Cable size and current carrying capacity
Cable size and current carrying capacity for XLPE insulated cable, non-armored, Twin or multicore cable is as below:-
Conductor operating temperature is 90 degree Celsius
Ambient temperature: 30 degree Celsius.
Cable size and current carrying capacity for XLPE insulated, Armored, Twin or multicore cable is as below:-
Conductor operating temperature is 90 degree Celsius
Ambient temperature: 30 degree Celsius. For air and 20 degree Celsius for ground for installations require to comply with BS: 7671
Correction factors:-
For Ambient temperature:
Ambient temperature in degree Celsius | Correction Factor |
25 | 1.02 |
30 | 1.00 |
35 | 0.96 |
40 | 0.91 |
45 | 0.87 |
50 | 0.82 |
55 | 0.76 |
60 | 0.65 |
65 | 0.58 |
70 | 0.50 |
75 | 0.41 |
80 |
Ground Temperature
Ambient temperature in degree Celsius | Correction Factor |
10 | 1.07 |
15 | 1.04 |
20 | 1.00 |
25 | 0.96 |
30 | 0.93 |
35 | 0.89 |
40 | 0.85 |
45 | 0.80 |
50 | 0.76 |
55 | 0.71 |
60 | 0.65 |
65 | 0.60 |
70 | 0.53 |
75 | 0.46 |
80 | 0.38 |
Soil Resistivity
Thermal resistivity Km/W | Rating factor for cables buried in Ducts | Rating factor for direct buried cables |
0.5 | 1.28 | 1.88 |
0.8 | 1.20 | 1.62 |
1.0 | 1.18 | 1.50 |
1.5 | 1.10 | 1.28 |
2.0 | 1.05 | 1.12 |
2.5 | 1.00 | 1.00 |
3.0 | 0.96 | 0.90 |
For cable selection chart for motors visit:-
http://electrialstandards.blogspot.in/2015/10/cable-selection-chart-for-motors.html
http://electrialstandards.blogspot.in/2015/10/cable-selection-chart-for-motors.html
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