Objective Questions on wiring installation and earthing for Electrician Trade
| Sr. No. | Questions with options |
| 1 | What is the minimum size of copper earth continuity conductor used in single phase domestic wiring as per BIS?
(a) 3 Sq. mm (b) 3.5 Sq.mm (c) 2.5 Sq.mm (d) 1.5 Sq. mm Ans- (d) |
| 2 | Which method is used to reduce earth resistance value in a existing earth?
(a) Increasing the length of electrode (b) Keeping wet condition in earth pits always (c) Adding more sand and charcoal in earth pits (d) Increasing the diameter of earth electrode Ans_ (b) |
| 3 | Why A.C is required to measure the earth resistance by using earth resistance tester?
(a) Regulate the current (b) Increase the voltage drop (c) Decrease the voltage drop (d) Avoid electrolytic emf interference Ans – (d) |
| 4 | What is the formula to find voltage drop of a A.C single phase wiring circuit?
(a) Voltage drop = IR volt (b) Voltage drop = I2R volt (c) Voltage drop = I/R volt (d) Voltage drop =IR/2 volt Ans- (a) |
| 5 | What is the maximum permissible load for a power sub circuit as per I.E rules?
(a) 800 watt (b) 1500 watt (c) 2000 watt (d) 3000 watt Ans – (d) |
| 6 | Which location the service connection supply leads to be connected at consumer main board?
(a) IC cut out (b) Main switch (c) Energy meter (d) Distribution board Ans – (c) |
| 7 | What is the permissible leakage current in domestic wiring installation?
(a) Full load current/ 5 (b) Full load current/ 50 (c) Full load current/ 500 (d) Full load current/ 5000 Ans _ (d) |
| 8 | Which formula is used to calculate the diversity factor?
(a) Diversity factor = Maximum load/ installed load (b) Diversity factor = installed load/ maximum load (c) Diversity factor = minimum actual load/ installed load (d) Diversity factor = installed load/ minimum actual laod Ans –(c) |
| 9 | Which instrument is used to test new domestic wiring installation?
(a) Multimeter (b) Megger (c) Shunt type ohmmeter (d) Series type ohmmeter Ans – (b) |
| 10 | Where system earthing is done?
(a) Generating station (b) Electroplating installation (c) Small industrial installation (d) Domestic wiring installation Ans – (a) |
| 11 | What is the test to be carried out by using megger?
(a) Polarity test (b) Insulation resistance test (c) Earth electrode resistance test (d) Earth conductor continuity test Ans – (b) |
| 12 | What is the reason of lamp glowing dim and motor running slow in domestic wiring circuit?
(a) Open circuit in the neutral line (b) Short circuit between conductor (c) High value series resistance fault (d) Open circuit in the earth conductor Ans – (c) |
| 13 | Which wiring installation the system earthing is to be done?
(a) Substations (b) Godown wiring (c) Domestic wiring (d) Commercial wiring Ans – (a) |
| 14 | How to control harmonic distortion in neutral connections as per IE rule?
(a) Earthing through impedance (b) Providing by plate earthing (c) Increasing conductor size (d) Providing parallel earthing Ans- (a) |
| 15 | What is the function of current reverser in earth resistance tester?
(a) Converts A.C into D.C (b) Reverses the polarity of D.C (c) Changes D.C supply into A.C supply (d) Reverses the direction of rotation of the generator Ans – (c) |
| 16 | What is the advantage of stranded conductor over solid conductor?
(a) Cost is less (b) More flexible (c) Less voltage drop (d) More insulation resistance Ans- (b) |
| 17 | How the earth resistance can be reduced?
(a) Providing double earthing (b) Reducing the pit depth for earthing (c) Increasing the length of the electrodes (d) Decreasing the length of the electrodes Ans- (a) |
| 18 | What is the reason for supplying AC to the electrodes for measuring earth resistance?
(a) Provide electrostatic shield (b) Protect the coils in the meter (c) Reduce the value of current in the meter (d) Avoid the effect of electrolytic emf interference Ans – (d) |
| 19 | Why the pointer is NOT stable at zero on the scale as the megger is NOT in use?
(a) It is not having controlling Torque (b) Provided with air friction damping (c) The deflecting torque is directly proportional to the current (d) The deflecting torque is directly proportional to the square of the current Ans- (a) |
| 20 | Which is proportional for the deflection of ohmmeter needle in earth resistance tester?
(a) Current in current coil (b) Current in potential coil (c) Speed of the handle rotation (d) Ratio of the current in two coils Ans – (d) |
| Published On – 5th June 2022 | |
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