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

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

(d) all of the above
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Related questions

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

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

Last Answer : (d) all of the above

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

Description : 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

Last Answer : (c) both (a) and (b)

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

Description : 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

Last Answer : (b) 10 kV/mm

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

Description : 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

Last Answer : (a) it is hygroscopic

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

Description : 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 ... introduced at different lengths to counter the effect of inductance (e) none of the above

Last Answer : (a) use of dielectrics of different permeabilities

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

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

Last Answer : (d) lead sheath

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

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

Last Answer : (c) 30 kV/mm

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

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

Last Answer : (d) have all above properties

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

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

Last Answer : (c) Armouring

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

Description : 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

Last Answer : (a) prevent the moisture from entering the cable

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

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

Last Answer : (b) No

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

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

Last Answer : (b) No

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

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

Last Answer : (a) composite

The current carrying capacity of cables in D.C. is more that 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

Description : The current carrying capacity of cables in D.C. is more that 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

Last Answer : (c) smaller dielectric loss

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

Description : 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

Last Answer : (c) any of the above

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

Description : 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

Last Answer : (c) can be used in congested areas

What is dielectric strength of an insulating material? What is its unit?

Description : What is dielectric strength of an insulating material? What is its unit?

Last Answer : Dielectric Strength: The dielectric strength of an insulating material is the maximum voltage which the insulating medium can withstand without breakdown. Unit is volts per millimeter (V/mm), or kV/mm or kV/cm

For an insulating material, dielectric strength and dielectric loss should be respectively

Description : For an insulating material, dielectric strength and dielectric loss should be respectively   (A) high and high (B) low and high (C) high and low (D) low and low.

Last Answer : For an insulating material, dielectric strength and dielectric loss should be respectively  high and low 

What is the type cable used in radiation areas?

Description : What is the type cable used in radiation areas?

Last Answer : Mineral insulated (MI) cables. 

What is the specified cable life?

Description : What is the specified cable life? 

Last Answer : 50 years.  

What are the purposes of cable trays?

Description : What are the purposes of cable trays? 

Last Answer : a. Avoid sagging of cables b. Give mechanical support 

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

Description : 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

Last Answer : (d) all of the above

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

Description : 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

Last Answer : (c) 50 cm

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

Description : 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

Last Answer : (d) Compressed SFe gas

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

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

Last Answer : (d) core of the conductor

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

Description : 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

Last Answer : (b) hysteresis and leakage losses only

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

Description : 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

Last Answer : (a) the increase in length of the insulation

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

Description : 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

Last Answer : (a) one half

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

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

Last Answer : (c) becomes double

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

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

Last Answer : (c) 50 ohms

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

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

Last Answer : (d) conductor surface

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

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

Last Answer : (a) blue

In a cable immediately above metallic sheath _____ is provided. (a) Earthing connection (b) Bedding (c) Armouring (d) None of the above

Description : In a cable immediately above metallic sheath _____ is provided. (a) Earthing connection (b) Bedding (c) Armouring (d) None of the above

Last Answer : (b) Bedding

The bedding on a cable consists of (a) Hessian cloth (b) Jute (c) Any of the above (d) None of the above

Description : The bedding on a cable consists of (a) Hessian cloth (b) Jute (c) Any of the above (d) None of the above

Last Answer : (c) Any of the above

Dielectric (A) Is an electrical insulating material (B) Of low resistivity is preferred (C) Should have high thermal conductivity (D) Need not defy the corrosive action of chemicals

Description : Dielectric (A) Is an electrical insulating material (B) Of low resistivity is preferred (C) Should have high thermal conductivity (D) Need not defy the corrosive action of chemicals

Last Answer : (A) Is an electrical insulating material

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

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

Last Answer : (d) there is a danger of breakdown of insulation due to the presence of voids

Low tension cables are generally used up to (a) 200 V (b) 500 V (c) 700 V (d) 1000 V

Description : Low tension cables are generally used up to (a) 200 V (b) 500 V (c) 700 V (d) 1000 V

Last Answer : (d) 1000 V

High tension cables are generally used up to (a) 11kV (b) 33kV (c) 66 kV (d) 132 kV

Description : High tension cables are generally used up to (a) 11kV (b) 33kV (c) 66 kV (d) 132 kV

Last Answer : (a) 11kV

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

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

Last Answer : (d) Extra super voltage

Mica is a (A) Dielectric material. (B) Insulating material. (C) Magnetic material. (D) Both insulating and dielectric material.

Description : Mica is a (A) Dielectric material. (B) Insulating material. (C) Magnetic material. (D) Both insulating and dielectric material.

Last Answer : (D) Both insulating and dielectric material.

Define dielectric failure of electrical insulating material.

Description : Define dielectric failure of electrical insulating material. 

Last Answer : Definition of dielectric failure of electrical insulating material. In the insulating material if the applied voltage is increased gradually then for certain value insulation will break down, ... material vanishes its insulating properties and starts conducting, also known as dielectric failure.

State failure phenomena observed in insulating material. State four reasons for failure of gaseous and solid dielectric materials.

Description : State failure phenomena observed in insulating material. State four reasons for failure of gaseous and solid dielectric materials. 

Last Answer : Failure phenomena in insulating material means the dielectric property fails :  The dielectric failure mean the dielectric strength of insulating material reduces due to high voltages or high ... 6. Due to poor maintenance of insulating material there may be possibility dielectric failure 

Gold and silver are (A) dielectric materials (B) low resistivity conducting materials. (C) magnetic materials. (D) insulating materials.

Description : Gold and silver are (A) dielectric materials (B) low resistivity conducting materials. (C) magnetic materials. (D) insulating materials.

Last Answer : (B) low resistivity conducting materials.

Why bimetallic washers provided in aluminium copper transition joints?

Description : Why bimetallic washers provided in aluminium copper transition joints?

Last Answer : To avoid galvanic corrosion failure.  

Why 1.1 kV grade cables used for 415V?

Description : Why 1.1 kV grade cables used for 415V?

Last Answer : To take care of the both earthed / unearthed systems.  

What are the types of cables used in 6.6 kV and 415 V system voltages?

Description : What are the types of cables used in 6.6 kV and 415 V system voltages? 

Last Answer : In 6.6 kV system AC (unearthed) grade having stranded aluminium conductors cables are used. Their insulation's are as follows. 1. XLPE - Crossed linked polyethylene insulation. 2. FRLS PVC - Fire ... V grade copper or aluminium stranded cables are used. Their insulations are HR PVC and FS type. 

How the required conductor size can be reduced by use of HRC fuses?

Description : How the required conductor size can be reduced by use of HRC fuses?

Last Answer : HRC fuse limits the peak amplitude of fault current. HRC fuse melts at prospective current but not allows circuit to pass their high rupturing capacity that is it’s kA. 

Why armouring done?

Description : Why armouring done?

Last Answer : For mechanical strength, protect against damage by impact of an object.  

How armours /sheaths grounded?

Description : How armours /sheaths grounded? 

Last Answer : 1 core cables -- sheaths/shields/armours grounded at one end only, other end insulated to prevent the circulating current through sheaths. 3 core cables -- grounded at both ends but not including core balance CT’s, since even small induced current causes 50N operation. 

What are the advantages of XLPE?

Description : What are the advantages of XLPE? 

Last Answer : a. Easy routing at heights b. Easy maintenance c. Large current (90 ºC) d. No sheath (no fatigue) e. No paper tape wrapping technique f. High dielectric strength g. Very little deformation ... i. Low tan delta and hence suits long routes j. Very light k. Good mechanical properties.