Page 219 - Handbook of Electrical Engineering

CABLES, WIRES AND CABLE INSTALLATION PRACTICES 203

Table 9.16. Land based Installations. 600/1000 V. Cu/XLPE/PVC/AWA/PVC single core Cu/XLPE/PVC/
SWA/PVC 3 and 4 core
Nominal conductor Single core 3and4 Approximate armouring
2
area (mm ) in trefoil cores resistance
◦
◦
Resistance Reactance at Resistance Reactance AWA at 80 C SWA at 80 C
◦
◦
at 90 C 50 Hz at 90 C at 50 Hz (ohm/km) (ohm/km)
(ohm/km) (ohm/km) (ohm/km) (ohm/km) 1-core 3/4 core
1.5 15.4 0.103 11.40
2.5 9.45 0.101 9.48
4 5.88 0.0929 5.52
6 3.93 0.0885 4.92
10 2.33 0.0835 4.08
16 1.47 0.0815 2.64
25 0.927 0.0818 2.52
35 0.668 0.0771 2.28
50 0.494 0.104 0.494 0.0765 1.018 1.56
70 0.342 0.101 0.342 0.0754 0.919 1.44
95 0.246 0.0969 0.247 0.0727 0.795 1.176
120 0.196 0.0920 0.197 0.0723 0.559 0.852
150 0.160 0.0945 0.160 0.0728 0.509 0.780
185 0.128 0.0932 0.128 0.0730 0.460 0.708
240 0.0985 0.0902 0.0989 0.0722 0.410 0.624
300 0.0799 0.0883 0.0802 0.0717 0.385 0.564
400 0.0639 0.0886 0.0656 0.0715 0.286 0.408

Table 9.17. Land based installations. 600/1000 V. Cu/XLPE/PVC/SWA/PVC 3 and 4 cores
Nominal conductor Air Ducts Direct buried Notes
2
area (mm )
1.5 26 26 32
2.5 35 34 42
4 47 45 55
6 59 56 69
10 82 75 92
◦
16 107 96 119 Thermal resistivity of soil 1.2 Cm/W
25 140 124 152
◦
35 172 149 182 Ambient air temp. is 25 C
50 209 177 217 Depth of laying cables is 0.5 m
70 263 218 266
◦
95 324 263 319 Standard ground temp. is 15 C
◦
120 376 300 363 Conductor surface temp. is 90 C
150 430 338 406
185 495 382 458
240 584 442 529
300 666 496 592
400 766 570 667
◦
Ambient air temperature C 25 30 35 40 45 50 55 60
Rating factor K air for cables laid in air 1.0 0.96 0.92 0.88 0.84 0.79 0.73 0.68
◦
Ground temperature C 10 15 20 25 30 35 40
Rating factor K grd for cables laid in the ground 1.03 1.0 0.97 0.93 0.89 0.86 0.82