Interview Question After Completed Electrical Engineering.

 

 

INDEX

1. Wire size

2. Two way switch connection

3. Intermmeadate switch connection

4. Tests  to be made on a new electrical installation befor  it is switched  on to the mains ?

5. How one light control  in Five plase?

6. Why Earthing is require Transformer Neutral?

7. How is a Amp if load 2000W?

8. What is a Cos@

9. Star Delta Connection

10. Why Neutral not present  in the Delta Connection

11. Why Star/Delta Startor use for ?

12.Typs of Pannel

13.Internal Connection of DB

14. If maximum No circuit B7 which No of  Circuit Connected in the  DB?

15.Type of Earth?

16. How to Earthing Test?

17. Corridor Lighting?

18. Type of house wiring?

19.Types of Wire Joint?

20.Type of  Switch

21. Size of Gland?

22. Drawing Scale?

 

v  1.Wire Size

 

       0.5, 0.75, 1.0, 1.5, 2.5, 4, 6, 10, 16,  25, 35, 50, 70, 95 Sq mm.

 

Cable size

           0.5, 0.75, 1.0, 1.5, 2.5, 4, 6, 10, 16, 25, 35, 50, 70, 95, 120, 150, 185, 240, 300, 400, 500, 630, 800, 1000 Sq mm.

 

 

 

v  2.Two Way Switch ?

 

     Two way switch use for one light control two or more  place .

 

 

 

 

 

v  3.Intermediate  Switch ?

 

 

      It is use  for Corridors  lighting and one light Control  more then two place.

 

 

 


 

v  4. Tests  to be made on a new electrical installation befor  it is switched  on to the mains ?

             i. Insulation resistance test between Conductor   and earth.

Befor making test , the conditions to be  fulfilled for the position of the main switch fuses, switches and other points should be as under.

each final sub circuit should have a resistance of at least 0.5 megaohms during the worst condition .

a) The main switch in off position.

b)The fuses beyond the main switch should be in position i.e main fuse is taken out.

c) All switches in  ON position.

d) Lamp and other equipment in their position.

 

 

 

 


 

 

 

       ii.  Insulation resistance test  between  conductor.

The value should not be less then 0.5 Megaohm and not more then  one Mehaohm.

a) The maiiin switch in OFF position.

b) The short circuiting at the main switch not be done.

c) All switch in ON position.

d) The fuses beyond the main switch should be in position. 

 

 

 




 

       iii.  Testing of polarity.

 

 

 


 

 

    iv.  Testing of Earth continuity path.

     v.  Earth resistance test.

 

 

 

 

v  5.  How  to one light control  four place ?

 

 

 

 


 

 

 

v  7.  How is a Amp if load 2000W Single Phase ?

          Single Phase

          W=2000

          W=VI Cos@              

          I= W/V Cos@                       V=220 V

          I =2000/220X0.8                Cos @= 0.8

          I=  11.36 Amp

         3 Phase

                               V= 440 V

         I = 2000/1.732X440X0.8         =1.732

          I=3.28 Amp

v  8. What is Cos@?

                Cos@ is a angels  between  the voltage and Current.

v  




9. 9.Transformer Star/Delta  Connection.






 

v  10. Why Neutral not present  in the Delta Connection?

    mainly two resons               

   i. Delta connection circuit alredy closed.

  ii. Not any common point.

 

 

 

 

 

v  11.  Why  Star/Delta Startor use for ?

 

            Ia=(v-Eb)/Ra

           If full supply voltage is apply across the stationary armatures . It will draw a very large                      current  because  armatures  resistantce is relabelety small . This excessive current  will  blow out  the fuses  an prior  to that , it will  damages  the commutator and brushes etc.

 






                                                            Star/Delta  Starter connection

 

v  12.Typs of Pannel ?   

 i. LT Panel       ii. HT Panel

 i. LT Panel .

 a. Light  Control  Panel                    b. Power  Factor  Control  Panel.

 c.Motor  Control  Center  (MCC)   d. Power  Control  Center (PCC).

 ii. HT Panel .

 a. VCB  Panel .

 

 

 

 

 

 

 

 

v  13. Internal   Connection of DB ?

 

 

 

 

v  



14.  If maximum No circuit B7 Totals  No of  Circuit Connected in the DB?

     R1,Y1,B1............R5,Y5,B5..............R7,Y7,B7.    =   3X7= 21 Circuit .

 

v  15.  Type of Earth?

      i. Plate Earth.  ii. Pipe Earth.  iii. Rod Earthing.  iv.  Strip or Wire Earthing.  v. Waterman Earthing.

 

v  16.  How to Earthing Test?

a) By a portable megger earth tester.

b) By an earth loop tester.

c)By an ohmmeter.

d) By the viltmeter and ammeter using either DC or AC source.

Portabble Digital  Magger Earth Tester.

 

    

 

 


 

v  17.  Corridor Lighting?

 

 





v  18. Type of house wiring?

   i. Concealed  conduit wiring

   ii.Surface conduit wiring

  iii. Metal  sheathed wiring

  iv.C.T.S or Batton wiring .

  v.Wooden casin and capping  wiring .

  vi. Cleat wiring .

 

v  19.Types of Wire Joint?

   i. Straight twist  joint.

  ii.Britanna joint.

  iii. Married joint.

  iv.Scarf joint.

  v.Tee joint.

  vi.Duplex joint.

  vii. Pigtail joint.

v  20. Type of  Switch ?

  i. One way switch

ii. Two Way Switch.

iii.Two Way Center off Switch

iv. Double Pole Man Switch.

 v. Bed Switch.

vi. Push Button Switch.

vii. Intermediate Switch.

 

v  21. Size of Gland ?

Cable(sq mm)

Gland(mm)

300

240

185

150

120

95

70

50

35

25

16

10

63

57

50

45

45s

38

70s

32

28

25

22

19

 

22. Drawing Scale?

Drawng Scale are Three types.

1.Reducing Scale 2. True Scale 3. Large Scale.

 

Thanks you.

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