Medium Voltage Power Cables Catalogue - AEC Online

Table E.4
Derating factors for depths of laying for cables in ducts
Depth of laying
mt.
Single-core cables
Nominal conductor size
Three-core cables
0.50
0.60
0.80
1.00
1.25
1.50
1.75
2.00
2.50
3.00
≤ 185 mm 2 > 185 mm 2 1.03
1.04
1.02
1.00
0.98
0.96
0.95
0.94
0.93
0.91
0.90
1.05
1.03
1.00
0.97
0.95
0.93
0.92
0.91
0.89
0.88
1.02
1.00
0.99
0.97
0.96
0.95
0.94
0.93
0.92
Table E.5
Derating factors for soil thermal resistivities for direct buried single-core cables
Nominal area
Values of soil thermal resistivity ºC.m / Watt
of conductor
mm 2 0.7 0.8 0.9 1.0 1.5 2.0 2.5 3.0
25
35
50
70
95
120
150
185
240
300
400
500
630
800
1000
1.30
1.30
1.32
1.33
1.34
1.34
1.35
1.35
1.36
1.36
1.37
1.37
1.37
1.37
1.37
1.25
1.25
1.26
1.27
1.28
1.28
1.28
1.29
1.29
1.30
1.30
1.30
1.30
1.30
1.30
1.20
1.21
1.21
1.22
1.22
1.22
1.23
1.23
1.23
1.24
1.24
1.24
1.24
1.24
1.24
1.16
1.16
1.16
1.17
1.18
1.18
1.18
1.18
1.18
1.19
1.19
1.19
1.19
1.19
1.19
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
0.89
0.89
0.89
0.89
0.89
0.88
0.88
0.88
0.88
0.88
0.88
0.88
0.88
0.88
0.88
0.81
0.81
0.81
0.81
0.80
0.80
0.80
0.80
0.80
0.80
0.79
0.79
0.79
0.79
0.79
0.75
0.75
0.74
0.74
0.74
0.74
0.74
0.74
0.73
0.73
0.73
0.73
0.73
0.73
0.73