WIRING INSTALLATION AND EARTHING - Quiz

1) How the earth resistance can be reduced?

Providing double earthing Reducing the pit depth for earthing Increasing the length of the electrodes Decreasing the length of the electrodes

2) What is the reason for supplying AC to the electrodes for measuring earth resistance?

Provide electrostatic shield Protect the coils in the meter Reduce the value of current in the meter Avoid the effect of electrolytic emf interference

3) Why the pointer is not stable at zero on the scale as the megger is not in use?

It is not having controlling Torque Provided with air friction damping The deflecting torque is directly proportional to the current The deflecting torque is directly proportional to the square of the current

4) Which is proportional for the deflection of ohmmeter needle in earth resistance tester?

Current in current coil Current in potential coil Speed of the handle rotation Ratio of the current in two coils

5) Which principle the earth resistance tester works?

Self induction Mutual induction Fall of potential method Fleming?s left hand rule