We build cables for life
16
RATING FACTORS FOR VARIATION IN THERMAL RESISITIVITY OF SOIL
TWIN OR MULTI-CORE CABLES LAID IN SINGLE-WAY DUCTS
Nominal Area of Conductor Sqmm
Thermal Resistivity of Soil in °C m/w
0.7
0.8
0.9
1.0
1.2
1.5
2.0
2.5
3.0
3.5
4.0
1.5/2.5
1.04
1.03
1.02
1.02
1.0
0.98
0.94
0.91
0.88
0.86
0.83
4
1.04
1.04
1.03
1.02
1.0
0.97
0.94
0.90
0.87
0.85
0.82
6
1.05
1.04
1.03
1.02
1.0
0.97
0.93
0.90
0.86
0.84
0.81
10
1.05
1.04
1.03
1.02
1.0
0.97
0.93
0.89
0.86
0.83
0.80
16
1.06
1.04
1.03
1.02
1.0
0.97
0.92
0.88
0.85
0.82
0.79
25
1.06
1.05
1.03
1.02
1.0
0.96
0.92
0.88
0.84
0.82
0.78
35
1.06
1.05
1.03
1.02
1.0
0.96
0.92
0.87
0.83
0.81
0.77
50
1.07
1.05
1.03
1.02
1.0
0.96
0.91
0.87
0.83
0.80
0.77
70
1.07
1.05
1.04
1.02
1.0
0.96
0.91
0.86
0.82
0.79
0.76
95
1.07
1.06
1.04
1.02
1.0
0.96
0.91
0.86
0.82
0.78
0.75
120
1.08
1.06
1.04
1.03
1.0
0.95
0.90
0.85
0.81
0.78
0.74
150
1.09
1.06
1.04
1.03
1.0
0.95
0.90
0.85
0.80
0.77
0.73
185
1.09
1.07
1.05
1.03
1.0
0.95
0.89
0.84
0.80
0.76
0.72
240
1.09
1.07
1.05
1.03
1.0
0.95
0.89
0.84
0.79
0.76
0.72
300/400
1.10
1.07
1.05
1.03
1.0
0.95
0.88
0.83
0.78
0.75
0.71