riyadh cables group of companies (rcgc), is a premier

RIYADH CABLES GROUP OF COMPANIES (RCGC), is a premier manufacture of quality Wires, Conductors and Cables with a wide range of products.

Our commitment to quality, professional outlook and dedicated service put us as one of the leading names in the Cables and Allied Manufacturing Industry in the Middle East and do enjoy a prominent slot in the “Top 100 companies in the Kingdom”.

RCGC, located in the Second Industrial City - Riyadh with a paid up capital ofS.R. 868 Million, backed by a dedicated work force of over 1500 consisting ofhigh calibre multinational professionals and with advanced production facilities sprawling over a complex admeasuring 260000 m is all poised for further expansion.

RIYADH CABLES GROUP OF COMPANIES with its steady growth, innovative approach and expertise are committed to maintain and enhance its reputation in the years ahead. We believe that our success to date will provide a springboard for further achievements in the future both in the domestic and export arena alike.

RCGC’s well defined Quality Assurance System adds to the infrastructure for the most reliable products and ensure its conformity strictly to National/Internaional standards and specific requirements of customers to reach all the corners of Domestic and Export Market.

Quality is our prime concern.

OUR RANGE OF PRODUCTION :Wire and Cable Wiring 450/750 Volts and 500 Volts.Special Electrical Wires.Low Voltage Cables 1 kV Copper and Aluminium, PVC and XLPE insulated, armoured, non-armoured and lead sheathed.Medium and High Voltage Cables up to 240 kV Aluminium and Copper, XLPE insulated, armoured, non-armoured and lead sheathed.Control Cables XLPE and PCV insulated, shielded and non-shielded, armoured, non-armoured and lead sheathed.Overhead Line Conductors and Aerial Cables:Copper, Aluminium, Aluminium Alloy, Plain, and AW, Steel Wire Reinforced for all voltages up to 500 kV (Bare Conductors).Telephone Cables.Copper Rods and PVC Granules for Cable insulation and sheath.

CURRENT CARRYING CAPACITY 0.6/1 kV

PAGE 1RIYADH CABLES L . V . E L E C T R I C A L G U I D E

INTRODUCTION

2

Cables having Uo = U/2 or Uo = U/ 3 may be used In all a.c. installations with rated voltages up to 1.2 kV , in all single-phase a.c. three -phase installations with rated voltages over 1.2 kV or 1 kV respectively, the neutral point of which is solidly earthed.

In all single-phase a.c. and three-phase installations with rated voltages over 1.2 kV or 1 kV respectively, the neutral point of which is not solidly earthed, if the duration of single line-to-earth fault does not exceed 8 hours and the duration of all line-to-earth faults occurring within a year does not exceed 125 hours. If compliance with this condition cannot be ensured the cable life shall be taken into regard and a cable with a higher rated voltage shall be chosen.

GUIDELINES FOR LOAD CAPACITYThe loading of the cable must be so limited that, at any point of the cable installation,all the heat produced in the conductors under set conditions can be safely dissipated to the ambient medium. Experience has shown that cables may be loaded as indicated in the tables. The values stated in Table no. 1 for cables laid in ground are based on standard service conditions mostly used in power systems of electricity boards.

Load Factor : 0.7Thermal resistivity of soil : 1.0 Km/W (moist area)

Ground temperature : 20 CNo. of cables / System : 1Laying depth : 0.7 meters



APPLICATIONSMAXIMUM CONTINUOUSLY

PERMISSIBLE SERVICE VOLTAGE

NominalVoltage

Maximum Continuously Permissible Service Voltage For

1-Phase systemswith both lineconductors

isolated

one lineconductorearthed

3-Phase systemsUo / U

kVkV kVkV

1.48.31420

0.74.1710

1.27.212

17.5

0.6 / 13.5 / 66 / 10

8.7 / 15

The current values apply to cables laid direct in the ground, bedded in sand if necessary and covered with table tiles, the cables route including only a limited number of cables pipes none of them being above 6 meters in length. It is also assumed that any pole mounted distribution points with be shielded as far as possible from direct sunlight.

For overhead installations as shown in Table No. 2, continuous load factor 1.0 is permissible. The values given apply to cables laid in air at 30 C. it is assumed here that heat dissipation by convection and radiation will not be impeded, that the ambient temperature will not rise and that there are no external heat sources. These conditions can be taken as met if :

The cable is laid at least 2 cm form the nearest wall, floor or ceiling.

The spacing between adjacent cables is at least twice the cable diameter.

Cables being laid above each other have a vertical separation of at least twice the cable diameter, the cable systems are at least 30 cm.

The rise in ambient temperature due to the dissipating heat is taken into consideration or adequate space and ventilation is provided.

The leading ampacities determined according to IEC publication 287 or CENELEC 64 will be identical. They are based on the following figures for the thermal resistivity of the insulating materials.

PVC : 6.0 Km/W

XLPE : 3.5 Km/W

We also hold at your disposal computerized calculations for the most varied working conditions and can determine the maximum permissible load currents for almost any practical service condition.





BASED ON DIN 57 298 PART 2 VDE 0298 PART 2TABLE 1 CURRENT RATING FOR CABLE INSTALLED IN GROUND = 0.6 / 1 KV

1

Insulation

2 3 4 5 6 7 8 9 10 11 12 13 14

Cable Type

Norm

Max.conductortemperature

PVCN (A) YY ; N (A) YCWY

VDE 0271 / IEC 502

70 C 85 C 90 C

XLPEN (A) 2XY

VDE 0272 / IEC 502

arrangement

Coppermm

Ampere

107137165195239287326366414481542624698791

1.5 40 32 26 - - 44 28 32 39 48 30 32 392.5 54 42 34 - - 58 37 43 51 63 40 43 514 70 54 44 - - 76 48 55 66 82 52 55 666 90 68 56 - - 96 60 68 82 103 64 68 82

10 122 90 75 - - 129 80 90 109 137 86 90 10916 160 116 98 127 168 104 111 133 177 111 115 13925 206 - 128 163 217 135 143 171 229 143 149 17935 249 - 157 195 262 165 171 204 275 173 178 21350 296 - 185 230 311 195 203 240 327 205 211 25170 365 - 228 282 383 240 249 294 402 252 259 30795 438 - 275 336 460 289 298 351 482 303 310 366

120 499 - 313 382 524 329 339 399 550 346 352 416150 561 353 428 589 371 381 446 618 390 396 465-185 637 - 399 483 669 420 431 504 701 441 449 526240 743 - 464 561 781 487 501 585 819 511 521 610300 843 - 524 632 887 552 564 660 931 580 587 689400 986 600 730 1029 631 646 759 1073 663 669 788500 1125

-- - 823 1174 715 723 856 1223 - 748 889

630 - - - 933 - - 819 970 - - 848 1007

Aluminiummm

Ampere

254285323378427496562

25 - 99 - - 177 105 - - 177 111 - -35 192 118 127 151 202 125 132 157 212 132 137 16450 229 142 151 179 241 149 157 187 253 157 163 16570 282 176 186 218 296 185 193 228 311 195 201 23895 339 211 223 261 356 222 231 272 374 233 240 284

120 388 242 297 407 254 264 310 427 266 274 323150 435 270 332 457 284 296 346 479 299 308 361185 494 308 376 518 324 336 392 543 340 350 408240 578 363 437 607 382 393 456 637 401 408 476300 654 412 494 678 433 444 515 721 455 462 537400 765 475 572 798 500 513 594 832 526 531 616500 873 - 649 911 - 581 674 949 - 601 699

Table forf 1

Group 2

Ratingf 2

Factor

3 3 3 3 3 3 3 3 3 3 3 3 3

8 9 8 5/6 7 8 8 5/6 7 8 8 5/6 7

3) For N (A) YCWY only column 2 to 4.4) Current rating in d.c.6) Three phase current.

2

2

4) 6) 4) 6)

3



CURRENT RATING FOR L.V. WIRE ARMOURED CABLES INSTALLED IN GROUND

1

Insulation

2 3 4 5 6 7 8 9 10

Maximum ConductorTemperature

PVC

Arrangement

Coppermm

Ampere

70 C 85 C

2

90 C

XLPE

2535507095

120150185240300400500630

130159187230276313351394453505571

--

141165195239286322360404463508572624668

161193227275323357391429476521549579644

137167197242290329369414476532600659

-

147171203249297335375421482529592647692

169201236286338373407448497544571602670

145175207254304346388435499559631

--

153178211259309348390438502550613669716

177210247299352388425467518568593625695

Aluminiummm 2

2535507095

120150185240300400500

100119143177212242269304355397452

-

-127151186222251281315364400454502

-149176212251277303334371407430456

107127151187223254283320373417476

-

-132157193230261291328378416470519

-155184222261289316348387424447474

113134159197234266298335392439500

-

-137163201239270303341393433486537

-162192232273302329362404443463492

Ampere

Table forf1

Group 2

Notes:1) Single core cables are aluminum wire armoured.2) Aluminium wire armour is bonded at both ends.3) Values of steel wire armoured cables may safely be applied to steel tape-armoured cables.4) When cables are arranged in flat formation they are spaced by one cable diameter.

3 3 3 3 3 3 3 3 3

Table forf2

Factor8 5/6 7 8 5/6 7 8 5/6 7



BASED ON DIN 57 298 PART 2 VDE 0298 PART 2TABLE 2 CURRENT RATING FOR CABLE INSTALLED IN AIR = 0.6 / 1 kV

1

Insulation

2 3 4 5 6 7 8 9 10 11 12 13 14

Cable Type

Norm

Max.conductortemperature

PVCN (A) YY ; N (A) YCWY

VDE 0271 / IEC 502

70 C 85 C 90 C

XLPEN (A) 2XY

VDE 0272 / IEC 502

arrangement

Coppermm

Ampere

89118145176224271314361412484549657749856

1.5 26 20 18,5 20 25 29 21 22 28 32 24 25 322.5 35 27 25 27 34 39 28 30 38 43 32 34 424 46 37 34 37 45 51 33 40 50 57 42 44 566 58 48 43 48 65 48 52 64 72 53 57 71

10 79 66 60 66 89 66 71 87 99 73 77 9616 105 89 80 118 88 95 115 131 96 102 12825 140 118 106 158 118 128 155 177 130 139 17335 174 145 131 196 145 157 190 218 160 170 21250 212 176 159 239 177 192 232 266 195 208 25870 269 224 202 303 224 244 294 338 247 265 32895 331 271 244 373 274 298 362 416 305 326 404

120 386 314 282 436 318 347 422 487 355 381 471150 442 324 500 365 399 484 559 407 438 541361185 511 412 371 579 420 459 560 648 469 507 626240 612 484 436 695 493 545 669 779 551 606 749300 707 - 481 804 559 623 771 902 638 697 864400 359 560 1064 653 736 917 1270 746 816 1018500 1000

-

- - 1123 - 841 1056 1246 - 933 1173630 - - -

5778

103137169206261321374428494590678817940

- - 966 1296 - - 1117 1362

Aluminiummm

Ampere

224281320378433523603

25 128 83 - - 132 91 - - 137 100 - -35 145 102 113 131 156 112 122 147 168 122 131 16350 176 124 138 160 191 135 149 180 206 147 161 20070 224 158 174 202 243 173 289 228 262 189 205 25495 271 190 210 249 297 211 231 281 323 232 253 313

120 314 220 291 345 245 270 328 377 270 296 366150 361 252 333 397 280 311 376 433 308 341 420185 412 289 384 457 323 357 435 502 357 395 486240 484 339 460 544 387 426 522 605 435 475 585300 548 377 530 623 439 490 602 699 501 548 675400 666 444 642 748 518 585 720 830 592 647 798500 776 - 744 871 - 676 835 966 - 749 926

Table forf )

Group

Factor 2)

10 10 10 10 10 10 10 10 10 10 10 10 10

12 12 12 11 11 12 12 11 11 12 12 11 11

1) For air temperature2) For group3) For N (A) YCWY onl;y columns 2 to 44) Current rating in d.c.5) To 240 mm according to CENELEC, see Publication6) Three phase current

2

2

4) 6) 4) 6)

5

1138

91113138174210274281320378

---

3



CURRENT RATING FOR L.V. WIRE ARMOURED CABLES INSTALLED IN AIR

1

Insulation

2 3 4 5 6 7 8 9 10

Maximum ConductorTemperature

PVC

Arrangement

Coppermm

Ampere

70 C 85 C

2

90 C

XLPE

2535507095

120150185240300400500630

110135164208248287330373435473544

--

122159190239287329371419484536624692747

141173211262316368401450512559647696786

122150183230279324372423492550634

--

133172207261315364410467545608699777843

159194237295356416453510581636726782895

135165201254311362415472549628725

--

144187224283345400451516606680775862975

178217264329398464507570650712806869941

Aluminiummm 2

2535507095

120150185240300400500

86105128162193224257291338371431

-

-124149186222256289326378423496557

-134164203245286312340399437508551

94116139178215249285325386432503

-

-134160209244283320363426478555624

-150184229277323352396453496570618

104126152194236275314359434493575

-

-144173219268310351402475535614692

-167205255308360393442508556632686

Ampere

Table forf1

Group 2

Notes:1) Single core cables are aluminum wire armoured.2) Aluminium wire armour is bonded at both ends.3) Values of steel wire armoured cables may safely be applied to steel tape-armoured cables.4) When cables are arranged in flat formation they are spaced by one cable diameter.

10 10 10 10 10 10 10 10 10

Table forf2

Factor10 11 11 12 11 11 12 11 11

1,29 1,26 1,22 1,15 1,09

1,27 1,23 1,19 1,13 1,06

1,25 1,21 1,17 1,10 1,03

1,23 1,18 1,14 1,08 1,01

1,13 1,11 1,08 1,04 1,00

1,11 1,08 1,06 1,01 0,97

1,08 1,06 1,03 0,99 0,94

1,06 1,03 1,00 0,96 0,91

0,99 0,98 0,97 0,95 0,93

0,96 0,95 0,94 0,92 0,89

0,93 0,92 0,91 0,88 0,86

0,90 0,89 0,87 0,85 0,83

0,86

0,83

0,79

0,76

5

10

15

20

1,03 1,00 0,97 0,93 0,88 0,87 0,85 0,84 0,82 0,79 0,7225

0,94 0,89 0,85 0,84 0,82 0,80 0,78 0,76 0,6830

0,77 0,74 0,72 0,6335

0,5940

TABLE 3 RATING FACTOR FOR CABLES INSTALLED IN GROUND

5 64321

Ground thermal resistivity C.m/W

0,7 1,0 1,5 2,5

load factor load factor load factor loadfactor

Max. conductortemperature

AmbientTemperature

0,50 0,60 0,70 0,85 1,00

1,24 1,12 1,18 1,13 1,07

1,23 1,19 1,16 1,11 1,05

1,21 1,17 1,14 1,08 1,03

1,19 1,15 1,12 1,06 1,00

0,50 0,60 0,70 0,85 1,00

1,11 1,09 1,07 1,03 1,00

1,09 1,07 1,05 1,01 0,98

1,07 1,05 1,02 1,99 0,95

1,05 1,02 1,00 1,96 0,93

0,50 0,60 0,70 0,85 1,00

0,99 0,98 0,97 0,96 0,94

0,97 0,96 0,95 0,93 0,91

0,95 0,93 0,92 0,91 0,89

0,92 0,91 0,90 0,88 0,86

0,5-1,00

0,89

0,86

0,84

0,81

CC

5

10

15

20

1,02 1,00 0,98 0,94 0,90 0,90 0,88 0,87 0,85 0,84 0,7825

0,95 0,91 0,88 0,87 0,86 0,84 0,83 0,81 0,7530

0,82 0,80 0,78 0,7235

0,6840

90

1,27 1,23 1,20 1,14 1,08

1,25 1,21 1,17 1,12 1,06

1,23 1,19 1,15 1,09 1,03

1,20 1,17 1,13 1,07 1,01

1,12 1,10 1,07 1,04 1,00

1,10 1,07 1,05 1,01 0,97

1,07 1,05 1,03 1,99 0,95

1,05 1,03 1,00 1,97 0,92

0,99 0,98 0,97 0,95 0,93

0,97 0,95 0,94 0,92 0,91

0,94 0,93 0,92 0,90 0,88

0,91 0,90 0,89 0,87 0,85

0,88

0,85

0,82

0,78

5

10

15

20

1,03 1,00 0,97 0,93 0,89 0,88 0,87 0,86 0,84 0,82 0,7525

0,95 0,91 0,86 0,85 0,84 0,83 0,81 0,78 0,7230

0,80 0,77 0,75 0,6835

0,6440

85

70



321

CONSTRUC-TION

number ofsystem 0,7 1,0 1,5 2,5

load factor

4 5 6

load factor


load factor load factorXLPE cable

0,6

1,04

0,90

0,80

0,75

0,71

0,68

0,64

0,61

0,7

0,99

0,84

0,74

0,69

0,65

0,63

0,59

0,56

0,5

1,09

0,97

0,88

0,83

0,79

0,76

0,72

0,69

0,6

1,05

0,91

0,82

0,76

0,72

0,69

0,65

0,62

0,7

1,00

0,85

0,75

0,70

0,66

0,63

0,59

0,56

0,5

1,11

0,98

0,89

0,84

0,80

0,77

0,72

0,69

0,6

1,07

0,92

0,82

0,77

0,73

0,70

0,65

0,62

0,7

1,01

0.86

0,76

0,70

0,66

0,63

0,59

0,56

0,5

1,13

1,00

0,90

0,85

0,80

0,77

0,73

0,70

0.6

1.09

0.94

0.83

0.78

0.73

0.70

0.66

0.63

0.7

1.03

0.87

0.76

0.71

0.67

0.64

0.59

0.57

0,5

1,17

1,02

0,92

0,82

0,81

0,78

0,74

0.70

1

2

3

4

5

6

8

10

load factor load factor load factor load factorPVC Cable

0,6

1,02

0,89

0,79

0,75

0,71

0,68

0,64

0,61

0,7

0,99

0,84

0,74

0,69

0,65

0,62

0,58

0,55

0,5

1,01

0,94

0,86

0,82

0,78

0,75

0,71

0,68

0,6

1,05

0,91

0,81

0,76

0,72

0,69

0,65

0,62

0,7

1,00

0,85

0,75

0,70

0,66

0,63

0,59

0,56

0,5

1,04

0,97

0,89

0,84

0,80

0,77

0,72

0,69

0,6

1,06

0,92

0,83

0,77

0,73

0,70

0,65

0,62

0,7

1,01

0,86

0,76

0,71

0,66

0,64

0,59

0,56

0,5

1,07

0,99

0,90

0,85

0,80

0,77

0,73

0,69

0,6

1,08

0,93

0,83

0,78

0,73

0,70

0,66

0,63

0,7

1,01

0,87

0,77

0,71

0,67

0,64

0,60

0,57

0,5

1,11

1,01

0,91

0,86

0,81

0,78

0,73

0,70

1

2

3

4

5

6

8

10

load factor load factor load factor load factorAll

1,0

0,87

0,71

0,61

0,56

0,52

0,50

0,46

0,44

0,85

0,93

0,77

0,67

0,62

0,58

0,55

0,51

0,49

1,0

0,87

0,71

0,61

0,56

0,52

0,50

0,46

0,44

0,85

0,93

0,77

0,67

0,62

0,58

0,55

0,52

0,49

1,0

0,87

0,71

0,61

0,56

0,52

0,50

0,46

0,44

0,85

0,94

0,77

0,68

0,62

0,58

0,56

0,52\

0,49

1,0

0,87

0,71

0,61

0,56

0,52

0,50

0,46

0,44

0,85

0,94

0,78

0,68

0,63

0,59

0,56

0,52

0,49

1

2

3

4

5

6

8

10

TABLE 5 f2 GROUP FACTOR FOR CABLEINSTALLED IN GROUND TREFOIL FORMATION

7 cm



321

CONSTRUC-TION


4 5 6


321

CONSTRUC-TION


4 5 6


321

CONSTRUC-TION


load factor

4 5 6

load factor



0,6

1,04

0,94

0,87

0,84

0,80

0,79

0,76

0,74

0,7

0,99

0,89

0,81

0,78

0,74

0,72

0,70

0,68

0,5

1,09

1,01

0,94

0,91

0,88

0,86

0,83

0,81

0,6

1,05

0,95

0,88

0,84

0,81

0,79

0,76

0,74

0,7

1,00

0,89

0,82

0,78

0,75

0,73

0,70

0,68

0,5

1,11

1,02

0,95

0,92

0,89

0,87

0,84

0,82

0,6

1,07

0,97

0,89

0,85

0,82

0,80

0,77

0,75

0,7

1,01

0,90

0,82

0,79

0,75

0,73

0,70

0,68

0,5

1,13

1,04

0,97

0,93

0,90

0,88

0,85

0,83

0,6

1,09

0,98

0,90

0,86

0,83

0,81

0,78

0,76

0,7

1,03

0,91

0,83

0,79

0,76

0,74

0,71

0,69

0,5

1,17

1,06

0,99

0,95

0,91

0,89

0,86

0,84

1

2

3

4

5

6

8

10

321number of

system 0,7 1,0 1,5 2,5

load factor

4 5 6

load factor load factor load factorPVC Cable

0,6

1,02

0,95

0,88

0,84

0,81

0,79

0,76

0,75

0,7

0,99

0,89

0,82

0,78

0,75

0,73

0,70

0,69

0,5

1,01

0,97

0,94

0,91

0,88

0,86

0,83

0,82

0,6

1,05

0,96

0,88

0,85

0,82

0,80

0,77

0,75

0,7

1,00

0,90

0,82

0,79

0,76

0,74

0,71

0,69

0,5

1,04

1,00

0,97

0,92

0,89

0,87

0,84

0,82

0,6

1,06

0,97

0,89

0,86

0,82

0,81

0,78

0,76

0,7

1,01

0,91

0,83

0,79

0,76

0,74

0,71

0,69

0,5

1,07

1,03

0,97

0,93

0,90

0,88

0,85

0,83

0,6

1,08

0,98

0,90

0,87

0,83

0,81

0,78

0,76

0,7

1,01

0,92

0,84

0,80

0,77

0,75

0,72

0,70

0,5

1,11

1,06

0,98

0,95

0,91

0,89

0,86

0,84

1

2

3

4

5

6

8

10

load factor load factor load factor load factor

1,0

0,87

0,75

0,67

0,64

0,60

0,59

0,56

0,54

0,85

0,93

0,82

0,74

0,70

0,67

0,65

0,62

0,60

1,0

0,87

0,75

0,67

0,64

0,60

0,59

0,56

0,54

0,85

0,93

0,82

0,74

0,70

0,67

0,65

0,62

0,60

1,0

0,87

0,75

0,67

0,64

0,60

0,59

0,56

0,54

0,85

0,94

0,82

0,74

0,70

0,67

0,65

0,62

0,61

1,0

0,87

0,75

0,67

0,64

0,60

0,59

0,56

0,54

0,85

0,94

0,83

0,74

0,71

0,67

0,65

0,62

0,61

1

2

3

4

5

6

8

10

TABLE 6 f2 GROUP FACTOR FOR CABLEINSTALLED IN GROUND TREFOIL FORMATION

All

25 cm




321number of

system 0,7 1,0 1,5 2,5

4 5 6Ground thermal resistivity C.m/W

321

CONSTRUC-TION


load factor

4 5 6

load factor



0,6

1,05

0,93

0,84

0,80

0,76

0,74

0,71

0,69

0,7

0,99

0,86

0,77

0,73

0,69

0,67

0,64

0,62

0,5

1,08

1,01

0,92

0,88

0,84

0,82

0,79

0,77

0,6

1,07

0,94

0,85

0,80

0,77

0,75

0,71

0,69

0,7

1,00

0,87

0,77

0,73

0,70

0,68

0,65

0,63

0,5

1,13

1,03

0,93

0,89

0,85

0,83

0,80

0,78

0,6

1,09

0,95

0,86

0,81

0,78

0,75

0,72

0,70

0,7

1,01

0.88

0,78

0,74

0,70

0,68

0,65

0,63

0,5

1,18

1,05

0,95

0,90

0,87

0,84

0,81

0,78

0,6

1,11

0,96

0,86

0,82

0,78

0,76

0,72

0,70

0,7

1,03

0,88

0,79

0,74

0,71

0,69

0,65

0,63

0,5

1,19

1,06

0,96

0,91

0,87

0,85

0,81

0.79

1

2

3

4

5

6

8

10

321number of

system 0,7 1,0 1,5 2,5

load factor

4 5 6

load factor load factor load factorPVC Cable

0,6

0,97

0,89

0,84

0,80

0,76

0,74

0,71

0,69

0,7

0,98

0,86

0,77

0,73

0,70

0,68

0,65

0,83

0,5

1,96

0,92

0,88

0,86

0,84

0,82

0,79

0,77

0,6

1,01

0,94

0,85

0,81

0,77

0,75

0,72

0,70

0,7

1,00

0,87

0,87

0,74

0,70

0,68

0,65

0,63

0,5

1,01

0,96

0,91

0,89

0,85

0,83

0,80

0,78

0,6

1,05

0,95

0,86

0,82

0,78

0,76

0,72

0,70

0,7

1,01

0,88

0,79

0,74

0,71

0,69

0,65

0,63

0,5

1,07

1,00

0,95

0,90

0,87

0,84

0,81

0,79

0,6

1,10

0,97

0,87

0,82

0,79

0,76

0,73

0,71

0,7

1,02

0,89

0,79

0,75

0,71

0,69

0,66

0,64

0,5

1,16

1,05

0,96

0,91

0,87

0,85

0,81

0,79

1

2

3

4

5

6

8

10


1,0

0,85

0,71

0,62

0,58

0,55

0,53

0,51

0,49

0,85

0,91

0,77

0,69

0,65

0,61

0,59

0,57

0,55

1,0

0,85

0,71

0,62

0,58

0,55

0,53

0,51

0,49

0,85

0,92

0,78

0,69

0,65

0,61

0,60

0,57

0,55

1,0

0,85

0,71

0,62

0,58

0,58

0,53

0,51

0,49

0,85

0,92

0,78

0,69

0,65

0,62

0,60

0,57

0,55

1,0

0,85

0,71

0,62

0,58

0,55

0,53

0,51

0,49

0,85

0,93

0,79

0,69

0,65

0,62

0,60

0,57

0,55

1

2

3

4

5

6

8

10

TABLE 7 f2 GROUP FACTOR SINGLE CORE CABLEINSTALLED IN GROUND FLAT FORMATION 7 cm




321number of

system 0,7 1,0 1,5 2,5

4 5 6Ground thermal resistivity C.m/W

321

CONSTRUC-TION


load factor

4 5 6

load factor



0,6

1,03

0,89

0,80

0,75

0,71

0,68

0,64

0,61

0,7

0,99

0,84

0,74

0,69

0,65

0,63

0,59

0,56

0,5

1,02

0,95

0,86

0,82

0,78

0,75

0,71

0,68

0,6

1,05

0,91

0,81

0,76

0,72

0,69

0,65

0,62

0,7

1,00

0,85

0,75

0,70

0,66

0,63

0,59

0,56

0,5

1,06

0,98

0,89

0,84

0,80

0,77

0,72

0,69

0,6

1,06

0,92

0,83

0,78

0,73

0,70

0,66

0,63

0,7

1,01

0.86

0,77

0,71

0,67

0,64

0,60

0,57

0,5

1,09

0,99

0,90

0,85

0,81

0,78

0,73

0,70

0.6

1.07

0.94

0.84

0.78

0.74

0.71

0.66

0.63

0.7

1.02

0.87

0.77

0.72

0.67

0.65

0.60

0.57

0,5

1,11

1,01

0,92

0,86

0,82

0,79

0,74

0.71

1

2

3

4

5

6

8

10


0,6

0,92

0,87

0,80

0,76

0,72

0,69

0,65

0,62

0,7

0,94

0,85

0,75

0,70

0,66

0,64

0,59

0,57

0,5

0,91

0,86

0,82

0,80

0,78

0,76

0,72

0,69

0,6

0,97

0,90

0,82

0,77

0,73

0,70

0,66

0,63

0,7

1,00

0,86

0,76

0,71

0,67

0,64

0,60

0,57

0,5

0,97

0,91

0,86

0,84

0,81

0,77

0,73

0,70

0,6

1,03

0,93

0,84

0,78

0,74

0,71

0,67

0,64

0,7

1,01

0,87

0,77

0,72

0,68

0,65

0,61

0,58

0,5

1,04

0,97

0,91

0,86

0,81

0,78

0,74

0,71

0,6

1,07

0,94

0,84

0,79

0,75

0,72

0,67

0,64

0,7

1,02

0,88

0,78

0,73

0,68

0,65

0,61

0,58

0,5

1,13

1,01

0,92

0,87

0,82

0,79

0,75

0,71

1

2

3

4

5

6

8

10


1,0

0,89

0,72

0,62

0,57

0,53

0,51

0,47

0,44

0,85

0,94

0,77

0,68

0,63

0,59

0,56

0,52

0,49

1,0

0,89

0,72

0,62

0,57

0,53

0,51

0,47

0,44

0,85

0,94

0,78

0,68

0,63

0,59

0,56

0,52

0,50

1,0

0,89

0,72

0,62

0,57

0,53

0,51

0,47

0,44

0,85

0,94

0,78

0,69

0,63

0,59

0,57

0,52

0,50

1,0

0,85

0,72

0,62

0,57

0,53

0,51

0,47

0,44

0,85

0,95

0,79

0,69

0,64

0,60

0,57

0,53

0,50

1

2

3

4

5

6

8

10

TABLE 8 f2 RATING FACTOR FOR THREE CORECABLE IN THE GROUND IN FLAT FORMATION 7 cm



321

CONSTRUC-TION


4 5 6


321

CONSTRUC-TION


4 5 6


321

CONSTRUC-TION


load factor

4 5 6

load factor


load factor load factor

0,6

0,91

0,85

0,79

0,76

0,76

0,73

0,69

0,66

0,7

0,93

0,85

0,78

0,74

0,70

0,67

0,63

0,60

0,5

0,90

0,85

0,80

0,77

0,75

0,73

0,70

0,73

0,6

0,99

0,92

0,86

0,81

0,77

0,74

0,70

0,67

0,7

1,00

0,89

0,80

0,75

0,71

0,68

0,64

0,61

0,5

0,98

0,93

0,87

0,83

0,84

0,81

0,77

0,74

0,6

1,04

0,95

0,86

0,82

0,77

0,74

0,70

0,67

0,7

1,03

0.90

0,80

0,75

0,71

0,68

0,64

0,61

0,5

1,05

0,98

0,93

0,89

0,85

0,82

0,77

0,74

0.6

1.09

0.96

0.87

0.82

0.78

0.75

0.71

0.67

0.7

1.04

0.90

0.81

0.76

0.72

0.69

0.64

0.61

0,5

1,14

1,03

0,95

0,90

0,86

0,83

0,78

0.75

1

2

3

4

5

6

8

10


1,0

0,91

0,76

0,66

0,61

0,57

0,55

0,51

0,48

0,85

0,96

0,81

0,72

0,67

0,63

0,60

0,56

0,53

1,0

0,91

0,76

0,66

0,61

0,57

0,55

0,51

0,48

0,85

0,96

0,82

0,72

0,67

0,63

0,60

0,56

0,54

1,0

0,91

0,76

0,66

0,61

0,57

0,55

0,51

0,48

0,85

0,97

0,82

0,73

0,68

0,63

0,61

0,57

0,54

1,0

0,91

0,76

0,66

0,61

0,57

0,55

0,51

0,48

0,85

0,97

0,82

0,73

0,68

0,64

0,61

0,57

0,54

1

2

3

4

5

6

8

10

TABLE 9 GROUP FACTOR f2 FOR CABLEINSTALLED IN GROUND FLAT FORMATION

TABLE 10 RATING FACTOR FOR DIFFERENT AIR TEMPERATURE

12 131110987654321

CONSTRUC-TION

conductortemp

Ambient temperature C

55 60504540353025201510

C - - - - - - - - - - -

XLPE Cable 90 0,76 0,710,820,870,910,961,01,041,081,121,15

PVC Cable 85 0,68 0,600,760,830,890,951,01,051,101,141,18

PVC Cable 70 0,61 0,500,710,790,870,941,01,071,121,171,22

7 cm

321

CONSTRUC-TION


4 5 6


PVC Cable

1) 2 & 3 core cable in one phase and in d.c. system



DIN 57 298 PART 2 VDE 0298 PART 2TABLE 11 GROUP FACTOR F2 FOR CABLE INSTALLED ON CABLE TRAY

ARRANGED ON

STRUCTURE OR ON

THE WALL

GROUP FACTOR

No. ofCables

2 31

0.91 0.980.94

Cable spacing = d. cable diameterCable to wall > 2 cm

No. ofCables

Cable installation

1 2 3

0.92 0.98 0.88

laid on the ground

LAID ON TROUGHS(RESTRICTED AIRCIRCULATION)

No. ofTroughs

0.92 0.89 0.881

0.87

0.84

0.82

0.84

0.82

0.80

0.83

0.81

0.79

2

3

6

LAID ON CABLE RACKS

No. ofRacks

1.00 0.97 0.961

0.97

0.96

0.94

0.94

0.93

0.91

0.93

0.92

0.90

2

3

6

> 2 cm

> 2 cm

> 20

cm

dd

d

d

> 2 cm

> 20

cm

d

d

d

> 2 cm

d



DIN 57 298 PART 2 VDE 0298 PART 2TABLE 11 (CONTINUED)

GROUP FACTOR

2 31

0.86 0.840.89

No. oftrefoil

on cableracks

CABLE INSTALLATION

1 2 3

0.95 0.90 0.88

laid on the ground


No. ofTroughs

0.95 0.90 0.881

0.90

0.88

0.86

0.85

0.83

0.81

0.83

0.81

0.79

2

3

6

LAID ON CABLE RACKS

No. ofRacks

1.00 0.98 0.961

1.00

1.00

1.00

0.95

0.94

0.93

0.93

0.92

0.90

2

3

6

No. of trefoil

formation

GROUP factor can be

considered = 1

> 2 cm

> 2 cm

> 20

cm

2d

2d

2d

2d

> 2 cm

> 20

cm

2d 2d

2d

> 2 cm

> 20

cm

4d 2d

Cable spacing = d, cable diameterCable to wall > 2 CM



DIN 57 298 PART 2 VDE 0298 PART 2TABLE 12 GROUP FACTOR F2 FOR CABLE INSTALLED ON CABLE TRAY


CABLE INSTALLATION

1 3 6

laid on the ground


No. ofTroughs

0.95 0.90 0.88

0.90

0.88

0.86

0.85

0.83

0.81

0.83

0.81

0.79

1

2

3

6

LAID ON CABLE RACKS

GROUP factor can be

considered = 1

No. of cable sideby side 2 9

0.95 0.90 0.88 0.85 0.84

0.85

0.81

0.79

0.77

0.84

0.80

0.78

0.76

No. ofRacks

1.00 0.98 0.96

1.00

1.00

1.00

0.95

0.94

0.93

0.93

0.92

0.90

1

2

3

6

0.93

0.90

0.89

0.87

0.92

0.89

0.88

0.86

1 3 6No. of CABLES 2 9

ARRANGED ON

STRUCTURE OR

ON THE WALL

1.00 0.93 0.90 0.87 0.86

> 2 cm

> 2 cm

> 20

cm

dd

d

d

> 2 cm

> 20

cm

d

d

> 2 cm

d

d

> 2 cm

d

2d



DIN 57 298 PART 2 VDE 0298 PART 2TABLE 12 ( CONTINUED )


CABLE INSTALLATION

1 3 6

laid on the ground


No. ofTroughs

0.95 0.84 0.80

0.95

0.95

0.95

0.80

0.78

0.76

0.76

0.74

0.72

1

2

3

6

LAID ON CABLE RACKS

GROUP factor can be

considered = 1

No. of cable sideby side 2 9

0.90 0.84 0.80 0.75 0.73

0.75

0.71

0.70

0.68

0.73

0.69

0.68

0.66

No. ofRacks

0.95 0.84 0.80

0.95

0.95

0.95

0.80

0.78

0.76

0.76

0.74

0.72

1

2

3

6

0.75

0.71

0.70

0.68

0.73

0.69

0.68

0.66

1 3 6No. of CABLES 2 9

0.95 0.78 0.73 0.68 0.66No. of CABLES

> 20

cm

> 20

cm

> 20

cm

> 2cm d

> 2d



DIN 57 298 PART 2 VDE 0298 PART 2TABLE 13 CONTROL CABLE

Cable core size should be from 1.5 to 10 mm

1 2 3

No. of cores laid in

the ground

air

0.70

0.60

0.50

0.45

0.40

0.35

0.30

0.25

0.75

0.65

0.55

0.50

0.45

0.40

0.35

0.30

5

7

10

14

19

24

40

61

1) FACTORS TO BE USED WITH

TABLE 1 COLUMN 4 FOR INSTALLATION IN THE GROUND

TABLE 2 COLUMN 4 FOR INSTALLATION IN AIR.

2



TABLE 14 MAX. SHORT CIRCUT CURRENTFOR COPPER CABLE AT 1 SEC.

1 2 3 4 5 6 7 8 9 10 11 12

CONSTRUCTION COND.MAX.

TEMP . ATNORMALOPERA-

TION.

SHORTCIRCUITCONDU-

CTORMAX.

TEMP . 90 80 70 65 60 50 40 30 20

C C

Soft silverconnection 100 108 115 119 122 129 136 143 150160-

XLPE Cable 143 149 154 157 159 165 170 176 18125090

C C 85 80 70 65 60 50 40 30 20

PVC CABLE

< 300 mm

> 300 mm

104 108 115 119 122 129 136 143 15016085

Short circuit current A/mm

90 103 107 107 111 118 126 133 14014085

Isc for time (t) can be obtained from the following formula

Isc = ISC (1)

Where; Isc (1) = short circuit current at 1 sec.

t

Conductor temperature at the beginning of short circuit

2

2

2



TABLE 15 MAX. SHORT CIRCUT CURRENTFOR ALUMINIUM CABLE AT 1 SEC.

1 2 3 4 5 6 7 8 9 10 11 12

CONSTRUCTION COND.MAX.

TEMP . ATNORMALOPERA-

TION.

SHORTCIRCUITCONDU-

CTORMAX.

TEMP . 90 80 70 65 60 50 40 30 20

C C

XLPE Cable 94 98 102 104 105 109 113 116 12025090

C C 85 80 70 65 60 50 40 30 20

PVC CABLE

< 300 mm

> 300 mm

69 71 76 78 81 85 90 95 9916085

Short circuit current A/mm

60 62 68 71 73 78 83 88 9314085

Conductor temperature at the beginning of short circuit

2

2

2



LAYING INSTRUCTIONPERMISSIBLE BENDING RADII

Minimum bending radius as a multiple of completed cable diameter:

TYPE OF CABLE MULTIPLYING FACTOR

Single-core Multi-core

Non-metallic shielded 15 12 (VDE 0298)

Permissible pulls When laying power cables by machines, par-ticular attention must be paid to the permissibletensile forces. The formulae for obtaining theseare given in table underneath.

pulling head

on the

conductors

all types of cables F = A. (50 N / mm )(cable with Cu conductor)

F = A. (30 N / mm )(cable with Al conductor)

with pulling

stocking

all wire armoured cables

/e.g. NYFGY, NYFGYBY, etc)

Cu (AL) / PVC (XLPE) / SWA / PVC

F = K.D(K = 9 N / mm )

A = Total conductor cross-section in mm (without screen and concentric protective conductor)

D = Outside diameter od cable in mm.

If three single-core cable are laid simultaneously with a common pulling slocking, three cables are

used in the case of three laid up single-core cables as the basis for determining the permissible

pull and two cables in the case of uplaid up single-core cables.

pullingmethod

Constructionof cable

tensileforce

2

2

2

2

2



LOW VOLTAGE SINGLE CORE CABLE( IN TREFOIL FROMATION )

LINEAR RESISTANCE , REACTANCE AND VOLTAGE DROP OFPVC INSULATED ( 85 C ) COPPER CONDUCTOR

VD

1.5

Z85

XR (AC)85

R (DC)85

R (DC)20

SIZEMM

2.5

4.0

6.0

10

16

25

35

50

70

95

120

150

185

240

300

400

500

630

12.1

7.41

4.61

3.08

1.83

1.15

0.727

0.524

0.387

0.268

0.193

0.153

0.124

0.0991

0.0754

0.0601

0.0470

0.0366

0.0283

15.19

9.30

5.79

3.87

2.30

1.444

0.913

0.658

0.486

0.336

0.242

0.192

0.156

0.1244

0.0947

0.0754

0.0590

0.0459

0.0355

15.19

9.30

5.79

3.87

2.30

1.444

0.913

0.658

0.487

0.337

0.244

0.194

0.158

0.1272

0.0978

0.0800

0.0626

0.0504

0.0413

0.165

0.149

0.143

0.134

0.1132

0.124

0.121

0.115

0.111

0.105

0.103

0.100

0.100

0.099

0.097

0.096

0.094

0.092

0.091

15.19

9.30

5.79

3.87

2.30

1.449

0.921

0.668

0.499

0.353

0.265

0.218

0.187

0.161

0.138

0.124

0.113

0.105

0.100

21.22

13.04

8.17

5.50

3.32

2.13

1.39

1.031

0.790

0.576

0.445

0.373

0.323

0.279

0.236

0.210

0.184

0.165

0.152

R(DC) : DIRECT CURRENT RESISTANCE AT 20 C


R(AC) : ALTERNATING CURRENT RESISTANCE AT 85 C

X : REACTANCE,Ohm / KmZ : IMPEDANCE, Ohm / KmVD : VOLTAGE DROP,V / (Amp. km)

20

85

85

2



LOW VOLTAGE CABLE( MULTI CORE )

LINEAR RESISTANCE , REACTANCE AND VOLTAGE DROP OFPVC INSULATED ( 85 C ) COPPER CONDUCTOR

VD

1.5

Z85

XR (AC)85

R (DC)85

R (DC)20

SIZEMM

2.5

4.0

6.0

10

16

25

35

50

70

95

120

150

185

240

300

400

500

630

12.1

7.41

4.61

3.08

1.83

1.15

0.727

0.524

0.387

0.268

0.193

0.153

0.124

0.0991

0.0754

0.0601

0.0470

0.0366

0.0283

15.19

9.30

5.79

3.87

2.30

1.444

0.913

0.658

0.486

0.336

0.242

0.192

0.156

0.1244

0.0947

0.0754

0.0590

0.0459

0.0355

15.19

9.30

5.79

3.87

2.30

1.444

0.913

0.658

0.487

0.337

0.244

0.194

0.158

0.1272

0.0978

0.0800

0.0626

0.0504

0.0413

0.165

0.143

0.132

0.121

0.109

0.106

0.103

0.098

0.098

0.095

0.093

0.091

0.091

0.091

0.090

0.090

0.089

0.088

0.088

15.19

9.30

5.79

3.87

2.30

1.448

0.919

0.666

0.496

0.351

0.261

0.214

0.182

0.1564

0.1329

0.1204

0.1088

0.1014

0.0972

21.22

13.04

8.16

5.49

3.30

2.11

1.37

1.014

0.777

0.566

0.435

0.363

0.314

0.271

0.229

0.204

0.179

0.161

0.149





20

85

85

2



LOW VOLTAGE SINGLE CORE CABLE( IN TREFOIL FORMATION )

LINEAR RESISTANCE , REACTANCE AND VOLTAGE DROP OFXLPE INSULATED ( 90 C ) COPPER CONDUCTOR

VD

1.5

Z90

XR (AC)90

R (DC)90

R (DC)20

SIZEMM

2.5

4.0

6.0

10

16

25

35

50

70

95

120

150

185

240

300

400

500

630

12.1

7.41

4.61

3.08

1.83

1.15

0.727

0.524

0.387

0.268

0.193

0.153

0.124

0.0991

0.0754

0.0601

0.0470

0.0366

0.0283

15.43

9.45

5.88

3.93

2.333

1.486

0.927

0.668

0.493

0.342

0.246

0.195

0.158

0.126

0.0961

0.0766

0.0599

0.0467

0.0361

15.43

9.45

5.88

3.93

2.333

1.486

0.927

0.669

0.494

0.343

0.248

0.197

0.160

0.129

0.0993

0.0812

0.0636

0.0513

0.0420

0.165

0.149

0.143

0.134

0.132

0.124

0.121

0.115

0.111

0.105

0.103

0.100

0.100

0.099

0.097

0.096

0.094

0.094

0.091

15.43

9.45

5.88

3.93

2.337

1.471

0.935

0.679

0.506

0.359

0.269

0.221

0.189

0.163

0.139

0.126

0.114

0.105

0.100

21.43

13.25

8.30

5.58

3.37

2.16

1.41

1.046

0.800

0.584

0.451

0.377

0.326

0.282

0.238

0.212

0.186

0.167

0.153





20

90

90

2



LOW VOLTAGE CABLE( MULTI CORE )

LINEAR RESISTANCE , REACTANCE AND VOLTAGE DROP OFXLPE INSULATED ( 90 C ) COPPER CONDUCTOR

VD

1.5

Z90

XR (AC)90

R (DC)90

R (DC)20

SIZEMM

2.5

4.0

6.0

10

16

25

35

50

70

95

120

150

185

240

300

400

500

630

12.1

7.41

4.61

3.08

1.83

1.15

0.727

0.524

0.387

0.268

0.193

0.153

0.124

0.0991

0.0754

0.0601

0.0470

0.0366

0.0283

15.43

9.45

5.88

3.93

2.333

1.486

0.927

0.668

0.493

0.342

0.246

0.195

0.158

0.126

0.0961

0.0766

0.0599

0.0467

0.0361

15.43

9.45

5.88

3.93

2.333

1.486

0.927

0.669

0.494

0.343

0.248

0.197

0.160

0.129

0.0993

0.0812

0.0636

0.0513

0.0420

0.165

0.143

0.132

0.121

0.109

0.106

0.103

0.098

0.098

0.095

0.093

0.091

0.091

0.091

0.090

0.090

0.098

0.088

0.088

15.43

9.45

5.88

3.93

2.336

1.470

0.933

0.676

0.504

0.256

0.264

0.217

0.184

0.1579

0.1340

0.1212

0.1094

0.1019

0.0975

21.55

13.24

8.28

5.57

3.35

2.14

1.39

1.03

0.786

0.574

0.440

0.370

0.316

0.273

0.231

0.206

0.181

0.163

0.150





20

90

90

2



LOW VOLTAGE SINGLE CORE CABLE( IN TREFOIL FORMATION )

LINEAR RESISTANCE , REACTANCE AND VOLTAGE DROPXLPE INSULATED ( 90 C ) ALUMINIUM CONDUCTOR

VDZ90

XR (AC)90

R (DC)90

R (DC)20

SIZEMM

R(DC) : Direct Current Resistance at 20 C, Ohm/Km

R(DC) : Direct Current Resistance at 90 C, Ohm/Km

R(AC) : Alternating Current Resistance at 90 C, Ohm/Km

20

90

90

2

16 1.91 2.449 2.449 0.124 2.452 3.522

25 1.20 1.539 1.539 0.121 1.544 2.258

35 0.868 1.113 1.113 0.115 1.119 1.662

50 0.641 0.822 0.822 0.111 0.829 1.254

70 0.443 0.568 0.568 0.105 0.578 0.896

95 0.320 0.410 0.411 0.103 0.424 0.677

120 0.253 0.324 0.325 0.100 0.340 0.554

150 0.206 0.264 0.265 0.100 0.283 0.471

185 0.164 0.210 0.211 0.099 0.233 0.395

240 0.125 0.160 0.162 0.097 0.189 0.325

300 0.100 0.128 0.130 0.096 0.162 0.280

400 0.0778 0.100 0.102 0.094 0.139 0.239

500 0.0605 0.078 0.081 0.092 0.123 0.208

630 0.0469 0.060 0.064 0.091 0.111 0.183

LOW VOLTAGE MULTI CORE CABLELINEAR RESISTANCE , REACTANCE AND VOLTAGE DROP

XLPE INSULATED ( 90 C ) ALUMINIUM CONDUCTOR

VDZ90

XR (AC)90

R (DC)90

R (DC)20

SIZEMM2

16 1.91 2.449 2.449 0.106 2.451 3.504

25 1.20 1.539 1.539 0.103 1.542 2.240

35 0.868 1.113 1.113 0.098 1.117 1.664

50 0.641 0.822 0.822 0.098 0.828 1.241

70 0.443 0.568 0.568 0.095 0.576 0.886

95 0.320 0.410 0.411 0.093 0.421 0.666

120 0.253 0.324 0.325 0.091 0.337 0.545

150 0.206 0.264 0.265 0.091 0.280 0.462

185 0.164 0.210 0.211 0.091 0.230 0.387

240 0.125 0.160 0.162 0.090 0.185 0.318

300 0.100 0.128 0.130 0.090 0.158 0.74

400 0.0778 0.100 0.102 0.089 0.135 0.234

500 0.0605 0.078 0.081 0.088 0.120 0.204

630 0.0469 0.060 0.064 0.088 0.109 0.180

X : Reactance,Ohm / Km

Z : Impedance, Ohm / Km

VD : Voltage Drop (Phase to Phase), V/(A.km)



Guidelines for the selection of the required size of cable

The required sizes of cable shall be selected based on the following steps :

Ampacity : Based on the required ampacity and the installation condition, a suitable sizeof cable shall be selected.

Voltage drop : The suitability of the above selected size shall be cross checked with the voltage drop. If it is within the limit the selection is O.K. Otherwise the higher size (whosevoltage drop suits the requirement) shall be selected.

Following is an example for the above :

Example :150 meters of three core cable, XLPE insulated, PVC sheathed, copper cable installedunderground to carry 100 amperes load, supply voltage 380 V, three phase system 60Hz, Ground temperature 40 C, soil thermal resistivity 2.5 k m/w and load factor 1.

For 35 mm cable, From table 1 of this catalogue the ampacity is 173 Amp.Derating factors:Soil thermal resistivity and ground temperature (Table 3) = 0.68Group and load factor (Table 8) =0.89Therefore, the derated current is 173 x 0.68x0.89 = 104 Amps, which satisfies therequirement.

Verification of Voltage Drop :

Voltage drop Vap = V / A / kmwhere

V = Maximum permissible voltage drop (say 2.5%)V = System voltage (here 380 Volts)L = Length in meters (here 150 m)I = Current (104 Amp)

Therefore, V = V / A / km

= 0.609 V / A / km

From table on page # 23 of this catalogue, the voltage drop of 35 mm XLPE insulated multicore copper cable is 1.03 V/A/Km, which is much higher than the requirement of 0.609 V/A/Km. The voltage drop of 70 mm cable is 0.574 V/A/Km which iswithin the limit. Therefore, the suitable size is 70 mm .

2.5 x 1000 x 380104 x 150 x 100

V x 1000 x VI x L x 100

P

ap

2

2

2

P

2


Guidelines for the selection of the required size of cable

riyadh cables group of companies (rcgc), is a premier

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