Cables

21. In case of three core flexible cable the colour of the neutral is

1. blue
2. black
3. brown
4. none of the above

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22. In single core cables armouring is not done to

1. avoid excessive sheath losses
2. make it flexible
3. either of the above
4. none of the above

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23. In the cables, sheaths are used to

1. prevent the moisture from entering the cable
2. provide enough strength
3. provide proper insulation
4. none of the above

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24. Is a cable is to be designed for use on 1000 kV, which insulation would you prefer?

1. Polyvinyle chloride
2. Vulcanised rubber
3. Impregnated paper
4. Compressed SFe gas

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25. Low tension cables are generally used up to

1. 200 V
2. 500 V
3. 700 V
4. 1000 V

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26. Pressure cables are generally not used beyond

1. 11 kV
2. 33 kV
3. 66 kV
4. 132 kV

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27. PVC stands for

1. polyvinyl chloride
2. post varnish conductor
3. pressed and varnished cloth
4. positive voltage conductor

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28. Solid type cables are considered unreliable beyond 66 kV because

1. insulation may melt due to higher temperature
2. skin effect dominates on the conductor
3. of corona loss between conductor and sheath material
4. there is a danger of breakdown of insulation due to the presence of voids

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29. The advantage of cables over overhead transmission lines is

1. easy maintenance
2. low cost
3. can be used in congested areas
4. can be used in high voltage circuits

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30. The advantage of oil filled cables is

1. more perfect impregnation
2. smaller overall size
3. no ionisation, oxidation and formation of voids
4. all of the above

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