ensure that living beings are not exposed to unsafe potentials

• It is not possible to operate the electrical system without Earthing

• None

Earthing & Grounding are :-

• Same

• Different

• Same in some part of India & different in some other part of India

• None

Physiological Effects of 4 A AC Current in Human Body:-

• Barely perceptible

• Painful sensation

• Heart paralysis

• None

"Soil resistivity" & “Resistance” are :-

• Same thing

• Different

• Could not be predict

• None

Which of the following is not the type of earthing :-

• System Earthing

• Equipment Earthing

• earthing device

• None

Which of the following is the purpose of System Earthing ?

• Controls Voltage to ground to specified limits.

• Limits voltage stress on Insulation of conductors

• Provides path for flow of currents during Fault

• All of the above

Which of the following are the ADVANTAGES OF EARTHED SYSTEM :-

• The system earthing (solidly or through a resistance or impedance) is done to provide a return path of earth fault current, which in turn helps

• To reduce the insulation requirement of phase elements of equipment connected in that voltage level & cost of the equipment/s in turn. VIZ: Earthed grade cables are less costly than unearthed grade cables.

• To isolate the faulty part of the system due to earth fault by sensing earth fault current

• All of the above

Which of the following are the Type of Earth Electrodes :-

• Treated Earth pit

• Directly driven earth electrode

• Deep bore earth electrode

• All of the above