Electrical Cables Interview Questions & Answers

Posted On:February 3, 2019, Posted By: Latest Interview Questions, Views: 7154, Rating :

Best Electrical Cables Interview Questions and Answers

Dear Readers, Welcome to Electrical Cables Interview Questions and Answers have been designed specially to get you acquainted with the nature of questions you may encounter during your Job interview for the subject of Electrical Cables. These Electrical Cables Questions are very important for campus placement test and job interviews. As per my experience good interviewers hardly plan to ask any particular questions during your Job interview and these model questions are asked in the online technical test and interview of many IT & Non IT Industries.

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

Interview Questions on Electrical Cables

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:


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 


Greater cost

Complicated laying of cables and maintenance


4. Advantages of XLPE cables compared to PVC cables?


 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?


Medium Voltage:

Polyethylene (PE)

Cross linked polyethylene (XLPE)

Tree retardant cross linked polyethylene (TR-XLPE)

Ethylene-Propylene Elastomers (EPR)


High Voltage:

Cross linked polyethylene (XLPE)



SF6 gas