60 TOP Cables - Electrical Engineering Multiple choice Questions and Answers pdf download

Real Time Electrical Cable Online Quiz Questions and Answers

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1. The insulating material for a cable should have
(a) low cost
(b) high dielectric strength
(c)     high mechanical strength
(d) all of the above
Ans: d

2. Which of the following protects a cable against mechanical injury ?
(a)     Bedding
(b)     Sheath
(c)     Armouring
(d)     None of the above
Ans: c

3. Which of the following insulation is used in cables ?
(a) Varnished cambric
(b) Rubber
(c)     Paper
(d)     Any of the above
Ans: d

4. Empire tape is
(a) varnished cambric
(b) vulcanised rubber
(c)     impregnated paper
(d)     none of the above
Ans: a


5. The thickness of the layer of insulation on the conductor, in cables, depends upon
(a)     reactive power
(b)     power factor
(c) voltage
(d) current carrying capacity
Ans: c

6. The bedding on a cable consists of 
(a)     hessian cloth  
(b)     jute
(c) any of the above
(d) none of the above
Ans: c

7. The insulating material for cables should
(a)     be acid proof
(b)     be non-inflammable
(c) be non-hygroscopic
(d) have all above properties
Ans: d

8. In a cable immediately above metallic sheath _____ is provided.
(a)     earthing connection
(b)     bedding
(c)     armouring
(d)     none of the above
Ans: b


9. The current carrying capacity of cables in D.C. is more thanthat in A.C. mainly due to
(a)     absence of harmonics
(b)     non-existence of any stability limit
(c) smaller dielectric loss
(d) absence of ripples
(e) none of the above
Ans: c

10.   In case of three core flexible cable the colour of the neutral is
(a)     blue
(b)     black
(c) brown
(d) none of the above
Ans: a

11 cables are used for 132 kV lines.
(a)     High tension  
(b)     Super tension
(c) Extra high tension
(d) Extra super voltage
Ans: d

12. Conduit pipes are normally used to protect _____ cables.
(a) unsheathed cables
(b) armoured
(c) PVC sheathed cables
(d) all of the above
Ans: a

13. The minimum dielectric stress in a cable is at
(a)     armour
(b)     bedding
(c) conductor surface
(d) lead sheath
Ans: d

14. In single core cables armouring is not done to
(a)     avoid excessive sheath losses
(b)     make it flexible
(c) either of the above
(d) none of the above
Ans: a

15. Dielectric strength of rubber is around
(a)     5 kV/mm
(b)     15 kV/mm
(c)     30 kV/mm
(d)     200 kV/mm
Ans: c

16. Low tension cables are generally used upto
(a)     200 V
(b)     500 V
(c)     700 V
(d)     1000 V
Ans: d

17. In a cable, the maximum stress under operating conditions is at
(a)     insulation layer
(b)     sheath
(c)     armour
(d)     conductor surface
Ans: d

18. High tension cables are generally used upto
(a)     11kV
(b)     33kV
(c)     66 kV
(d)     132 kV
Ans: a

19. The surge resistance of cable is 
(a)     5 ohms
(b)     20 ohms
(c)     50 ohms          
(d)     100 ohms
Ans: c

20. PVC stands for
(a)     polyvinyl chloride
(b)     post varnish conductor
(c) pressed and varnished cloth
(d) positive voltage conductor
(e) none of the above
Ans: a

21. In the cables, the location of fault is usually found out by comparing
(a) the resistance of the conductor
(b) the inductance of conductors
(c) the capacitances of insulated conductors
(d) all above parameters
Ans: c

22. In capacitance grading of cables we use a ______ dielectric.
(a)     composite
(b)     porous
(c)     homogeneous  
(d)     hygroscopic
Ans: a

23. Pressure cables are generally not used beyond
(a)     11 kV
(b)     33 kV
(c)     66 kV
(d)     132 kV
Ans: c

24. The material for armouring on cable is usually
(a)     steel tape
(b)     galvanised steel wire
(c) any of the above
(d) none of the above
Ans: c

25. Cables, generally used beyond 66 kV are
(a)     oil filled
(b)     S.L. type
(c)     belted
(d)     armoured
Ans: a

26. The relative permittivity of rubber is
(a) between 2 and 3
(b) between 5 and 6
(c) between 8 and 10
(d) between 12 and 14
Ans: a

27. Solid type cables are considered unreliable beyond 66 kV because
(a)     insulation may melt due to higher temperature
(b)     skin effect dominates on the conduc¬tor
(c) of corona loss between conductor and sheath material
(d) there is a danger of breakdown of insulation due to the presence of voids
Ans: d

28. If the length of a cable is doubled, its capacitance
(a) becomes one-fourth
(b) becomes one-half
(c) becomes double
(d) remains unchanged
Ans: c

29. In cables the charging current
(a) lags the voltage by 90°
(b) leads the voltage by 90°
(c) lags the voltage by 180°
(d)     leads the voltage by 180°
Ans: b

30. A certain cable has an insulation of relative permittivity 4. If the insulation is replaced by one of relative permittivity 2, the capacitance of the cable will become
(a)     one half
(6)     double
(c) four times
(d)     none of the above
Ans: a

31. If a cable of homogeneous insulation has a maximum stress of 10 kV/mm, then the dielectric strength of insulation should be
(a)     5 kV/mm
(b)     10 kV/mm
(a)     15 kV/mm
(d)     30 kV/mm
Ans: b

32. In the cables, sheaths are used to
(a)     prevent the moisture from entering the cable
(b)     provide enough strength
(e) provide proper insulation
(d) none of the above
Ans: a

33. The intersheaths in the cables are used to
(a)     minimize the stress
(b)     avoid the requirement of good insulation
(c) provide proper stress distribution
(d) none of the above
Ans: c

34. The electrostatic stress in underground cables is
(a)     same at the conductor and the sheath
(b)     minimum at the conductor and maximum at the sheath
(c)     maximum at the conductor and minimum at the sheath
(d) zero at the conductor as well as on the sheath
(e) none of the above
Ans: c

35. The breakdown of insulation of the cable can be avoided economically by the use of
(a) inter-sheaths
(b) insulating materials with different dielectric constants
(c) both (a) and (b)
(d) none of the above
Ans: c

36. The insulation of the cable decreases with
(a) the increase in length of the insulation
(b) the decrease in the length of the insulation
(c) either (a) or (b)
(d) none of the above
Ans: a

37. A cable carrying alternating current has
(a) hysteresis losses only
(b) hysteresis and leakage losses only
(c) hysteresis, leakage and copper losses only
(d) hysteresis, leakage, copper and friction losses
Ans: b

38. In a cable the voltage stress is maximum at
(a)     sheath
(6)     insulator
(e) surface of the conductor
(d)     core of the conductor
Ans: d

39. Capacitance grading of cable implies
(a) use of dielectrics of different permeabilities
(b) grading according to capacitance of cables per km length
(c) cables using single dielectric in different concentrations
(d) capacitance required to be introduced at different lengths to counter the effect of inductance
(e) none of the above
Ans: a

40. Underground cables are laid at sufficient depth
(a)     to minimise temperature stresses
(b)     to avoid being unearthed easily due to removal of soil
(c) to minimise the effect of shocks and vibrations due to gassing vehicles, etc.
(d) for all of the above reasons
Ans: c

41. The advantage of cables over overhead transmission lines is
(a)     easy maintenance
(b)     low cost
(c) can be used in congested areas
(d) can be used in high voltage circuits
Ans: c

42. The thickness of metallic shielding on cables is usually
(a)     0.04 mm
(b)     0.2 to 0.4 mm
(e) 3 to 5 mm
(d)     40 to 60 mm
Ans: a

43. Cables for 220 kV lines are invariably
(a)     mica insulated
(b)     paper insulated
(c) compressed oil or compressed gas insulated
(d) rubber insulated
(e) none of the above
Ans: c

44. Is a cable is to be designed for use on 1000 kV, which insulation would you prefer ?
(a)     Polyvinyle chloride
(b)     Vulcanised rubber
(c) Impregnated paper
(d) Compressed SFe gas
(e) none of the above
Ans: d

45. If a power cable and a communication cable are to run parallel the minimum distance between the two, to avoid interference, should be
(a)     2 cm
(b)     10 cm
(c)     50 cm
(d)     400 cm
Ans: c

46. Copper as conductor for cables is used as
(a) annealed
(b) hardened and tempered
(c) hard drawn
(d) alloy with chromium
Ans: a

47. The insulating material should have
(a) low permittivity
(b) high resistivity
(c) high dielectric strength
(d) all of the above
Ans: d

48. The advantage of oil filled cables is
(a) more perfect impregnation
(b) smaller overall size
(c) no ionisation, oxidation and formation of voids
(d) all of the above
Ans: d

49. The disadvantage with paper as insulating material is
(a)     it is hygroscopic
(6)     it has high capacitance
(c) it is an organic material
(d) none of the above
Ans: a

50. The breakdown voltage of a cable depends on
(a)     presence of moisture
(b)     working temperature
(c) time of application of the voltage
(d) all of the above
Ans: d

51. It is difficult to maintain oil filled cables.
(a)   Yes
(b)   No
Ans: a

51. In capacitance grading a homogeneous dielectric is used.
(a)   Yes
(b)   No
Ans: b

52. In congested areas where excavation is expensive and inconvenient 'draw in system' of laying of underground cables
is often adopted.
(a)   Yes
(b)   No
Ans: a

53. Natural rubber is obtained from milky sap of tropical trees.
(a)   Yes
(b)   No
Ans: a

54. Rubber is most commonly used insulation in cables.
(a)   Yes
(b)   No
Ans: a

55. Polyethylene has very poor dielectric and ageing properties.
(a)   Yes
(b)   No
Ans: b

56. The metallic sheath may be made of lead or lead alloy or of aluminium.
(a)   Yes
(b)   No
Ans: b

Latest Electrical Cable Objective type Questions for freshers

TOP Cable Installer Interview Questions and Answers pdf download

1. On a typical day, what are your work activities on the whole?
Each day is different. No day is typical really. However, some of the jobs that I perform on a regular basis include troubleshooting cabling problems, installing new cables, removing old ones and modifying, adjusting and replacing malfunctioning equipment.

2. What type of skills do you offer as a cable installer?
I am extremely dexterous when it comes to physical work. I can climb high poles and work in cramped areas with ease. I am also proficient in handling tools and equipment to help me during troubleshooting and installation processes. Furthermore, I am extremely well-versed in managing routine maintenance of structured cabling systems.

3. Doesn’t it bother you to climb high poles and work in confined spaces?
It doesn’t actually. Climbing distances upwards and working in claustrophobic areas is all in a day’s work for cable installers. I am trained in keeping my cool even when a certain situation does seem threatening to me.

4. Do you think customer education is important in this role? Why or why not?
Customer education is very important. This is because it minimizes downtime of their equipment and makes it easy for cable installers to understand and troubleshoot problems, when customers describe them.

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TOP 10 Cable Technician Interview Questions Answers freshers experienced pdf

Real Time Electrical Cable Technician Interview Questions with Answers PDF

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1. What makes you a viable choice to hire as a cable technician to represent our company?
With over 4 years of experience working as a cable technician, and having started from humble beginnings (as an apprentice initially), I believe that I know all there is to know about cable installation at this point in time. Also, I am a quick learner which makes it easy for me to learn new technologies and procedures in a prompt manner. Additionally, I possess both functional and technical skills that are needed to handle all complex cable installation and maintenance activities.

2. On any typical day at work, what duties have you performed in a cable technician’s role?
On most days at work, I have been responsible for planning cable network installations by studying clients’ orders, associated manuals and specifications, and looking through technical specifications. Establishing both voice and data networks by performing running, pulling, terminating and splicing duties is all in a day’s work for me. Verifying services by testing circuits and alarms, and identifying and escalating problems is also something that I do on any typical day at work.

3. How do you deal with the physical aspect of working as a cable technician?
Thankfully, I do not have to deal with the impact of physical work that a cable technician is supposed to do. I am a physically agile individual, which makes it easy for me to crouch in small places and climb ladders and roofs easily. I never need to think about any physical limitations.

4. How do you deal with adversity at work?
Adversity is a constant in any work, especially that of a cable technician. If it isn’t the weather hampering our work, it is a client who fails to understand the limitations of their service, or our limitations as humans. I usually take things in stride and try to deal with them in a way that they do not affect my work in a negative manner.


5. If you were told by a client that he or she is dissatisfied with your work, how would you deal with it?
My first reaction would be to apologize. I would then delve deep into why the client thought my work wasn’t up to the mark, and then try to make sure that I do not leave a dissatisfied client behind!

6. What technical specifications of cable installation and maintenance are you familiar with?
I am well-versed in cabling and termination of CAT3, CAT4, CAT5 and CAT6 wiring disciplines, along with possessing solid knowledge of cabling standards such as ANSI / TIA / EIA, NFPA and IEEE.

7.  Tell me about your ability to work under pressure?
You may say that you thrive under certain types of pressure. Give an example that relates to the type of position applied for.
Mention routine pressure you face, such as dealing with deadlines on a regular basis.
Try not to use an example where you created the pressure yourself, by waiting too long to start something, or by handling a task irresponsibly at the beginning. For example, working under pressure to meet a customer’s deadline could be a good example, but not if you had waited too long to start the project.

8. What field experience do you have for a CABLE TECHNICIAN POSITION?
Speak about specifics that relate to the position you are applying for. If you do not have specific experience, get as close as you can.
If you are being asked this question from your employer then you can explain your experience. Tell the employer what responsibilities you were performing during your job. You can tell what programs you developed and what modules you worked on. What were your achievements regarding different programs.
I have been working with computers since 2001. I also have a degree in network support/computer repair. I have built my last 3 computers, have work with Dell as an employee. So I have around 15 years experience working with computers.

Latest Cable Technician Interview Questions for freshers and Experienced pdf

5 TOP Cables - Electrical Engineering Interview Questions Answers pdf download

Real Time Electrical Cables Interview Questions with Answers PDF

1. What is the main reason for providing metallic sheath in underground cables?

Answer: The metallic sheath is provided around the insulation to protect it against the ingress of moisture, gas and other damaging liquids (acid or alkalies) from the soil and atmosphere

2. What are the main requirements of the insulation materials used for underground cables?
Answer: Some the properties that insulation material require to possess are high insulation resistivity, high dielectric strength, good mechanical properties, non-hygroscopic, non inflammable, immune to attacks by acids and alkalies

3. What are the advantages and disadvantages of oil filled cables?
Answer: Some of the advantages and disadvantages of oil filled cables are listed below:
Advantages:
Smaller overall size and smaller weight for given voltage and kVA rating due to reduction in the thickness of the dielectric required
No ionization, oxidation and formation of voids
More perfect impregnation
Smaller thermal resistance due to decrease in the dielectric thickness, so higher current rating
More maximum permissible stresses
Fault identification is easy
Disadvantages:
Greater cost
Complicated laying of cables and maintenance


4. Advantages of XLPE cables compared to PVC cables?
Answer:
 XLPE cable can withstand higher temperature (900C) compared to PVC (700C)
XLPE cables can have higher over-load capacity
XLPE cables are lighter in weight and smaller bend radius hence lower installation cost
XLPE cable has high short circuit rating
It has lower dielectric and constant power factor which can result in saving of power


5. What are different insulation materials used in cables for high voltage and medium voltage?
Answer:
Medium Voltage:
Polyethylene (PE)
Cross linked polyethylene (XLPE)
Tree retardant cross linked polyethylene (TR-XLPE)
Ethylene-Propylene Elastomers (EPR)
PILC
High Voltage:
Cross linked polyethylene (XLPE)
Paper/Oil
Paper/Polypropylene
SF6 gas

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Latest Electrical Cables Interview Questions for freshers and Experienced pdf