Page 217 - Handbook of Electrical Engineering

CABLES, WIRES AND CABLE INSTALLATION PRACTICES 201

Table 9.12. Land based installations. 600/1000 V. Cu/PVC/PVC/AWA/PVC single core

Nominal Air Air Ducts Direct buried Notes
conductor trefoil 3 trefoil
2
area (mm ) horizontally trefoil 3 3
spaced horizontally horizontally
touching spaced
50 193 247 193 203 193 202 Thermal resistivity of
◦
70 243 307 229 248 233 243 soil is 1.2 Cm/W
95 298 372 269 297 277 288 Ambient air
◦
120 347 429 302 337 315 326 temperature is 30 C
150 395 472 324 376 347 355 Depth of laying cables
185 452 528 356 423 386 393 is 0.5 m
240 532 606 398 485 441 443 Standard ground
◦
300 607 672 435 542 490 486 temperature is 15 C
400 690 719 460 600 533 516 Conductor surface
◦
temperature is 70 C
◦
Ambient air temperature C 25 30 35 40 45 50 55 60
Rating factor K air for cables 1.02 1.0 0.94 0.87 0.79 0.71 0.61 0.50
laid in air

Table 9.13. Land based installations. 600/1000 V. Cu/PVC/PVC/AWA/PVC single core Cu/PVC/PVC/SWA/
PVC 3 and 4 cores

Nominal conductor Single cores in trefoil 3 and 4 cores Approximate armouring
2
area (mm ) resistance
Resistance Reactance Resistance Reactance AWA SWA
◦
◦
◦
◦
at 70 C at50 Hz at70 C at50 Hz at80 C at 80 C
(ohm/km) (ohm/km) (ohm/km) (ohm/km) (ohms/km) (ohms/km)
1.5 14.451 0.104 2.39 11.40
2.5 8.868 0.101 1.99 9.48
4 5.518 0.099 1.16 5.52
6 3.688 0.094 1.03 4.92
10 2.186 0.090 0.857 4.08
16 1.380 0.087 0.554 2.64
25 0.870 0.084 0.529 2.52
35 0.627 0.081 0.479 2.28
50 0.464 0.112 0.464 0.081 0.328 1.56
70 0.321 0.107 0.321 0.079 0.302 1.44
95 0.232 0.103 0.232 0.077 0.247 1.176
120 0.184 0.103 0.184 0.076 0.179 0.852
150 0.150 0.101 0.150 0.076 0.164 0.780
185 0.121 0.099 0.121 0.076 0.149 0.708
240 0.0927 0.096 0.0929 0.075 0.131 0.624
300 0.0751 0.094 0.0752 0.074 0.118 0.564
400 0.0600 0.091 0.0604 0.074 0.0857 0.408