Technical Reference

Maximum resistance of conductor and armour for single-core cable having aluminum wire armour

Nominal cross sectional area of conductor Maximum resistance per km of cable at 20 °C
Copper conductor Aluminum conductor Aluminum wire armour
Cables with stranded copper conductor Cables with solid aluminum conductor
600/1000 V 1900/3300 V 600/1000 V 1900/3300 V
mm2 Ω Ω Ω Ω Ω Ω
50 0.387 0.641 1.3 0.75 1.4 0.79
70 0.268 0.443 0.75 0.67 0.84 0.73
95 0.193 0.32 0.67 0.61 0.75 0.67
120 0.153 0.253 0.61 0.42 0.69 0.47
150 0.124 0.206 0.42 0.39 0.47 0.43
185 0.0991 0.164 0.38 0.37 0.42 0.4
240 0.0754 0.125 0.34 0.34 0.38 0.37
300 0.0601 0.1 0.31 0.31 0.35 0.34
400 0.047 — 0.22 0.22 — —
500 0.0366 — 0.2 0.2 — —
630 0.0283 — 0.18 0.18 — —
800 0.0221 — 0.13 0.13 — —
1 000 0.0176 — 0.12 0.12 — —

Maximum resistance of conductor and armour for two-, three-, four- and five-core cables having wire armour

1) With stranded copper conductor

Nominal cross sectional area of conductor Maximum resistance per km of cable at 20 °C
Copper conductor Aluminum conductor Steel wire armour
Cables with stranded copper conductors
Two-core Three-core Four-core Five-core
600/1000 V 600/1000 V 1900/3300 V 600/1000 V 600/1000 V
mm2 Ω Ω Ω Ω Ω Ω Ω
1.5 12.1 — 10.2 9.5 — 8.8 8.2
2.5 7.41 — 8.8 8.2 — 7.7 6.8
4 4.61 — 7.9 7.5 — 6.8 6.2
6 3.08 — 7 6.7 — 4.3 3.9
10 1.83 — 6 4 — 3.7 3.4
16 1.15 1.91 3.7 3.5 1.9 3.1 2.2
25 0.727 1.2 3.7 2.5 1.7 2.0 2.3 1.8
35 0.524 0.868 2.6 2.3 1.8 — 1.6
50 0.387 0.641 2.3 2 1.3 1.8 1.1
70 0.268 0.443 2 1.8 1.2 1.2 0.94
95 0.193 0.32 1.4 1.3 1.1 1.1 —
120 0.153 0.253 1.3 1.2 0.76 0.76 —
150 0.124 0.206 1.2 0.78 0.71 0.68 —
185 0.099 1 0.164 0.82 0.71 0.65 0.61 —
240 0.075 4 0.125 0.73 0.63 0.59 0.54 —
300 0.060 1 0.1 0.67 0.58 0.55 0.49 —
400 0.047 0 — 0.59 0.52 0.5 0.35 —

2) With solid aluminum conductor

Nominal cross-sectional area of conductor Maximum resistance per km of cable at 20 °C
Copper conductor Aluminum conductor Steel wire armour
Cables with solid aluminum conductors
Two-core Three-core Four-core
600/1000 V 600/1000 V 1900/3300 V 600/ 1000 V
mm2 Ω Ω Ω Ω Ω Ω
1.5 12.1 — — — — —
2.5 7.41 — — — — —
4 4.61 — — — — —
6 3.08 — — — — —
10 1.83 — — — — —
16 1.15 1.91 4 3.8 2 3.4
25 0.727 1.2 4.1 2.7 1.9 2.4
35 0.524 0.868 2.9 2.5 1.9 2.2
50 0.387 0.641 2.6 2.2 1.4 1.9
70 0.268 0.443 2.3 1.9 1.3 1.3
95 0.193 0.32 1.6 1.4 1.2 1.2
120 0.153 0.253 — 1.2 0.82 0.82
150 0.124 0.206 — 0.86 0.76 0.74
185 0.099 1 0.164 — 0.76 0.71 0.67
240 0.075 4 0.125 — 0.68 0.64 0.59
300 0.060 1 0.1 — 0.63 0.59 0.54
400 0.047 0 — — — — —

Electrical Properties(600/1000 V)

1) Single core with copper conductor

Nominal area of conductor Single Core Stranded Copper Conductors
Current Ratings Approximate voltage drop per ampereper metre
Direct in ground In singleway ducts Installed in air Ground Duct Air
mm² amps amps amps mV mV mV
50 235 235 222 0.87 0.93 0.87
70 290 280 285 0.62 0.70 0.62
95 345 330 346 0.47 0.56 0.47
120 390 370 402 0.39 0.48 0.39
150 435 405 463 0.33 0.43 0.33
185 490 440 529 0.28 0.39 0.28
240 560 500 625 0.24 0.35 0.24
300 630 550 720 0.21 0.32 0.21
400 700 580 815 0.20 0.30 0.20
500 770 620 918 0.18 0.28 0.18
630 840 670 1027 0.17 0.26 0.17
800 888 692 1119 0.17 0.25 0.17
1000 942 735 1214 0.16 0.24 0.16

1) Single core with aluminum conductor

Nominal area of conductor Single Core Aluminum Conductors
Current Ratings Approximate voltage drop per ampereper metre
Direct in ground In singleway ducts Installed in air Ground Duct Air
mm² amps amps amps mV mV mV
50 175 180 162 1.40 1.60 1.40
70 220 220 207 0.98 1.00 0.98
95 260 260 252 0.72 0.79 0.74
120 295 295 292 0.58 0.66 0.60
150 330 330 337 0.48 0.57 0.49
185 375 365 391 0.39 0.49 0.41
240 435 410 465 0.31 0.42 0.34
300 490 455 540 0.27 0.38 0.29
400 540 480 625 0.35 0.38 0.25
500 580 510 714 0.31 0.35 0.22
630 630 540 801 0.28 0.32 0.20

2) Two cores with copper conductor

Nominal area of conductor Two Cores Stranded Copper Conductors
Current Ratings Approximate voltage drop per ampere per metre
Direct in ground In single way ducts Installed in air Ground Duct Air
mm² amps amps amps mV mV mV
16* 140 115 115 2.9 2.9 2.9
25* 180 145 152 1.9 1.9 1.9
35* 215 175 188 1.3 1.3 1.3
50 255 210 228 1.0 1.0 1.0
70 315 260 291 0.7 0.7 0.7

2) Two cores with aluminum conductor

Nominal area of conductor Two Cores Aluminum Conductors
Current Ratings Approximate voltage drop per ampere per metre
Direct in ground In single way ducts Installed in air Ground Duct Air
mm² amps amps amps mV mV mV
25* 135 110 112 3.1 3.1 3.1
35* 165 130 138 2.2 2.2 2.2
50 195 155 166 1.7 1.7 1.7
70 240 195 211 1.1 1.1 1.1
95 288 237 254 0.8 0.8 0.8

3) Three cores with copper conductor

Nominal area of conductor Three Cores Stranded Copper Conductors
Current Ratings Approximate voltage drop per ampereper metre
Direct in ground In singleway ducts Installed in air Ground Duct Air
mm² amps amps amps mV mV mV
16 115 94 99 2.5 2.5 2.5
25 150 125 131 1.7 1.7 1.7
35 180 150 162 1.2 1.2 1.2
50 215 175 197 0.9 0.9 0.9
70 265 215 251 0.6 0.6 0.6
95 315 260 304 0.5 0.5 0.5
120 360 300 353 0.4 0.4 0.4
150 405 335 406 0.3 0.3 0.3
185 460 380 463 0.3 0.3 0.3
240 530 440 546 0.2 0.2 0.2
300 590 495 628 0.2 0.2 0.2
400 667 570 728 0.2 0.2 0.2

3) Three cores with aluminum conductor

Nominal area of conductor Three Cores Aluminum Conductors
Current Ratings Approximate voltage drop per ampereper metre
Direct in ground In singleway ducts Installed in air Ground Duct Air
mm² amps amps amps mV mV mV
16 89 72 74 4.2 4.2 4.2
25 115 94 98 2.7 2.7 2.7
35 135 110 120 1.9 1.9 1.9
50 165 135 145 1.4 1.4 1.4
70 200 165 185 1.0 1.0 1.0
95 240 200 224 0.7 0.7 0.7
120 275 230 264 0.6 0.6 0.6
150 310 255 305 0.5 0.5 0.5
185 350 295 350 0.4 0.4 0.4
240 410 340 418 0.3 0.3 0.3
300 460 385 488 0.3 0.3 0.3
400 520 443 562 0.2 0.2 0.2

4) Four cores with copper conductor

Nominal area of conductor Four Cores Stranded Copper Conductors
Current Ratings Approximate voltage drop per ampereper metre
Direct in ground In singleway ducts Installed in air Ground Duct Air
mm² amps amps amps mV mV mV
16 115 94 99 2.5 2.5 2.5
25 150 125 131 1.7 1.7 1.7
35 180 150 162 1.2 1.2 1.2
50 215 175 197 0.9 0.9 0.9
70 265 215 251 0.6 0.6 0.6
95 315 260 304 0.5 0.5 0.5
120 360 300 353 0.4 0.4 0.4
150 405 335 406 0.3 0.3 0.3
185 460 380 463 0.3 0.3 0.3
240 530 440 546 0.2 0.2 0.2
300 590 495 628 0.2 0.2 0.2
400 667 570 728 0.2 0.2 0.2
500 720 605 800 0.2 0.2 0.2

4) Four cores with aluminum conductor

Nominal area of conductor Four Cores Aluminum Conductors
Current Ratings Approximate voltage drop per ampereper metre
Direct in ground In singleway ducts Installed in air Ground Duct Air
mm² amps amps amps mV mV mV
16 89 72 74 4.2 4.2 4.2
25 115 94 98 2.7 2.7 2.7
35 135 110 120 1.9 1.9 1.9
50 165 135 145 1.4 1.4 1.4
70 200 165 185 1.0 1.0 1.0
95 240 200 224 0.7 0.7 0.7
120 275 230 264 0.6 0.6 0.6
150 310 255 305 0.5 0.5 0.5
185 350 295 350 0.4 0.4 0.4
240 410 340 418 0.3 0.3 0.3
300 460 385 488 0.3 0.3 0.3
400 520 443 562 0.2 0.2 0.2
500 561 470 618 0.2 0.2 0.2

Electrical Properties(1900/3300 V)

Nominal area of conductor Single Core Stranded CopperConductors Nominal area of conductor Three Core Stranded CopperConductors
Current Ratings Current Ratings
Direct in ground In single wayducts Installed in air Direct in ground In single wayducts Installed in air
mm² amps amps amps mm² amps amps amps
50 222 219 228 16 114 96 106
70 271 264 285 25 147 124 142
95 324 310 350 35 175 147 168
120 366 342 407 50 207 174 202
150 409 376 463 70 254 214 255
185 460 414 528 95 304 257 312
240 528 464 623 120 345 293 361
300 589 506 710 150 387 328 410
400 651 535 808 185 436 371 471
500 720 579 915 240 502 428 554
630 789 624 1030 300 563 480 634
800 831 650 1119 - - - -
1000 880 689 1214 - - - -