Saturday, October 3, 2015

Difference between XLPE and PVC Cables

Difference between XLPE and PVC Cables

XLPE - is cross linked polyethylene cable. 

Main Thumb rule for differentiation is that XLPE cables can be used for both HT and LT lines.
But PVC Cables can be used only for LT lines.

XLPE can withstand a higher temperature than PVC without detriment. This means that more current can be conducted for the same cross sectional area of copper. This means a big saving in cables costs. 

XLPE Cables useful properties are:-

1. Temperature resistance
2. Stress rupture resistance
3. Environmental stress crack resistance
4. Resistance to U.V light
5. Chemical resistance
6. Oxidation resistance

XLPE Cables can be useful for following applications:-

1) XLPE cables work for the working voltage of 240 V to 500 KV .
2) Conductor Material can be either Copper or Aluminum.
3) XLPE cables can be either Single Core cables or Multi core cables depending upon the number of
cores.
4) They can be Unarmoured or Strip Armoured or Wire Armoured or Tape Armoured type depending upon the presence or absence of Armour.
5) HT / LT Aerial Bunched Cables


Polyvinyl chloride Cables useful properties are :-

They are commonly abbreviated as PVC, insulated cables are widely used in various fields.
PVC's Cables are generally have following Properties:-
1. Low cost
2. Chemical resistance
3. High tensile strength
4. Better flexibility

For, electric cables the PVC is mixed up with plasticizers.
Low voltage copper conductor PVC cables are extensively used for domestic home appliances wiring, house wiring and internal wiring for lighting circuits in factories, power supply for office automation, in control.
PVC CABLES
1) Power Cables upto 1.1 KV
2) Multicore Cables upto 61 Cores
3) Sheilded instrumentation Cables
4) FRLS / FR / HR / Fire Survival Cable 

-> Electrical, mechanical, weather ability contrast table:
Properties
XLPE
PVC
1. Chemical Structure
Thermoset, pure Hydrocarbon. Non-Polar C-C or Si-o-Bonds
Thermoplastic Polar Rotosenated. C. Ci. Bond
2. Polymer Structure
Partial Crystalline
Amorphous
3. Long-term Working Temperature
90
70
4. Emergency overload
130
90
5. Highest working temperature of short circuit
250
160
6. Carrying capacity(A)
1.25a
1a
7. Dielectric constant(20,60Hz)
2.3
8
8. Cable Installation Job 
Easy due to less Wt, less Diam and Less Bending radius.
 Not Easy Like XLPE
9. Service life (year)
30
20
10. Cable diameter
0.92D
D
11. Volume resistivity(Ω·m)
1016~1018
1010-1013
12. Tensile strength(Mpa)
23
20
13. Thermal Resistivity   (Deg C/cm/watt)    
7.4
730
14. Thermal conductivity(W/m·K)
0.48
0.15
15. Dielectric loss tangent (20,60Hz)
0.0002-0.0003
0.04-0.12
16. Elongation (%)
450-600
100-400
17. The breakdown field strength (MV/m)
35-50
20-35
18.Power Factor at 20DegC X1013
-90
80
19. Low Temperature   Brittleness Deg. C
Excellent
-15
20. Moisture Penetration   Resistance
Excellent
Good
21. Water quantity (%)
<0.01
0.8
22. Oxygen index
18
30
23. Toxicity index
1.77
15.01
24. Brittleness temperature
-60
-40
25. Softening temperature
120
120
26. Resistance to acid and alkali, and climate
best
good ~ best
27. Whether containing halogen
do not contain
containing
28. Moisture Penetration   Resistance
Excellent
Good
29. Oil Resistance
Excellent
Fair
30. Solvent Resistance
Excellent
Poor
31. Acid Resistance
Excellent
Fair
32. Alkali Resistance
Excellent
Good
33. Standard
BS 5467
BS 6346

-> Toxicity index comparison table:
Gas
Gas concentration CQ(ppm)
Dangerous concentrations CQ (ppm)
Polyvinyl chloride (PVC)
Crosslinked polyethylene (XLPE)
CO
5525
1971
4000
CO2
46300
125400
100000
HCL
6173
0
500
NO2
1.5
3.6
250
SO2
3.25
1.8
400
Toxicity index
15.01
1.77


Summary: cross linked polyethylene insulation cable in the electrical performance, heat resistance, physical and mechanical properties, resistance to climate and toxicity are better than PVC insulated cable.

Reasons Why XLPE is Popular
Here are five reasons why XLPE are popular than standard wires available in the market.
  1. Excellent Mechanical and Physical Properties: XLPE has high thermal resistance and higher melting point than most standard cables found in the market. These cables possess low tan delta, high initial dielectric strength, low dielectric strength, and improved mechanical properties at high temperature. Also, XLPE resists moisture, UV light, oxidation, environmental stress, stress cracking, and rupture.
  2. Lightweight: The XLPE wire is lighter than other standard wires with a paper or lead insulation. That’s why it is more convenient to install and transport. XLPE wires are largely used in the construction industry because they reduce transportation and installation costs.
  3. Easy to Maintain: XLPE wires require lesser maintenance, when compared to other standard cables. Also, they have easy jointing and termination procedures.
  4. Used for HT and LT Lines: XLPE wires can be used for both HT and LT lines.
  5. Flexibility: XLPE wires have multiple cores, which makes them highly flexible. This added flexibility contributes to smaller bending radius as well.



Recently XLVLDPE (Cross Linked Very Low Density Polyethylene) wires have been introduced to the market.  These wires have enhanced physical and mechanical properties than regular XLPE wires. The above-mentioned factors and XLVLPDE wires depict the rising popularity of XLPE wires in the market.