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.
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
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
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
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
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