Conversion Factors for Medium Voltage Power Cables,
6-30 kV
Load rating for cables laid in ground
Load factor 0.7 and 1.0
Fundamental conditions*
Ground temperature
Thermal resistivity
Distance between cables or systems
Single conductor cables laid in triangular touching arrangement
Load factor 0.7
Type of insulation
Cable design
Nominal voltage
Number of cables or systems
2
4
6
8
10
PVC
Multi conductor cables
0.6/1 to 3.6/6 kV
0.86
0.71
0.64
0.60
0.57
3-conductor cables
to 6/10 kV
0.87
0.71
0.63
0.59
0.54
Single conductor cables
0.6/1 to 3.6/6 kV
0.85
0.70
0.63
0.59
0.56
Single conductor cables
to 6/10 kV
0.83
0.66
0.57
0.53
0.49
VPE
Multi conductor cables
0.6/1 to 18/30 kV
0.85
0.70
0.63
0.59
0.56
3-conductor cables
0.6/1 to 18/30 kV
0.85
0.70
0.63
0.58
0.56
Load factor 1.0
Type of insulation
Cable design
Nominal voltage
Number of cables or systems
1
2
4
6
8
10
PVC
Multi conductor cables
0.6/1 to 3.6/6 kV
0.81
0.66
0.52
0.46
0.43
0.40
3-conductor cables
to 6/10 kV
0.82
0.67
0.51
0.45
0.41
0.37
Single conductor cables
0.6/1 to 3.6/6 kV
0.79
0.65
0.51
0.46
0.42
0.40
Single conductor cables
to 6/10 kV
0.78
0.62
0.47
0.40
0.36
0.33
VPE
Multi conductor cables
0.6/1 to 18/30 kV
0.83
0.67
0.53
0.47
0.44
0.41
3-conductor cables
0.6/1 to 18/30 kV
0.81
0.66
0.52
0.47
0.43
0.41
Built-up of system:
for single conducors:
for multi conductor cables:
Conversion factors for multi conductor cables (≤ 5 conductors), Conductor cross-section from 1.5 to 10 mm²
Number of loaded conductors
Conversion factors for the values of 1.5 to 10 mm²
Ground
Air
5
0.7
0.75
7
0.6
0.65
10
0.5
0.55
14
0.45
0.5
19
0.4
0.45
24
0.35
0.4
40
0.3
0.35
61
0.25
0.3
* For other conditions e.g. ground temperature, grouping, load factor, thermal resistance, the rating factors should be calculated according to DIN VDE 0276 part 1000.
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