MCQs of Electrical Installations (Basic Electrical Engineering - 3110005)

Showing 31 to 40 out of 83 Questions

31.

The advantage of neutral earthing is

(a)	Freedom from persistent arcing grounds
(b)	Over voltages due to lightning can be discharged to earth
(c)	Simplified design earth fault protection
(d)	All of the above

32.

In a star connected system without neutral grounding, zero sequence currents are

(a)	Zero
(b)	Phaser sum of phase currents
(c)	Same as r.m.s. value of phase currents
(d)	Same as peak value of phase currents

33.

The least expensive protection for over current in low-voltage system is

34.

Purpose of backup protection is

(a)	to increase the speed
(b)	to increase a reach
(c)	to leave no blind spot
(d)	to guard against failure of primary

35.

Moisture content in the soil _______________ the soil resistance.

36.

Ground resistance should be designed such that

(a)	grounding resistance should be as low as possible
(b)	grounding resistance should be as high as possible
(c)	grounding resistance should be always zero
(d)	none of the above

37.

The objective of earthing or grounding is

(a)	to provide as low resistance possible to the ground
(b)	to provide ashigh resistance possible to the ground
(c)	to provide flow of positive, negative and zero sequence currents
(d)	none of the above

38.

Factors on which soil resistance depends

39.

Earth wire or ground wire is made of

40.

The size of the earth or ground wire is based on the

(a)	maximum fault current carrying through the ground wire
(b)	rated current carrying capacity of the service line
(c)	depends on the soil resistance
(d)	both A and C

Showing 31 to 40 out of 83 Questions