EARTHING

What is the minimum size of Copper earth continuity conductor used in single phase domestic wiring as per BIS? 3 Sq.mm 3.5 Sq.mm 2.5 Sq.mm 1.5 Sq.mm

Which method is used to reduce earth resistance value in a existing earth? Increasing the length of electrode Keeping wet condition in earth pits always Adding more sand and charcoal in earth pits Increasing the diameter of earth electrode

Why A.C is required to measure the earth resistance by using earth resistance tester? Regulate the current Increase the voltage drop Decrease the voltage drop Avoid electrolytic emf interference

What is the formula to find voltage drop of a A.C single phase wiring circuit? Voltage drop = IR volt Voltage drop = I2R volt Voltage drop = I/R volt Voltage drop=IR/2 volt

What is the maximum permissible load for a power sub circuit as per l.E rules? 800 Watt 1500 Watt 2000 Watt 3000 Watt

Which location the service connection supply leads to be connected at consumer main board? IC cut out Main switch Energy meter Distribution board

What is the type of test in domestic wiring installation?

Polarity test Continuity (or) open circuit test Insulation resistance test between conductors Insulation resistance test between conductors and earth

What is the permissible leakage current in domestic wiring installation? 1/5 x Full load current 1/50 x Full load current 1/500 x Full load current 1/5000 x Full load current

Which formula is used to calculate the diversity factor? Diversity Factor = Maximum Load/Installed Load Diversity Factor = Installed load/Minimum load Diversity Factor = Minimum actual load/Installed load Diversity Factor = Installed load/Minimum actual load

Which instrument is used to test new domestic wiring installation? Multimeter Megger Shunt type ohmmeter Series type ohmmeter

Where system earthing is done? Generating station Electroplating installation Small industrial installation Domestic wiring installation

What is the test to be carried out by using megger? Polarity test Insulation resistance test Earth electrode resistance test Earth conductor continuity test

What is the reason of lamp glowing dim and motor running slow in a domestic wiring circuit? Open circuit in the neutral line Short circuit between conductors High value series resistance fault Open circuit in the earth conductor

Which wiring installation the System earthing is to be done? Substations Godown wiring Domestic wiring Commercial wiring

Which method of earth resistance measurement is illustrated?

Fall of current Fall of potential Current dividing Potential dividing

How to control harmonic distortions in neutral connections as per IE rule? Earthing through impedance Providing by plate earthing Increasing conductor size Providing parallel earthing

What is the function of current reverser in earth resistance tester? Converts A.C. into D.C Reverses the polarity of D.C Changes D.C. supply into A.C supply Reverses the direction of rotation of the generator

What is the advantage of stranded conductor over solid conductor? Cost is less More flexible Less voltage drop More insulation resistance

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

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

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

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

Which principle the earth resistance tester works? Self induction Mutual induction Fall of potential method Fleming's left hand rule

Why system earthing is different in utilization than equipment earthing? It protects human only It protects from all circuit faults It is associated with current carrying conductors It is connected to the non current carrying metal work

What is the effect if a person receives a shock current of 20 mA? No sensation Painful shock Heart convulsions Become unconscious

Which electrical equipment L series type MCB's are used? Geysers Locomotives Halogen lamps Air conditioners

What is the megger reading in a dead short wiring installation? 0MW 1 MW 500 MW Infinity

What is the advantage of crimping? Gives neat appearance Reduce load current Avoid loose connections Easy to replace