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
area (mm^2 )

Single core

in trefoil

3and4

cores

Approximate armouring

resistance

Resistance

at 90◦C

(ohm/km)

Reactance at

50 Hz

(ohm/km)

Resistance

at 90◦C

(ohm/km)

Reactance

at 50 Hz

(ohm/km)

AWA at 80◦C

(ohm/km)

1-core

SWA at 80◦C

(ohm/km)

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
area (mm^2 )

Air Ducts Direct buried Notes

1.5 26 26 32

2.5 35 34 42

4474555

6595669

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 2530354045505560
Rating factorKairfor cables laid in air 1.0 0.96 0.92 0.88 0.84 0.79 0.73 0.68
Ground temperature◦C 10152025303540
Rating factorKgrdfor cables laid in the ground 1.03 1.0 0.97 0.93 0.89 0.86 0.82