Medium Voltage Cables/Rating Factors for thermal resistivity/Cables installed in single way ducts


Cables installed in single way ducts

Rating factors for variation in thermal resistivity of Soil (average values)


Size of cables
sqmm
Soil thermal resistivity in K.m/W
0.8 0.9 1.0 1.5 2.0 2.5 3.0
Single core              
50 1.08 1.06 1.04 0.94 0.87 0.82 0.77
70 1.09 1.06 1.04 0.94 0.87 0.81 0.76
95 1.09 1.06 1.04 0.94 0.87 0.81 0.76
120 1.10 1.07 1.04 0.94 0.86 0.80 0.75
150 1.10 1.07 1.04 0.94 0.86 0.80 0.75
185 1.10 1.07 1.04 0.93 0.86 0.79 0.75
240 1.11 1.07 1.04 0.93 0.86 0.79 0.74
300 1.11 1.08 1.05 0.93 0.85 0.79 0.74
400 1.11 1.08 1.05 0.93 0.85 0.78 0.73
500 1.11 1.08 1.05 0.93 0.85 0.78 0.73
630 1.12 1.08 1.05 0.93 0.84 0.78 0.72
 
Mulitcore              
50 1.05 1.03 1.02 0.96 0.91 0.87 0.83
70 1.05 1.04 1.02 0.96 0.91 0.86 0.82
95 1.06 1.04 1.02 0.96 0.91 0.86 0.82
120 1.06 1.04 1.03 0.95 0.90 0.85 0.81
150 1.06 1.04 1.03 0.95 0.90 0.85 0.80
185 1.07 1.05 1.03 0.95 0.89 0.84 0.80
240 1.07 1.05 1.03 0.95 0.89 0.84 0.79
300 1.07 1.05 1.03 0.95 0.88 0.83 0.78
400 1.07 1.05 1.03 0.95 0.88 0.83 0.78