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CTY TNHH Daây & Caùp Ñieän Vieät Nam (CADIVI)
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COÂNG TY COÅ PHAÀN DAÂY CAÙP ÑIEÄN VIEÄT NAM (CADIVI)

HÖÔÙNG DAÃN LÖÏA CHOÏN
VAØ SÖÛ DUÏNG CAÙP HAÏ THEÁ
CAÙCH ÑIEÄN
PVC HOAËC XLPE
INSTRUCTION OF CHOOSING AND USING OF
LOW VOLTAGE CABLES, PVC OR XLPE INSULATED

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HÖÔÙNG DAÃN LÖÏA CHOÏN VAØ SÖÛ DUÏNG CAÙP HAÏ THEÁ
CAÙCH ÑIEÄN PVC HOAËC XLPE
INSTRUCTION OF CHOOSING AND USING OF
LOW VOLTAGE CABLES, PVC OR XLPE INSULATED
________________________________________________________________________________________
A/ CHOÏN TIEÁT DIEÄN RUOÄT DAÃN:
Khi choïn caùp, khaùch haøng caàn xem xeùt nhöõng yeáu
toá sau:
- Doøng ñieän ñònh möùc
- Ñoä suït aùp
- Doøng ñieän ngaén maïch
- Caùch laép ñaët
- Nhieät ñoä moâi tröôøng hoaëc nhieät ñoä ñaát
I/ CAÙP ÑIEÄN LÖÏC
I.1/ CAÙP CAÙCH ÑIEÄN PVC
I.1.1/ Doøng ñieän ñònh möùc:
Doøng ñieän chaïy trong ruoät caùp thì seõ sinh nhieät laøm
cho caùp noùng leân. Khi nhieät ñoä caùp vöôït quaù möùc
cho pheùp thì phaûi choïn caùp coù tieát dieän ruoät daãn lôùn
hôn.
Caùc baûng veà doøng ñieän ñònh möùc sau ñaây döïa treân :
- Nhieät ñoä laøm vieäc cho pheùp toái ña cuûa ruoät daãn.
- Nhieät ñoä khoâng khí
- Nhieät ñoä ñaát
- Nhieät trôû suaát cuûa ñaát.
- Ñoä saâu laép ñaët (khi choân caùp trong ñaát)
- Ñieàu kieän laép ñaët
I.1.1.1/ Caùp treân khoâng
Caùp laép treân khoâng ña soá laø trong caùc toøa nhaø neân
doøng ñieän ñònh möùc ñöôïc tính vôùi nhieät ñoä khoâng
khí laø 300
C, caùp khoâng bò naéng roïi tröïc tieáp vaø
khoâng khí löu thoâng töï do.
Khi caùp bò naéng roïi tröïc tieáp, doøng ñieän ñònh möùc
seõ giaûm ñi.
Doøng ñieän ñònh möùc trong caùc baûng 1,2,3,4 cho caùp
laép ñaët trong caùc ñieàu kieän nhö sau :
a) Caùp moät loõi :
 2 hoaëc 3 sôïi caùp moät loõi laép theo moät maët ñöùng,
treân töôøng hay trong möông caùp hôû. khoaûng caùch töø
töôøng ñeán beà maët caùp phaûi lôùn hôn hoaëc baèng
20mm, khoaûng caùch taâm 2 sôïi caùp keà nhau baèng 2
laàn ñöôøng kính cuûa caùp.
Vôùi 2 caùp 1 loõi, doøng ñieän ñònh möùc ñöôïc aùp duïng
an toaøn cho tröôøng hôïp 2 sôïi caùp laép ñaët treân caùc
thanh ngang coá ñònh treân töôøng, khoaûng caùch giöõa
taâm 2 sôïi caùp nhö treân, hoaëc caùp tieáp xuùc nhau suoát
chieàu daøi caùp.
 Vôùi 3 caùp 1 loõi laép ñaët theo hình 3 laù, theo maët
ñöùng coá ñònh treân töôøng hay trong maùng caùp hôû,
khoaûng caùch tính töø töôøng ñeán beà maët caùp phaûi lôùn
hôn hoaëc baèng 20mm.
b) Caùp nhieàu loõi :
Khoâng nhö caùp moät loõi, caùp nhieàu loõi ñöôïc laép ñaët
ñôn leû theo moät maët ñöùng coá ñònh treân töôøng hay
A/ SELECTION OF CROSS-SECTIONNAL
AREA OF CONDUCTOR:
In order to choose the right power cable, one has to consider:
- The current rating
- The voltage drop
- The short circuit rating
- The installation methods
- The ambient temperature or ground temperature
I/ POWER CABLE
I.1/ PVC INSULATED POWER CABLE
I.1.1/ Current rating
When electric current flows through the conductor of a cable the
electrical resistance of the conductor generates heat. When a
temperature greater than that allowed is reached by the cable due to
heat generation, a larger conductor size (with lower electrical
resistance ) has to be selected.
The current rating depends on the following factors:.
- Maximum operating temperature of conductor
- Ambient air temperature
- Ground temperature
- Soil thermal resistivity
- Depth of laying ( for cable laid direct in the ground)
- Conditions of the installation
I.1.1.1/ Cables installed in air:
It is anticipated that many of the “in air” installation will be in
buildings, and the ratings are therefore given on the basis of an
ambient air temperature of 300
C
It should be noted that all ratings for cables run in free air have
been based on the assumption that they are shielded from the direct
rays of the sun without restriction of ventilation. The ratings for
cables subjected to solar radiation should be reduced to take
account of this factor
The ratings given in Tables 1,2,3,4 are for cables installed under
defined conditions
a) Single core cables
 Two or three single core cables are installed one above the other,
fixed to the vertical surface of a wall or open cable trench as
follows, the distance being at least 20 mm in each instance.
Cables are installed at a distance between centres of twice the
overall diameter of the cable.
The ratings for two cables may be applied with safety in instances
where such cables are installed in horizontal formation on brackets
fixed to a wall, either spaced as indicated above, or touching
throughout.
 Three single core cables are installed in trefoil formation, fixed
to the vertical surface of a wall or open cable trench, the cables
touching throughout and the distance between the wall and the
surface of the nearest cable being at least 20 mm.
The cables are assumed to be remote from iron, steel, or ferro-
concrete, other than the cable supports.
(b) Multicore cables
Cables of all types other than single core cables are installed singly,
fixed to the vertical surface of a wall or open cable trench, the

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trong möông caùp hôû, khoaûng caùch töø töôøng ñeán beà
maët caùp phaûi lôùn hôn hoaëc baèng 20mm.
Neáu nhaát thieát phaûi laép ñaët caùp vôùi khoaûng caùch
nhoû hôn qui ñònh thì soá lieäu seõ cho rieâng trong caùc
baûng coù tieâu ñeà "Clipped direct to a surface. ."
theo IEE
distance between the surface of the cable and the wall being at least
20 mm in every instance.
If it is necessary for cables to be installed at distances less than
those described above, then the values tabulated under the heading."
"Clipped direct to a surface. . in the IEE Wiring Regulations should
be employed.
Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa caùp ruoät nhoâm , caùch ñieän PVC, voû PVC coù giaùp baûo veä, laép treân khoâng
Current ratings and Voltage drop for Alluminium conductors, PVC insulated, armoured, PVC oversheathed cables,
Installed in air
Baûng 1 ( Table 1)
Tieát dieän
ruoät daãn
Nominal
area of
conductor
1 loõi (Single core ) 2 loõi
Two core
3 vaø 4 loõi
Three and four core2 caùp ñaët caùch khoaûng
Two cables spaced
3 caùp tieáp xuùc nhau theo
hình 3 laù
Three cables trefoil touching
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
mm2
A mV A mV A mV A mV
16 80 4.7 65 4.0 72 4,6 61 4,0
25 109 3.1 85 2.5 92 2,9 80 2,5
35 131 2.2 110 1.8 113 2,1 98 1,8
50 159 1,6 133 1,3 136 1,5 120 1,8
70 200 1,1 166 0,94 173 1,1 151 0,93
95 245 0,82 205 0,69 213 0,79 188 0,68
120 280 0,68 239 0,56 - - 218 0,54
150 325 0,57 272 0,46 - - 248 0,45
185 371 0,49 317 0,38 - - 288 0,37
240 437 0,41 375 0,31 - - 344 0,29
300 498 0,37 431 0,27 - - 396 0,25
380 559 0,34 497 0,24 - - - -
480 629 0,31 569 0,21 - - - -
600 697 0,29 637 0,19 - - - -
740 770 0,28 719 0,18 - - - -
960 832 0,27 803 0,17 - - - -
1200 902 0,27 884 0,16 - - - -
Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa caùp ruoät nhoâm , caùch ñieän PVC, voû PVC khoâng giaùp baûo veä, laép treân khoâng
Current ratings and Voltage drop for Alluminium conductors, PVC insulated, unarmoured, PVC oversheathed cables
Installed in air
Baûng 2 ( Table 2)
Tieát dieän
ruoät daãn
Nominal
area of
conductor
1 loõi (Single core) 2 loõi
Two core
3 vaø 4 loõi
Two cables spaced
3 caùp (Three cables)
Tieáp xuùc nhau theo hình 3 laù
Trefoil touching
Treân cuøng maët phaúng vaø
caùch khoaûng
Laid flat spaced
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
mm2
A mV A mV A mV A MV
16 78 4,7 64 4,0 76 4,0 70 4,6 59 4,0
25 105 3,1 83 2,5 101 2,5 90 2,9 78 2,5
35 128 2,2 105 1,8 123 1,8 110 2,1 96 1,8
50 153 1,6 129 1,3 149 1,3 134 1,5 117 1,3
70 194 1,1 164 0,94 189 0,95 169 1,1 149 0,93
95 241 0,81 202 0,68 234 0,70 209 0,79 183 0,68
120 281 0,66 236 0,55 273 0,58 - - 212 0,54
150 324 0,56 271 0,46 313 0,49 - - 243 0,45
185 373 0,47 315 0,37 364 0,42 - - 281 0,37
240 446 0,40 376 0,30 434 0,40 - - 336 0,29
300 515 0,35 436 0,26 503 0,36 - - 387 0,25
380 601 0,32 509 0,22 588 0,33 - - - -
480 697 0,29 591 0,20 682 0,30 - - - -
600 798 0,28 674 0,18 781 0,28 - - - -
740 923 0,27 776 0,17 903 0,26 - - - -
960 1091 0,26 810 0,15 1068 0,24 - - - -
1200 1247 0,25 1028 0,15 1221 0,23 - - - -

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Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa caùp ruoät ñoàng, caùch ñieän PVC, voû PVC coù giaùp baûo veä, laép treân khoâng
Current ratings and Voltage drop for Copper conductors, PVC insulated, armoured, PVC oversheathed cables
Installed in air
Baûng 3 ( Table 3)
Tieát dieän
ruoät daãn
Nominal
area of
conductor
Two core
3 vaø 4 loõi
Two cables spaced
hình 3 laù
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
mm2
A mV A mV A mV A mV
1,5 26 33 24 26 23 29 20 25
2,5 33 21 29 16 31 17 26 15
4 50 12 39 9,7 41 11 36 9,5
6 62 8,0 44 6,5 53 7,4 45 6,4
10 80 4,8 64 3,8 72 4,4 62 3,8
16 108 3,2 88 2,3 96 2,8 82 2,4
25 140 1,9 121 1,5 128 1,7 109 1,5
35 170 1,4 150 1,1 156 1,3 133 1,1
50 217 0,98 181 0,82 189 0,94 162 0,82
70 271 0,71 228 0,58 237 0,66 205 0,57
95 332 0,54 280 0,44 293 0,49 252 0,42
120 383 0,46 326 0,36 338 0,40 291 0,35
150 431 0,41 371 0,31 384 0,34 334 0,29
185 489 0,37 425 0,27 445 0,29 383 0,25
240 568 0,33 500 0,23 525 0,24 451 0,21
300 640 0,31 571 0,20 598 0,21 514 0,18
400 707 0,29 649 0,19 685 0,19 589 0,17
500 777 0,28 729 0,18 - - - -
630 856 0,27 817 0,16 - - - -
800 905 0,26 881 0,16 - - -
1000 967 0,26 949 0,15 - - - -
Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa caùp ruoät ñoàng , caùch ñieän PVC, voû PVC khoâng giaùp baûo veä, laép treân khoâng
Current ratings and Voltage drop for Copper conductors, PVC insulated, unarmoured, PVC oversheathed cables
Installed in air
Baûng 4 ( Table 4)
Tieát dieän
ruoät daãn
Nominal
area of
conductor
Two core
3 vaø 4 loõi
Two cables spaced
3 caùp (Three cables)
Tieáp xuùc nhau theo hình laù
Trefoil touching
Treân cuøng moät maët phaúng
vaø caùch khoaûng
Laid flat spaced
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
mm2
A mV A mV A mV A mV A mV
1,5 24 30 21 26 23 26 22 27 19 24
2,5 31 19 27 14 30 15 29 16 24 13
4 45 10 36 9,5 43 9,5 38 10 32 9
6 58 6 40 7,5 50 6,8 45 7 38 6
10 76 4,1 58 3,8 70 3,8 68 4 55 3,3
16 101 3,0 85 2,4 95 2,5 91 2,8 79 2,4
25 135 1,8 118 1,5 128 1,7 122 1,7 103 1,5
35 169 1,4 145 1,1 160 1,2 149 1,3 128 1,1
50 207 0,97 173 0,82 201 0,83 182 0,94 156 0,82
70 262 0,70 219 0,58 255 0,60 229 0,66 197 0,57
95 325 0,53 273 0,43 317 0,47 284 0,49 243 0,42
120 379 0,45 318 0,35 368 0,40 330 0,40 284 0,35
150 435 0,39 365 0,30 424 0,35 379 0,34 324 0,29
185 504 0,35 423 0,25 492 0,33 436 0,29 374 0,25
240 602 0,31 505 0,22 588 0,32 519 0,24 446 0,21
300 697 0,29 583 0,19 681 0,31 598 0,21 572 0,18
400 815 0,28 679 0,18 796 0,28 695 0,19 593 0,17
500 948 0,26 782 0,16 927 0,27 - - - -
630 1108 0,25 900 0,15 1083 0,25 - - - -
800 1277 0,25 1080 0,15 1249 0,23 - - - -
1000 1437 0,24 1134 0,14 1412 0,22 - - - -

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Thoâng soá laép ñaët :
Nhieät ñoä khoâng khí 300
C
Nhieät ñoä ruoät daãn toái ña khi caùp taûi doøng ñieän ñònh
möùc 700
C
Chæ neân cho caùp lieân tuïc mang ñuû doøng ñieän ñònh möùc
khi doøng ñieän toái thieåu cuûa maïch baûo veä khoâng vöôït
quaù 1,45 laàn doøng ñieän ñònh möùc.
Vieäc laép ñaët nhieàu sôïi caùp seõ khoâng laøm giaûm doøng
ñieän ñònh möùc neáu:
- Khoaûng caùch ngang giöõa caùc maïch ñieän khoâng
nhoû hôn 2 laàn ñöôøng kính moät sôïi caùp
- Khoaûng caùch doïc giöõa caùc maïch ñieän khoâng nhoû
hôn 4 laàn ñöôøng kính moät sôïi caùp
- Neáu coù hôn 3 maïch ñieän thì laép chuùng naèm ngang.
Basic assumptions and conditions of installation
Ambient air temperature 300
C
Maximum conductor operating temperature at rated current 700
C
Cables shall only be continuously operated at their full rating if the
minimun current at which circuit protection is designed to operate
does not exceed 1,45 times the values tabulated.
Effect of grouping of cables: no reduction in rating is necessary
providing that:
- The horizontal clearance between circuits is not less than twice
the overall diameter of an individual cable.
- The vertical clearance between circuits is not less than 4 times
the diameter of an individual cable
- If the number of circuits exceeds 3, they are installed in a
horizontal plane
Heä soá hieäu chænh doøng ñònh möùc khi nhieät ñoä khoâng khí thay ñoåi
Rating factors for other ambient air temperatures
Baûng 5 (Table 5)
Nhieät ñoä moâi tröôøng
Ambient air temperature
25 35 40 45 50 55
Heä soá hieäu chænh
Rating factor
1,06 0,94 0,87 0,79 0,70 0,61
I.1.1.2/ Caùp choân tröïc tieáp trong ñaát I.1.1.2/ Cables laid direct in ground
Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa caùp ruoät nhoâm, caùch ñieän PVC, voû PVC, coù giaùp baûo veä, choân trong ñaát
Current ratings and Voltage drop for Alluminium conductors, PVC insulated, armoured, PVC oversheathed cables
Laid direct in ground
Baûng 6 ( Table 6)
Tieát dieän
ruoät daãn
Nominal
area of
conductor
Two core
3 vaø 4 loõi
Two cables spaced
hình 3 laù
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
mm2
A mV A mV A mV A mV
16 98 4,7 76 4,0 91 4,6 77 4,0
25 122 3,1 102 2,5 118 2,9 100 2,5
35 148 2,2 125 1,8 142 2,1 120 1,8
50 180 1,6 154 1,3 168 1,5 143 1,3
70 221 1,1 188 0,92 209 1,1 176 0,93
95 265 0,80 226 0,68 250 0,79 213 0,68
120 302 0,64 257 0,55 - - 243 0,54
150 338 0,54 288 0,46 - - 272 0,45
185 382 0,44 326 0,38 - - 309 0,37
240 442 0,36 377 0,31 - 360 0,29
300 498 0,31 424 0,26 - - 407 0,25
380 558 0,27 475 0,23 - - - -
480 626 0,24 532 0,21 - - - -
600 691 0,22 586 0,19 - - - -
740 764 0,21 648 0,18 - - - -
960 829 0,19 701 0,17 - - - -
1200 895 0,18 755 0,16 - - - -

6
Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa caùp ruoät ñoàng , caùch ñieän PVC, voû PVC coù giaùp baûo veä, choân trong ñaát
Current ratings and Voltage drop for Copper conductors, PVC insulated, armoured, PVC oversheathed cables,
Baûng 7 ( Table 7)
Tieát dieän
ruoät daãn
Nominal
area of
conductor
Two core
3 vaø 4 loõi
Two cables spaced
hình 3 laù
Trefoil touching
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
mm2
A mV A mV A mV A mV
1,5 33 32 29 25 32 29 27 25
2,5 44 20 38 15 41 17 35 15
4 59 11 53 9,5 55 11 47 9,5
6 75 9 66 6,4 69 7,4 59 6,4
10 101 4,8 86 3,8 92 4,4 78 3,8
16 128 3,2 110 2,4 119 2,8 101 2,4
25 168 1,9 142 1,5 158 1,7 132 1,5
35 201 1,4 170 1,1 190 1,3 159 1,1
50 238 0,97 203 0,82 225 0,94 188 0,82
70 292 0,67 248 0,58 277 0,66 233 0,57
95 349 0,50 297 0,44 332 0,49 279 0,42
120 396 0,42 337 0,36 377 0,40 317 0,35
150 443 0,36 376 0,31 422 0,34 355 0,29
185 497 0,31 423 0,27 478 0,29 401 0,25
240 571 0,26 485 0,23 561 0,24 462 0,21
300 640 0,23 542 0,20 616 0,21 517 0,18
400 708 0,22 600 0,19 693 0,19 580 0,17
500 780 0,20 660 0,18 - - - -
630 856 0,19 721 0,16 - - - -
800 895 0,18 756 0,16 - - - -
1000 939 0,18 797 0,15 - - - -
Nhieät trôû suaát cuûa ñaát : 1,2 0
Cm/W
Nhieät ñoä ñaát : 150
C
Ñoä saâu choân caùp : 0,5m (tính ñeán taâm
cuûa caùp hoaëc taâm cuûa nhoùm caùp hình 3 laù)
Nhieät ñoä laøm vieäc toái ña cuûa ruoät daãn laø 700
C
Chæ neân cho caùp lieân tuïc mang ñuû doøng ñieän ñònh
möùc khi doøng ñieän toái thieåu cuûa maïch baûo veä khoâng
vöôït quaù 1,3 laàn doøng ñieän ñònh möùc.
Doøng ñieän ñònh möùc cuûa caùp choân tröïc tieáp trong ñaát
phuï thuoäc vaøo nhieät ñoä ñaát vaø nhieät trôû suaát cuûa ñaát.
Heä soá hieäu chænh trong baûng 8 duøng ñeå hieäu chænh
doøng ñieän ñònh möùc theo söï thay ñoåi cuûa nhieät ñoä
ñaát.
Khi nhöõng ñieàu kieän hoaït ñoäng cuûa caùp ñöôïc xaùc
ñònh moät caùch chính xaùc, vaø coù hieåu bieát veà ñaát suoát
caû loä trình ñi caùp, khaùch haøng coù theå xaùc ñònh doøng
ñieän ñònh möùc moät caùch chính xaùc hôn qua söû duïng
heä soá nhieät trôû suaát cuûa ñaát, heä soá gheùp nhoùm, heä soá
ñieàu chænh theo ñoä saâu ñaët caùp… trong caùc baûng
8,9,10,11,12.
Ground thermal resistivity 1.2 0
C m/W
Ground temperature 15 0
C
Depth of laying 0,5 metre (to the centre of cable or trefoil group
of cables)
Maximum operating conductor temperature at rated current: 700
C.
minimum current at which circuit protection is designed to operate
does not exceed 1,3 times the values tabulated.
Rating factors
Ratings for cables installed direct in the ground are based on
values of soil temperature and soil thermal resistivity
Rating factors to take account of variation in ground temperature
are given with the current rating tables. Where conditions of
operation can be fairly accurately estimated, and knowledge of the
soil along the route is available, it is possible to determine the
ratings more precisely by the use of the soil thermal resistivity
factors, grouping factors and factors for the depths of laying given
in Tables 8 to 12.
Heä soá hieäu chænh doøng ñònh möùc khi nhieät ñoä ñaát thay ñoåi
Rating factors for other ground temperatures
Baûng 8 (Table 8)
Nhieät ñoä ñaát
Ground temperature (0
C)
20 25 30 35 40 45
Rating factor
0,95 0,90 0,85 0,80 0,74 0,67

7
Heä soá hieäu chænh doøng ñònh möùc khi giaù trò nhieät trôû suaát cuûa ñaát thay ñoåi
Rating factors for variation in thermal resistivity of soil
Baûng 9 (Table9)
Loaïi vaø côõ caùp
Type & Size of cable (mm2
)
Nhieät trôû suaát cuûa ñaát
Soil thermal resistivity in 0
Cm/W
0,8 0,9 1,0 1,5 2,0 2,5
Caùp moät ruoät (Single core cables)
Döôùi 150 (Up to 150)
Töø 185 ñeán 300 (From 185 to 300)
Töø 380 ñeán 1200 (From 380 to 1200)
1,16
1,17
1,17
1,12
1,12
1,12
1,07
1,07
1,07
0,91
0,91
0,91
0,81
0,80
0,80
0,73
0,73
0,73
Caùp nhieàu ruoät (Multicore cables)
Töø 25 ñeán 150 (From 25 to 150)
Töø 185 ñeán 400 (From 185 to 400)
1,12
1,14
1,16
1,08
1,10
1,10
1,05
1,06
1,07
0,93
0,92
0,92
0,84
0,82
0,81
0,77
0,75
0,74
Heä soá hieäu chænh doøng ñònh möùc khi ñoä saâu choân caùp thay ñoåi
Rating factors for depth of laying ( to centre of cable or trefoil group of cables)
Baûng 10 (Table 10)
Ñoä saâu ñaët caùp
Depth of laying
(m)
600/1000 V
Döôùi 50 mm2
(Up to 50mm2
)
70 ñeán 300 mm2
(70 to 300 mm2
)
Treân 300 mm2
(Above 300 mm2
)
0,50 1,00 1,00 1,00
0,60 0,99 0,98 0,97
0,80 0,97 0,96 0,94
1,00 0,95 0,93 0,92
1,25 0,94 0,92 0,89
1,50 0,93 0,90 0,87
1,75 0,92 0,89 0,86
2,00 0,91 0,88 0,85
2,50 0,90 0,87 0,84
3,00 hoaëc hôn
(3,00 or more)
0,89 0,86 0,82
Ñoä saâu choân caùp tính ñeán taâm cuûa caùp hay taâm cuûa nhoùm caùp hình 3 laù
Depth of laying : to centre of cable or trefoil group of cables
Heä soá hieäu chænh doøng ñònh möùc khi gheùp nhoùm caùp 1 loõi , ñaët theo hình ba laù hay treân maët phaúng ngang
Group rating factors for circuits of three single core cables, in trefoil or laid in flat touching, horizontal formation
Soá maïch
(Number
of circuits)
Khoaûng caùch ( Spacing) (m)
Tieáp xuùc tröïc tieáp (Touching) 0,15 0,3 0,45 0,6
Xeáp theo hình
ba laù (Trefoil )
Xeáp treân maët phaúng
(Laid flat )
2 0,78 0,81 0,83 0,88 0,91 0,93
3 0,66 0,70 0,73 0,79 0,84 0,87
4 0,61 0,64 0,68 0,73 0,81 0,85
5 0,56 0,60 0,64 0,73 0,79 0,85
6 0,53 0,57 0,61 0,71 0,78 0,82
spacing Spacing*

8
Heä soá hieäu chænh doøng ñònh möùc cuûa caùp nhieàu loõi ñaët treân maët phaúng ngang
Group rating factors for Multicore cables in horizontal formation
Soá caùp trong moät
nhoùm
(Number of cables in
group )
Tieáp xuùc tröïc tieáp
(Touching)
0,15 0,3 0,45 0,6
2 0,81 0,87 0,91 0,91 0,95
3 0,70 0,78 0,84 0,84 0,90
4 0,63 0,74 0,81 0,81 0,89
5 0,59 0,70 0,78 0,78 0,87
6 0,55 0,68 0,77 0,77 0,87
I.1.1.3/ Caùp ñi trong oáng ñôn tuyeán choân trong ñaát I.1.1.3/ Cable run in single way ducts
Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa caùp ruoät nhoâm, caùch ñieän PVC, voû PVC, coù giaùp baûo veä, ñi trong oáng ñôn
tuyeán choân trong ñaát
(Current ratings and Voltage drop for Alluminium conductors, PVC insulated, armoured, PVC oversheathed cables,
Run in single way ducts)
Baûng 13 ( Table 13 )
Tieát dieän
ruoät daãn
Nominal
area of
conductor
Two core
3 vaø 4 loõi
Three and four core2 caùp : oáng tieáp xuùc nhau
Two cables : ducts touching
3 caùp: oáng xeáp theo hình ba laù tieáp
xuùc nhau
Three cables: ducts trefoil touching
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
mm2
A mV A MV A mV A mV
16 87 4,7 78 4,2 75 4,6 62 4,0
25 115 3,1 100 2,6 96 2,9 81 2,5
35 140 2,2 123 1,9 115 2,1 97 1,8
50 166 1,6 154 1,4 137 1,5 116 1,3
70 204 1,2 188 1,0 170 1,1 144 0,93
95 241 0,88 222 0,76 204 0,79 174 0,68
120 274 0,74 252 0,64 - - 199 0,54
150 306 0,64 280 0,55 - - 223 0,45
185 335 0,55 306 0,48 - - 254 0,37
240 381 0,48 347 0,41 - - 298 0,29
300 423 0,43 384 0,37 - - 338 0,25
380 455 0,39 411 0,34 - - - -
480 498 0,36 449 0,31 - - - -
600 538 0,34 483 0,29 - - - -
740 584 0,32 523 0,27 - - - -
960 619 0,29 550 0,25 - - - -
1200 664 0,28 558 0,24 - - - -
spacing

9
Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa caùp ruoät ñoàng , caùch ñieän PVC, voû PVC, coù giaùp baûo veä, ñi trong oáng ñôn
tuyeán choân trong ñaát
Current ratings and Voltage drop for Copper conductors, PVC insulated, armoured, PVC oversheathed cables,
Run in single way ducts
Baûng 14 ( Table 14 )
Tieát dieän
ruoät daãn
Nominal
area of
conductor
Two core
3 vaø 4 loõi
Three and four core2 caùp : oáng tieáp xuùc nhau
Two cables : ducts touching
3 caùp: oáng xeáp theo hình ba laù tieáp
xuùc nhau
Three cables: ducts trefoil touching
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
mm2
A mV A mV A mV A mV
1,5 30 34 28 27 26 29 22 25
2,5 41 22 35 16 34 17 29 15
4 59 12 48 10.5 45 11 38 9,5
6 69 10 60 7.0 57 7,4 48 6,4
10 90 5.0 84 4.0 76 4,4 64 3,8
16 114 3.4 107 2.6 98 2,8 83 2,4
25 150 2.0 139 1.6 129 1,7 107 1,5
35 175 1.4 168 1.2 154 1,3 129 1,1
50 216 1,0 199 0,88 183 0,94 153 0,82
70 262 0,76 241 0,66 225 0,66 190 0,57
95 308 0,61 282 0,53 271 0,49 228 0,42
120 341 0,54 311 0,47 309 0,40 260 0,35
150 375 0,48 342 0,42 346 0,34 292 0,29
185 414 0,44 375 0,38 393 0,29 331 0,25
240 463 0,40 419 0,34 455 0,24 382 0,21
300 509 0,37 459 0,32 510 0,21 428 0,18
400 545 0,34 489 0,30 574 0,19 490 0,17
500 585 0,32 523 0,28 - - - -
630 632 0,30 563 0,26 - - - -
800 662 0,28 587 0,25 - - - -
1000 703 0,27 621 0,23 - - - -
Nhieät trôû suaát cuûa ñaát: 1,20
Cm/W
C
Ñoä saâu choân caùp : 0,5m (tính ñeán taâm cuûa oáng ñôn
chöùa caùp hoaëc taâm cuûa moät nhoùm oáng hình ba laù
chöùa caùp)
C
Chæ neân cho caùp lieân tuïc mang ñuû doøng ñieän ñònh möùc
khi doøng ñieän toái thieåu cuûa maïch baûo veä khoâng vöôït
quaù 1,45 laàn doøng ñieän ñònh möùc.
Caùch laép ñaët :
Thuaät ngöõ “oáng” ñeå chæ caùc loaïi oáng baèng ñaát nung,
baèng sôïi hoaëc baèng theùp. Khoâng söû duïng oáng theùp
cho caùp moät loõi trong löôùi ñieän xoay chieàu. Moãi oáng
chæ chöùa moät sôïi caùp
Ground thermal resistivity 1.2 0
C m/W
C
Depth of laying 0. 5 metre (to the centre of duct or
trefoil group of ducts group of cables)
Maximum operating conductor temperature at rated current 700
C
minimum current at which circuit protection is designed to operate
does not exceed 1,45 times the values tabulated
Method of installation:
The 'term" applies to a single earthenware, fibre or ferrous pipe
except that in the case of single core cables for use in ac systems,
ferrous ducts should not be employed. Rating are given for ducts
containning one cable each.
Kích thöôùc oáng theo ñöôøng kính caùp ( Size of duct are based on values of Cable overall diameter)
Ñöôøng kính toång cuûa caùp
Cable overall diameter (mm)
Kích thöôùc oáng (Size of duct)
Ñöôøng kính trong
Inside diameter (mm)
Ñöôøng kính ngoaøi
Outside diameter (mm)
Nhoû hôn hoaëc baèng 65
Up to and including 65
100 130
Töø 65 ñeán 90
Above 65 up to and including 90
125 160

10
Heä soá hieäu chænh doøng ñònh möùc khi nhieät ñoä ñaát thay ñoåi.
Rating factors for other ground temperatures
Baûng 16 (Table 16 )
C)
20 25 30 35 40 45
Rating factor
0,95 0,90 0,85 0,80 0,74 0,67
Heä soá hieäu chænh doøng ñònh möùc khi giaù trò nhieät trôû suaát cuûa ñaát thay ñoåi.
Rating factors for variation in thermal resistivity of soil
Baûng 17 (Table17)
Loaïi vaø côõ caùp
Type &Size of cable (mm2
)
Nhieät trôû suaát cuûa ñaát
Soil thermal resistivity in 0
Cm/W
0,8 0,9 1,0 1,5 2,0 2,5
Caùp moät ruoät (Single core cables)
Töø 185 ñeán 300 (From 185 to 300)
Töø 300 ñeán 1200 (From 300 to 1200)
1,10
1,11
1,12
1,07
1,08
1,08
1,04
1,05
1,05
0,94
0,93
0,93
0,86
0,85
0,84
0,80
0,79
0,78
Caùp nhieàu ruoät (Multicore cables)
Töø 25 ñeán 185 (From 25 to 185)
Töø 185 ñeán 400 (From 185 to 400)
1,04
1,06
1,07
1,03
1,04
1,05
1,02
1,03
1,03
0,97
0,95
0,95
0,92
0,90
0,88
0,88
0,85
0,83
Heä soá hieäu chænh doøng ñònh möùc khi ñoä saâu choân caùp thay ñoåi.
Rating factors for depth of laying
Ñoä saâu ñaët caùp
Depth of laying
(m)
600/1000 V
Caùp moät loõi
(Single core)
Caùp nhieàu loõi
(Multicore )
0,50 1,00 1,00
0,60 0,98 0,99
0,80 0,95 0,96
1,00 0,93 0,98
1,25 0,91 0,96
1,50 0,89 0,95
1,75 0,88 0,94
2,00 0,87 0,93
2,50 0,86 0,92
3,00 hoaëc hôn
(3,00 or more)
0,85 0,91
Ñoä saâu choân caùp tính töø taâm cuûa oáng ñôn chöùa caùp hay taâm cuûa nhoùm oáng chöùa caùp hình 3 laù.
(Depth of laying : to centre of duct or trefoil group of ducts)
Gheùp nhieàu maïch caùp :
Doøng ñieän ñònh möùc trong caùc baûng 13,14 chæ aùp
duïng cho 1 maïch goàm 1 caùp nhieàu loõi hoaëc goàm 2,3
caùp moät loõi. Khi soá maïch nhieàu hôn thì doøng ñònh
möùc phaûi ñöôïc hieäu chænh , heä soá hieäu chænh cho
trong baûng 19
Effect of grouping of cables
The current ratings given apply to one multicore cable, or a single
set of single core cables forming a circuit. When two or more
circuits are laid in close proximity the ratings of the cables must be
reduced by the group rating factors given on the table 19

11
Heä soá hieäu chænh doøng ñònh möùc cho caùc maïch cuûa caùp 1 loõi , ñaët theo hình ba laù hay trong oáng ñôn tuyeán
Group rating factores for circuits of single core cables, in trefoil single way ducts, horizontal formation
Soá maïch
(Number
of circuits)
(Touching)
0,45 0,6
2 0,87 0,91 0,93
3 0,78 0,84 0,87
4 0,74 0,81 0,85
5 0,70 0,79 0,83
6 0,69 0,78 0,82
Daõy heä soá hieäu chænh doøng ñònh möùc cuûa caùp nhieàu loõi trong oáng ñôn tuyeán treân maët phaúng ngang
Group rating factors for Multicore cables insingle way ducts horizontal formation
Soá oáng cuûa nhoùm
(Number
of ducts in group)
(Touching)
0,3 0,45 0,6
2 0,90 0,93 0,95 0,96
3 0,83 0,88 0,91 0,93
4 0,79 0,85 0,89 0,92
5 0,75 0,83 0,88 0,91
6 0,73 0,82 0,87 0,90
I.1.2/ Ñoä suït aùp:
Moät yeáu toá quan troïng khaùc phaûi xem xeùt khi choïn
côõ caùp laø ñoä suït aùp do toån hao treân caùp.
Ñoä suït aùp phuï thuoäc vaøo:
- Doøng ñieän taûi
- Heä soá coâng suaát
- Chieàu daøi caùp
- Ñieän trôû caùp
- Ñieän khaùng caùp
IEE 522-8 quy ñònh ñoä suït aùp khoâng ñöôïc vöôït quaù
2.,5% ñieän aùp danh ñònh
Vôùi maïch 1 pha 220V ñoä suït aùp cho pheùp 5.5V
Vôùi maïch 3 pha 380V ñoä suït aùp cho pheùp 9.5V.
Khi suït aùp lôùn hôn möùc cho pheùp thì khaùch haøng
phaûi choïn caùp coù tieát dieän ruoät daãn lôùn hôn.
I.1.2/ Voltage drop
Another important factor for the determination of the conductor size is
the voltage drop. The voltage drop of the cable at a given current is
caused by losses in the cable. In case of a too high voltage drop, it is
necessary to choose a bigger conductor size. The voltage drop in a
cable denotes the difference in voltage at the beginnining and at the
end of the cable. It depends on :
- The current carried
- The power factor
- The length of the cable
- The resistance of cable
- Reactance of the cable
The permissible voltage drop is usually stated as a percentage of the
circuit voltage. According to IEE regulation 522-8, it is stipulated that
the total voltage drop for any particular cable run must be such that
the voltage drop in the circuit of which the cable forms a part does not
exceed 2,5% of the nominal voltage.
For single phase circuit 220V, maximum voltage drop is 5,5V
For three phase circuit 380V, maximum voltage drop is 9,5V
spacing
spacing

12
Choïn caùp döïa vaøo ñoä suït aùp vaø doøng ñieän ñònh
möùc
Thöôøng thì heä soá coâng suaát cuûa taûi khoâng ñöôïc
bieát neân thoâng thöôøng giaû ñònh tröôøng hôïp xaáu
nhaát luùc hscs =1 vaø ruoät daãn laøm vieäc ôû nhieät ñoä
toái ña cho pheùp. Khi ñoù:
V=Vd x I x L
Vôùi V : ñoä suït aùp
Vd : ñoä suït aùp gaàn ñuùng mV/A/m
I : doøng ñieän pha (A)
L : chieàu daøi caùp (m)
Selection of cable based on voltage drop and current.
Since the actual power factor of the load is usually not known, the most
practical approach to the question of the voltage drop is to assume the
worst conditions, i.e power factor equal to one and the conductor is at
maximum operating temperature. The voltage drop values given in the
tables are based on these assumptions.
V=Vd x I x L
Where V : Voltage drop
Vd : Approximate Voltage drop mV/A/m
I : Current in Ampere per phase that the cable are to carry
L : Route length in metres
Duøng baûng :
Ví duï 1: Xem xeùt moät ñoaïn caùp treân khoâng loaïi
AVV/SWA 4 loõi , daøi 200m, mang taûi 100A, 3
pha, 415 V, 50Hz
Ta coù Vd I L  10400
Neân Vd 
100200
10400
x
Vd  0,52
Choïn trong baûng 1coät 9 seõ ñöôïc loaïi caùp 150m2
,
taûi doøng ñieän 100A, coù ñoä suït aùp V= 0,45
Using tables
Exemple: Consider a route of 200 metres of cable to be installed in air,
and to carry 100 ampers load, the supply voltage being 415 V, three
phase 50Hz, and the cable to be AVV/ SWA.
Vd I L  10400
Vd 
100200
10400
x
Vd  0,52
Select a cable from Table 1such that the Vd from column 9 is equal to
or less than the current. It will be seen that this value is 052 giving a
cable size of 150 mm2
.
Duøng ñoà thò :
a) Ñieän aùp cung caáp laø 240/415 V
Ví duï 1 : Vôùi ví duï treân vaø duøng ñoà thò hình 2, vôùi
giaù trò doøng ñieän taûi 100A vaø chieàu daøi caùp 200m
seõ choïn ñöôïc caùp coù tieát dieän 150 mm2
Using selection guides
a) 240/415 V supply
Example 1: Using the "Size selection guide" Figure 2 and taking the
same example as previously, the values of current (100 amps) and route
length (200 metres) indicate that a 150 mm2
conductor is required.
Although the example mentions cables in air, this size would be
required under any conditions of installation (since the current/route
length location point is not within the shaded area of the chart).
Ví duï 2 : Xeùt 1 ñoaïn caùp CVV/SWA 4 loõi , daøi
110m., taûi doøng ñieän 300A , 3 pha 415V, 50Hz
- Khi caùp choân tröïc tieáp trong ñaát : Ñoà thò ôû
hình 4 chæ ra côõ caùp phaûi laø 150mm2
- Khi caùp ñi trong oáng : do giao ñieåm giöõa doøng
ñieän vaø chieàu daøi caùp naèm trong vuøng maøu
xaùm neân khi xem baûng 14, seõ thaáy côõ caùp
150mm2
chæ taûi ñöôïc doøng ñieän 292A. Vì theá
khaùch haøng phaûi choïn côõ caùp 185mm2
ñeå taûi
doøng ñieän 300A
b) Khi ñieän aùp cung caáp khaùc 240/ 415 V
Caùc ñoà thò chæ ñöôïc thieát laäp ñoái vôùi ñieän aùp
240/415V, vì vaäy khi ñieän aùp cung caáp khaùc giaù
trò naøy thì phaûi nhaân chieàu daøi caùp vôùi heä soá cho
trong baûng döôùi ñaây vaø sau ñoù môùi duøng caùc ñoà
thò thieát laäp cho ñieän aùp 240/415 V.
Example 2: Consider a route of 110 metres of cable carrying 300
amps, the supply voltage being 415volts, three phase 50Hz, the cable to
be four core copper PVC/SWA/PVC.
- Direct in ground: from figure 4 the values of current (300 amps)
and route length (110 m) indicate that 150 mm2
conductor size will
be required.
- In single way duct: but the current/route length location point falls
within the shaded area of the chart, it is therefore necessary to check
for the current carrying capability of 150 mm2
when in ducts from
Table 14 , which shows that this size will only carry 292 amps.
Therefore it is necessary to specify a 185 mm2
conductor size to be
capable of carrying the 300 amp current.
b) Supply voltages other than 240/415V
the cable selection guides are based on a voltage of 240/415V, but can
easily be adapted for other voltages by the application of a
multiplication factor to the actual route length, and then using this
notional route length for the selection of the conductor size from the
guides
Ñieän aùp (Voltage) 220/380 V 230/400 V 255/440 V
Heä soá nhaân
(Multiplying factor)
1,09 1,04 0,96

13
Ví duï : Xem xeùt moät ñoaïn caùp ruoät nhoâm , giaùp
sôïi theùp baûo veä (AVV/SWA) , 4 loõi, daøi 100m , taûi
doøng ñieän 150A, 3 pha, 380V, 50Hz, caùp choân
trong ñaát.
Vì giaù trò ñieän aùp cung caáp laø 380V neân ta nhaân
chieàu daøi thöïc cuûa caùp (100m) vôùi heä soá cho trong
baûng 21 (1,09) ta coù :
Chieàu daøi giaû ñònh = 100 x 1,09 = 109 m
Theo hình 2 , vôùi doøng taûi 150A, chieàu daøi giaû
ñònh 109m seõ cho caùp coù tieát dieän 120 mm2
.
Example : Consider a route length of 100 metres of cable carrying 150
amps, the supply voltage being 380 volts, three phase 50Hz, and the
cable to be four core SAC PVC/SWA/PVC installed direct in the
ground.
Since the supply voltage is 380V, multiply the actual route lenth (100m)
by the factor given in the table 21 (1,09)
Notional route length = 100 x 1,09 = 109 m
From figure 2 the values of the current (150 amps) and the notional
route length (109m) indicate that 120 mm2
conductor size will be
required.
I.1.3/ Doøng ñieän ngaén maïch
Moät thoâng soá quan troïng nöõa aûnh höôûng ñeán vieäc
choïn tieát dieän ruoät daãn laø doøng ñieän ngaén maïch toái
ña cho pheùp . Doøng ñieän ngaén maïch toái ña cho pheùp
cuûa caùp caùch ñieän PVC ñieän aùp ñeán 1 kV ñöôïc tính
theo coâng thöùc ôû baûng 22 vaø ñöôïc dieãn giaûi treân caùc
hình 5,6.
I.1.3/ Short circuit current
Another important factor for the determination of the conductor size is
the maximum allowable current during a short circuit.
The maximum permissible short circuit current of PVC cables up to
1kV can be calculated with the following formulas. In table 22 and
illustrated in fig 5,6.
Côõ caùp
(Cable type)
Ruoät daãn
(Conductor)
Ñoä taêng nhieät ñoä
Temperature rising
(0
C)
Doøng ñieän ngaén maïch toái ña
Max.short circuit current
(A)
PVC Nhoû hôn hoaëc baèng 300 mm2
Up to 300 mm2
Ñoàng (Copper) 70-160 115 S t
-1/2
Nhoâm (Aluminium) 70-160 76 S t
-1/2
Lôùn hôn 300 mm2
Over 300 mm2
Ñoàng (Copper) 70-140 103 S t
-1/2
-1/2
S : Tieát dieän ruoät daãn (Conductor area, mm2
)
t : Thôøi gian ngaén maïch (Short circuit duration , seconds)

14
I.2 CAÙP ÑIEÄN LÖÏC CAÙCH ÑIEÄN XLPE
I.2.1/ Doøng ñieän ñònh möùc vaø ñoä suït aùp:
I.2.1.1/ Caùp treân khoâng
I.2/ XLPE INSULATED POWER CABLE
I.2.1/ Current rating and voltage drop
II.2.1.1/ Cables installed in air
Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa caùp ruoät ñoàng, caùch ñieän XLPE, voû PVC, khoâng giaùp baûo veä, laép treân khoâng
Current ratings and Voltage drop for Copper conductors, XLPE insulated, unarmoured, PVC oversheathed cables,
Installed in air
Baûng 23 ( Table 23)
Tieát
dieän
ruoät
daãn
Nom.
area
of
cond.
Caùp 1 loõi ( Single core cable ) Caùp nhieàu loõi ( Multicore cable )
2 caùp 1 loõi tieáp
xuùc
2-single core
Touching
3 caùp 1 loõi tieáp
xuùc
3-single core
Touching
3 caùp 1loõi ñaët
theo hình 3 laù
3-single core
Trefoil
caùch khoaûng theo
maët phaúng ngang
3-single core
Spaced
Horizontal
caùch khoaûng theo
maët phaûng ñöùng
3-single core
Spaced Vertical
Caùp 2 loõi
2 Loaded
conductor
Caùp 3 loõi
3 Loaded
conductor
A B C D E F G
Doøng
ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop
per amp
per metre
Doøng
ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop
per amp
per metre
Doøng
ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop
per amp
per metre
Doøng
ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop
per amp
per metre
Doøng
ñieän
ñònh möùc
Current ratings
Doøng
ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop
per amp
per metre
Doøng
ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop
per amp
per metre
mm2
A mV A mV A mV A mV A A mV A mV
1,5 28 30,86 25 26,73 24 26,73 29 26,73 28 26 29 23 27.7
2,5 37 18,90 34 16,37 33 16,37 39 16,37 38 36 18.0 32 17.3
4 52 11,76 44 10,19 43 10,19 54 10,19 53 49 11.6 42 11
6 66 7,86 55 6,81 52 6,81 68 6,81 67 63 7.7 54 6.9
10 91 4,67 79 4,04 75 4,04 93 4,05 92 86 4.6 75 4.1
16 118 2,95 110 2,55 107 2,55 120 2,56 119 115 2,9 100 2,6
25 161 1,87 141 1,62 135 1,62 182 1,63 161 149 1,9 127 1,6
35 200 1,35 176 1,17 169 1,17 226 1,19 201 185 1,3 157 1,2
50 242 1,01 215 0,88 207 0,87 275 0,90 246 225 1,0 192 0,87
70 310 0,71 279 0,62 268 0,61 353 0,65 318 289 0,70 246 0,61
95 377 0,52 341 0,45 328 0,45 430 0,50 389 352 0,52 298 0,45
120 437 0,43 399 0,38 382 0,37 500 0,42 454 410 0,42 346 0,36
150 504 0,36 462 0,33 443 0,32 577 0,37 527 473 0,35 399 0,30
185 575 0,30 531 0,28 509 0,26 661 0,33 605 542 0,29 456 0,25
240 679 0,25 631 0,24 604 0,22 781 0,29 719 641 0,24 538 0,21
300 783 0,22 731 0,21 699 0,20 902 0,28 833 741 0,21 620 0,19
400 940 0,20 880 0,20 839 0,17 1085 0,26 1008 - - - -
500 1083 0,19 1006 0,18 958 0,16 1253 0,25 1169 - - - -
630 1254 0,18 1117 0,17 1077 0,15 1454 0,25 1362 - - - -
800 1460 0,17 1262 0,17 1152 0,15 1696 0,24 1595 - - - -
1000 1683 0,16 1432 0,16 1240 0,14 1958 0,24 1847 - - - -
Nhieät ñoä khoâng khí 300
c (Ambient temperature 300
C)
Nhieät ñoä ruoät daãn toái ña 900
c ( Maximum Conductor temperature 900
C)
Ghi chuù :
Heä soá hieäu chænh khi gheùp nhoùm cho caùch laép töø A ñeán E xem baûng 24
Heä soá hieäu chænh khi gheùp nhoùm cho caùch laép G , F xem baûng 25
d1 : khoaûng xa töôøng khoâng nhoû hôn ñöôøng kính caùp
d2 : toái thieåu 0,3 laàn ñöôøng kính caùp
Note:
Group installation correction factor for methods A to E. please reter to Table 24
Group installation correction factor for methods F, G. please reter to Table 25
Correction factors for ambient air temperature other than 300
C, please refer to Table 26
d1 : Clearance to wall not less than one cable diameter
d2 : Minimum 0,3 times the diameter of cable.

15
Heä soá hieäu chænh doøng ñieän ñònh möùc khi gheùp nhoùm nhieàu maïch caùp 1 loõi
Ñeå duøng cuøng baûng 23 cho caùp 1 loõi treân khoâng khi laép theo caùch töø A ñeán E
Correction factors for Groups of more than one circuit of Single core Cables
To be used in conjunction with current ratings in Table 23 for Single core cables in free air for installation methods A to E
Caùch laép ñaët (Xem ghi chuù 1)
Installation method (See note 1)
Soá maïch 3 pha ( Ghi chuù 4)
Number of three-phase circuits (Note 4)
Söû duïng heä soá nhaân
ñeå hieäu chænh doøng
ñònh möùc cho
Use as a multiplier
to rating for
Soá khay
Numbers
of trays
1 2 3
Khay khoâng ñuïc loã
(ghi chuù 2)
Unperforated trays
(Note 2)
H
1 0,95 0,90 0,85
3 caùp ñaët ttheo maët
ngang
Three cables in
Horizontal
formation
2 0,92 0,85 0,80
3 0,90 0,80 0,75
Khay coù ñuïc loã
(ghi chuù 2)
Perforated trays
(Note 2)
J
1 0,95 0,90 0,85
2 0,95 0,85 0,80
3 0,90 0,85 0,80
Khay coù ñuïc loã naèm
ñöùng
( ghi chuù 3)
Vertical perforated
trays (Note 3)
K
1 0,95 0,85 - 3 caùp ñaët theo maët
ñöùng
Three cables in
Vertical formation2 0,90 0,85 -
Thang treo (ghi chuù 2)
Ladder supports
cleats, etc (Note 2)
L
1 1,00 0,95 0,95 3 caùp ñaët theo maët
ngang
Three cables in
Horizontal
formation
2 0,95 0,90 0,90
3 0,95 0,90 0,85
(ghi chuù 2)
Unperforated trays
(Note 2)
H
1 1,00 0,95 0,95
3 caùp ñaët theo hình
3 laù
Three cables in
Trefoil formation
2 0,95 0,90 0,85
3 0,95 0,90 0,85
(ghi chuù 2)
Perforated trays
(Note 2)
J
1 1,00 1,00 0,95
2 0,95 0,95 0,90
3 0,95 0,90 0,85
Khay coù ñuïc loã naèm
ñöùng
( ghi chuù 3)
Vertical perforated
trays (Note 3)
K
1 1,00 0,90 0,90
2 1,00 0,90 0,85
Thang treo
( ghi chuù 2)
Ladder supports
cleats, etc
(Note 2)
L
1 1,00 1,00 1,00
2 0,95 0,95 0,95
3 0,95 0,95 0,90
Ghi chuù :
1)Heä soá hieäu chænh duøng cho moät lôùp caùp moät loõi (hoaëc 1 nhoùm caùp hình 3 laù ). Khi caùp laép ñaët nhieàu hôn moät lôùp doøng ñieän ñònh
möùc giaûm ñaùng keå vaø phaûi tính laïi.
2)Heä soá hieäu chænh duøng khi khoaûng caùch giöõa caùc khay naèm ngang laø 300mm. Heä soá naøy seõ giaûm khi khoaûng caùch giaûm.
3)Heä soá hieäu chænh duøng vôùi khoaûng caùch giöõa caùc khay khi ñaët ñöùng, ñoái löng nhau laø 225mm. Heä soá naøy seõ giaûm khi khoaûng
caùch naøy giaûm
4)Khi moãi pha goàm nhieàu sôïi caùp maéc song song, thì 3 sôïi caùp cuûa 3 pha phaûi ñöôïc xem nhö moät maïch khi aùp duïng heä soá hieäu
chænh trong baûng naøy.
Note:
1)Factors are given for single layers of cables ( or trefoil groups) as shown in the tables and do NOT apply when cables are installed
in more than one layer touching each other Values for such installations may be significantly lower and must be determined by an
appropriate method
2)Values are given for a vertical spacing between trays of 300 mm. For closer spacing the factors should be reduced.
3)Values are given for a horizontal, spacing between trays of 225 mm with trays mounted back to back. For closer spacing the
factors should be reduced
4)For circuits having more than one cable in parallel per phase, each set of three conductors should be considered as a circuit for
the purposes of this table.

16
Heä soá hieäu chænh doøng ñieän ñònh möùc khi gheùp nhoùm nhieàu maïch caùp nhieàu loõi
Ñeå duøng cuøng baûng 23 cho caùp nhieàu loõi treân khoâng khi laép theo caùch F vaø G
Correction factors for Groups of more than one circuit of Multicore Cables
To be used in conjunction with current ratings in Table 23 for Multicore cables in free air for installation methods F& G
Caùch laép ñaët (Xem ghi chuù 1)
Installation method (See note 1)
Soá khay
Numbers of
trays
Soá caùp
Number of cable
1 2 3 4 6 9
(ghi chuù 2)
Unperforated trays
(Note 2)
M
1 0,95 0,85 0,80 0,75 0,70 0,70
2 0,95 0,85 0,75 0,75 0,70 0,65
3 0,95 0,85 0,75 0,70 0,65 0,60
1 1,00 0,95 0,95 0,95 0,90 -
2 0,95 0,95 0,90 0,90 0,85 -
3 0,95 0,95 0,90 0,90 0,85 -
(ghi chuù 2)
Perforated trays
(Note 2)
N
1 1,00 0,90 0,80 0,80 0,75 0,75
2 1,00 0,85 0,80 0,75 0,75 0,70
3 1,00 0,85 0,80 0,75 0,70 0,65
1 1,00 1,0 1,00 0,95 0,90 -
2 1,00 1,0 0,95 0,90 0,85 -
3 1,00 1,0 0,95 0,90 0,85 -
thaúng ñöùng
( ghi chuù 3)
Vertical perforated
trays
(Note 3)
O
1 1,00 0,90 0,80 0,75 0,75 0,70
2 1,00 0,90 0,80 0,75 0,70 0,70
1 1,00 0,90 0,90 0,90 0,85 -
2 1,00 0,90 0,90 0,85 0,85 -
Thang treo
( ghi chuù 2)
Ladder supports
cleats, etc
(Note 2)
P
1 1,00 0,85 0,80 0,80 0,80 0,80
2 1,00 0,85 0,80 0,80 0,75 0,75
3 1,00 0,85 0,80 0,75 0,75 0,70
1 1,00 1,00 1,00 1,00 1,00 -
2 1,00 1,00 1,00 0,95 0,95 -
3 1,00 1,00 0,95 0,95 0,95 -
Ghi chuù :
1) Heä soá hieäu chænh duøng cho moät lôùp caùp. Khi caùp laép ñaët nhieàu hôn moät lôùp doøng ñieän ñònh möùc giaûm ñi ñaùng keå vaø phaûi
caùch khaùc ñeå tính.
2) Heä soá hieäu chænh tính vôùi khoaûng caùch ñöùng giöõa caùc khay naèm ngang laø 300mm. Heä soá naøy seõ giaûm khi khoaûng caùch naøy
giaûm.
3) Heä soá hieäu chænh tính vôùi khoaûng caùch giöõa caùc khay khi ñaët ñöùng, ñoái löng nhau laø 225mm. Heä soá naøy seõ giaûm khi
khoaûng caùch naøy giaûm
Note:
1) Factors apply to single layer groups of cables as shown above and do NOT apply when cables are installed in more than one
layer touching each other Values for such installations may be significantly lower and must be determined by an appropriate
method
2) Values are given for a vertical spacing between trays of 300 mm. For closer spacing the factors should be reduced.
3) Values are given for a horizontal, spacing between trays of 225 mm with trays mounted back to back. For closer spacing the
factors should be reduced

17
Heä soá hieäu chænh doøng ñieän ñònh möùc khi nhieät ñoä khoâng khí thay ñoåi
Correction factors for ambient air temperature other than 300
C
Nhieät ñoä khoâng khí
Ambient temperature 0
C
10 15 20 25 35 40 45 50 55 60 65 70 75 80
Correction factor
1,15 1,12 1,08 1,04 0,96 0,91 0,87 0,82 0,76 0,71 0,65 0,58 0,50 0,41
I.2.1.2/ Caùp choân trong ñaát: II.1.1.2/ Cables laid direct in ground:
Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa caùp ruoät ñoàng, caùch ñieän XLPE, voû PVC coù giaùp baûo veä, choân trong ñaát
Current ratings and Voltage drop for Copper conductors, XLPE insulated, armoured, PVC oversheathed cables,
Tieát dieän ruoät
daãn
Nom. area of
cond.
Caùp 1 loõi , giaùp sôïi nhoâm
(Single core cable, Aluminium wire armoured )
Caùp nhieàu loõi, giaùp sôïi theùp
( Multicore cable, Steel wire armoured )
2 caùp ñaët tieáp xuùc trong löôùi
ñieän xoay chieàu 1 pha
Two cables touching,
single-phase (ac)
3 caùp tieáp xuùc nhau theo hình
3 laù , 3 pha
Three cables trefoil touching,
3-phase
Caùp 2 loõi , löôùi ñieän xoay
chieàu 1 pha
Two core cable ,
single-phase (ac)
Caùp 3 hay 4 loõi
Three or four core Cable
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per
metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop
per amp per
metre
Doøng
ñieän ñònh
möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
mm2
A mV A mV A mV A mV
16 142 2,9 135 2,57 140 2,90 115 2,60
25 185 1,88 172 1,55 180 1,90 150 1,60
35 226 1,27 208 1,17 215 1,30 180 1,20
50 275 0,99 235 0,86 255 1,00 215 0,87
70 340 0,70 290 0,61 315 0,70 265 0,61
95 405 0,53 345 0,46 380 0,52 315 0,45
120 460 0,43 390 0,37 430 0,42 360 0,36
150 510 0,37 435 0,32 480 0,35 405 0,30
185 580 0,31 490 0,27 540 0,29 460 0,25
240 670 0,26 560 0,23 630 0,24 530 0,21
300 750 0,24 630 0,21 700 0,21 590 0,19
400 830 0,21 700 0,19 - - - -
500 910 0,20 770 0,18 - - - -
630 1000 0,19 840 0,17 - - - -
800 1117 0,18 931 0,16 - - - -
1000 1254 0,17 1038 0,15 - - - -
Thoâng soá laép ñaët cô sôû :
Cm/W
C
Ñoä saâu choân caùp : 0,5m
C
Soil thermal resistivity 1.2 0
C m/W
C
Dep th of lay ing 0. 5 metre
C.
Heä soá hieäu chænh doøng ñieän ñònh möùc khi nhieät ñoä ñaát thay ñoåi cho trong baûng 28
Heä soá hieäu chænh doøng ñieän ñònh möùc khi gheùp nhoùm cho trong baûng 29
Correction factors for ground temperatures other than 150
C, refer to Table 28
For group correction factors, please refer to Table 29
Heä soá hieäu chænh doøng ñònh möùc khi nhieät ñoä ñaát thay ñoåi
Correcion factors for ground temperatures other than 150
C
C)
10 15 20 25 30 35 40 45 50
Correction factors
1,03 1,00 0,97 0,93 0,89 0,86 0,82 0,76 0,72

18
Heä soá hieäu chænh doøng ñieän ñònh möùc khi gheùp nhoùm
Group correcion factors- to be used in conjunction with ratings for cables in table 29
Khoaûng hôû giöõa 2 caùp
Cable to cable clearance (a)
Soá maïch
(Number
of circuits)
Khoâng hôû
(caùp tieáp xuùc)
Nil
(cables touching)
Khoaûng hôû
baèng ñöôøng
kính moät caùp
a= One cable
diameter
0,215 m 0,25 m 0,5 m
2 0,75 0,80 0,85 0,90 0,90
3 0,65 0,70 0,75 0,80 0,85
4 0,60 0,60 0,70 0,75 0,80
5 0,55 0,55 0,65 0,70 0,80
6 0,50 0,55 0,60 0,70 0,80
i.2.1.3/ Caùp ñi trong oáng ñôn tuyeán choân trong ñaát II.1.1.3/ Cable run in single way ducts
Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa caùp ruoät ñoàng, caùch ñieän XLPE, voû PVC coù giaùp baûo veä, ñi trong oáng choân trong ñaát
Current ratings and Voltage drop for Copper conductors, XLPE insulated, armoured, PVC oversheathed cables,
Run in single way ducts
Tieát dieän ruoät
daãn
Nom. area of
cond.
Caùp 1 loõi , giaùp sôïi nhoâm
(Single core cable, Aluminium wire armoured )
Caùp nhieàu loõi, giaùp sôïi theùp
( Multicore cable, Steel wire armoured )
2 caùp : oáng ñaët tieáp xuùc
Two cables: ducts touching
3 caùp : oáng ñaët tieáp xuùc theo
hình 3 laù
Three cables : ducts touching,
trefoil
Caùp 2 loõi
Two core cable
Caùp 3 hay 4 loõi
Three or four core Cable
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per
metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop
per amp per
metre
Doøng
ñieän ñònh
möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per metre
mm2
A mV A mV A mV A mV
16 140 3,0 130 2.70 115 2,90 94 2,60
25 180 2,0 170 1,80 145 1,90 125 1,60
35 215 1,4 205 1,25 175 1,30 150 1,20
50 255 1,10 235 0,93 210 1,00 175 0,87
70 310 0,80 280 0,70 260 0,70 215 0,61
95 365 0,65 330 0,56 310 0,52 260 0,45
120 410 0,55 370 0,48 355 0,42 300 0,36
150 445 0,50 405 0,43 400 0,35 335 0,30
185 485 0,45 440 0,39 455 0,29 380 0,25
240 550 0,40 500 0,35 520 0,24 440 0,21
300 610 0,37 550 0,32 590 0,21 495 0,19
400 640 0,35 580 0,30 - - - -
500 690 0,33 620 0,28 - - - -
630 750 0,30 670 0,26 - - - -
800 828 0,28 735 0,24 - - - -
1000 919 0,26 811 0,22 - - - -
Thoâng soá laép ñaët cô sôû :
Cm/W
C
Nhieät ñoä khoâng khí : 250
C
Ñoä saâu choân caùp : 0,5m
C
Soil thermal resistivity 1.2 0
C m/W
C
Ambient air temperature 25 0
C
Dep th of lay ing 0. 5 metre
C.
Heä soá hieäu chænh doøng ñieän ñònh möùc khi nhieät ñoä ñaát thay ñoåi cho trong baûng 28
Correcion factors for ground temperatures other than 150
For group correcion factors, please refer to Table 31

19
Heä soá hieäu chænh doøng ñieän ñònh möùc khi gheùp nhoùm, söû duïng ñeå hieäu chænh doøng ñònh möùc cho trong baûng 30
Caùp moät loõi
Soá maïch
(Number of
single-core
circuits of two or
three cables)
Khoaûng hôû giöõa 2 oáng - Duct to duct clearance (a)
Khoâng hôû (oáng tieáp xuùc)
Nil (ducts touching)
0,25 m 0,5 m 1,0 m
2 0,80 0,90 0,90 0,95
3 0,70 0,80 0,85 0,90
4 0,65 0,75 0,80 0,90
5 0,60 0,70 0,80 0,90
6 0,60 0,70 0,80 0,90
Caùp nhieàu loõi
Soá caùp
(Number
of cables)
Khoaûng hôû giöõa 2 oáng
Duct to duct clearance (a)
Khoâng hôû (oáng tieáp xuùc)
Nil (ducts touching)
0,25 m 0,5 m 1,0 m
2 0,85 0,90 0,95 0,95
3 0,75 0,85 0,90 0,95
4 0,70 0,80 0,85 0,90
5 0,65 0,80 0,85 0,90
6 0,60 0,80 0,80 0,90
II.1.1.4/ Caùp ñi trong oáng trong maùng vaø boù caùp
raûi treân beà maët
II.1.1.4/ Cable in conduit and trunking and
bunched cables on a surface
Doøng ñieän ñònh möùc cuûa caùp ruoät ñoàng, caùch ñieän XLPE, voû PVC giaùp baûo veä, ñi trong oáng trong maùng
Current ratings for Copper conductors, XLPE insulated, armoured, PVC oversheathed cables, Cable in conduit and trunking and
bunched cables on a surface)
Tieát dieän ruoät daãn
Nom. area of cond.
Caùp 1 loõi ñi trong oáng choân trong
töôøng
Insulated conductors in conduit in
insulating wall
Caùp 1 loõi ñi trong oáng ñaët treân töôøng
Insulated conductors in conduit on wall
Caùp nhieàu loõi ñaët treân töôøng
Multicore cable on a wall
R S T
2 sôïi caùp
2 Loaded
conductor
3 sôïi caùp
3 Loaded
conductor
2 sôïi caùp
2 Loaded
conductor
3 sôïi caùp
3 Loaded
conductor
2 sôïi caùp
2 Loaded
conductor
3 sôïi caùp
3 Loaded
conductor
mm2
A A A A A A
1,5 19 17 23 20 24 22
2,5 26 23 31 27 33 30
4 35 31 42 37 45 40
6 45 40 54 48 58 52
10 61 54 74 66 80 71
16 81 73 100 89 107 96
25 106 95 133 117 138 119
35 131 117 164 144 171 147
50 158 141 198 175 210 179
70 200 179 254 222 269 229
95 241 216 306 269 328 278
120 278 249 354 312 382 322
150 318 285 - - 441 371
185 362 324 - - 506 424
240 424 380 - - 599 500
300 486 435 - - 693 576
400 579 519 - - 860 692
500 664 595 - - 994 797
630 765 685 - - 1155 923
800 885 792 - - 1349 1074
1000 1014 908 - - 1560 1237
Nhieät ñoä khoâng khí : 300
C
Nhieät ñoä toái ña cuûa ruoät daãn laø 900
C
Ambient air temperature 30 0
C
Maximum conductor temperature : 900
C
Heä soá hieäu chænh doøng ñieän ñònh möùc khi nhieät ñoä kh6ng khí thay ñoåi cho trong baûng 28
Correcion factors for ambient temperatures other than 300
For group correcion factors, please refer to Table 33

20
Heä soá hieäu chænh doøng ñieän ñònh möùc khi gheùp nhoùm- Söû duïng ñeå hieäu chænh doøng ñieän ñònh möùc cho trong baûng 32
Item Caùch ñaët caùp
Arrangement of cables
Correction factors
Number of circuits or multicore cables
1 2 3 4 5 6 7 8 9 10 12 14 16 18 20
1
Boù caùp raûi treân maët hay ñi
trong oáng, trong maùng
Bunched on a surface or
enclosed in conduit or
trunking
1,00 0,80 0,70 0,65 0,60 0,55 0,55 0,50 0,50 0,45 0,45 0,40 0,40 0,40 0,40
2
1 lôùp caùp treân
töôøng hay neàn
nhaø
Single-layer
wall or floor
Tieáp xuùc
Touching
1,00 0,85 0,80 0,75 0,75 0,70 0,70 0,70 0,70 0,70 0,70 0,70 0,65 0,65 0,65
3
Caùch
khoaûng
Spaced
1,00 0,95 0,90 0,90 0,90 0,90 0,90 0,90 0,90 0,90 0,90 0,90 0,90 0,90 0,90
4
1 lôùp caùp döôùi
traàn nhaø
Single-layer
under ceiling
Tieáp xuùc
Touching
0,95 0,80 0,70 0,70 0,65 0,65 0,60 0,60 0,60 0,60 0,60 0,60 0,55 0,55 0,55
5
Caùch
khoaûng
Spaced
0,95 0,85 0,85 0,85 0,85 0,85 0,85 0,85 0,85 0,85 0,85 0,85 0,85 0,85 0,85
Löu yù :
1) Heä soá ñieàu chænh aùp duïng cho cho caùp mang taûi ñeàu nhau
2) Khi khoaûng caùch ngang cuûa hai sôïi caùp keà nhau vöôït quaù hai laàn ñöôøng kính caùp thì khoâng caàn giaûm baèng heä soá hieäu chænh
3) Cuøng 1 heä soá ñieàu chænh cho:
- nhoùm 2 hay 3 caùp 1 loõi.
- Caùp nhieàu loõi.
4) Neáu gheùp nhoùm n sôïi caùp 1 loõi thì xem nhö laø gheùp nhoùm n/2 maïch 2 sôïi caùp hoaëc n/3 maïch 3 sôïi caùp.
Note:
1) These factors are applicable to uniform groups of cables. equally loaded
2) Where horizontal clearance between adjacent cables exceeds twice their overall diameter, no reduction factor need be applied
3) The same correction factors are applied to:
- groups of two or three single-core cables
- multicore cables.
4) If a group consists of n loaded single-core cables it may either be considered as n/2 circuits of two loaded conductors or n/3
circuits of three loaded conductors.
Ruoät daãn
Conductor
Ñoä taêng nhieät ñoä
Temperature rising
(0
C)
Doøng ñieän ngaén maïch toái ña
Max.short circuit current
(A)
XLPE Ñoàng (Copper) 90-250 143 S t
-1/2
-1/2
S : Tieát dieän ruoät daãn (Conductor area, mm2
)
t : thôøi gian ngaén maïch ( Short circuit duration , seconds)
I.2.2/ Doøng ñieän ngaén maïch cuûa caùp boïc XLPE I.2.2/ Short circuit current OF XLPE INSULATED CABLE

21
II/ CAÙP ÑIEÄN KEÁ
II.1/ CAÙCH ÑIEÄN PVC
II/ SERVICE ENTRANCE CABLE
II.1/ PVC INSULATED
Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa caùp ñieän keá caùch ñieän PVC, voû PVC- kyù hieäu DKCVV
Current ratings and Voltage drop for Copper conductors, PVC insulated, PVC sheathed service entrance cable
Gioáng baûng 4phaàn caùp ñieän löïc boïc PVC.
II.2/ CAÙCH ÑIEÄN XLPE II.2/ XLPE INSULATED
Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa caùp ñieän keá caùch ñieän XLPE, voû PVC hoaëc HDPE –kyù hieäu DKCXV, DKCXE
Current ratings and Voltage drop for Copper conductors, PVC insulated, PVCor HDPE sheathed service entrance cable
Gioáng baûng 23,coät F,G.
III/ CAÙP ÑIEÀU KHIEÅN
III.1/ CAÙCH ÑIEÄN PVC
III/ CONTROL CABLES
III.1/ PVC INSULATED
Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa caùp ñieàu khieån, caùch ñieän PVC, voû PVC-kyù hieäu DVV
Current ratings and Voltage drop for Copper conductors, PVC insulated, PVC sheathed, Control Cables
Côõ caùp
Conductor size
Doøng ñieän ñònh möùc
Current ratings
Ñoä suït aùp
Approximate volt drop per
amp per metre
mm2
A mV
Caùp treân khoâng ( nhieät ñoä khoâng khí laø 300
C, nhieät ñoä ruoät daãn toái ña laø 700
C)
In air ( ambient temperature 300
C, maximum conductor temperature 700
C)
1,5 18 25
2,5 25 15
4 33 9,5
6 42 6,4
10 58 3,8
16 77 2,4
III.2/ CAÙCH ÑIEÄN XLPE III.2/ XLPE INSULATED
Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa caùp ñieàu khieån, caùch ñieän XLPE, voû PVC-kyù hieäu DXV
Current ratings and Voltage drop for Copper conductors, XLPE insulated, PVC sheathed, Control Cables
Côõ caùp
Conductor size Doøng ñieän ñònh möùc
Current ratings
Ñoä suït aùp
Approximate volt drop
per amp per metre
mm2
A mV
Caùp treân khoâng ( nhieät ñoä khoâng khí laø 300
C, nhieät ñoä ruoät daãn toái ña laø 900
C)
In air ( ambient temperature 300
C, maximum conductor temperature 900
C)
1,5 22 27
2,5 31 17
4 42 10
6 54 6,8
10 74 4,1
16 99 2,6
IV/ CAÙP MULTIPLEX IV/ MULTIPLEX CABLE
Doøng ñieän ñònh möùc cuûa caùp Multiplex, boïc PVC hoaëc XLPE
Current ratings for Nonsheathed, PVC or XLPE insulated Multiplex Cable
Côõ caùp
Conductor
size
Duplex Triplex Quadruplex
CV AV CX AX CV AV CX AX CV AV CX AX
mm2
A A A A A A A A A A A A
4 37 - 49 - 33 - 45 - 31 - 40 -
6 47 - 63 - 43 - 60 - 41 - 56 -
10 65 52 86 68 59 47 80 62 56 44 76 58
16 87 70 115 92 79 63 110 78 76 61 108 78
25 114 91 149 119 104 83 135 105 101 80 130 105
35 140 112 185 148 129 103 169 125 125 100 164 125
50 189 151 225 180 167 133 207 150 151 120 202 150
70 215 172 289 230 214 171 268 185 192 153 262 185

22
V/ DAÂY ÑIEÄN LÖÏC V/ PVC OR XLPE INSULATED - NONSHEATHED CABLE
Doøng ñieän ñònh möùc vaø ñoä suït aùp cuûa daây ñieän löïc, caùch ñieän PVC hoaëc XLPE
Current ratings and Voltage drop for Nonsheathed, PVC or XLPE insulated Cable
Côõ caùp
Conductor
size
Daây ñieän löïc boïc PVC
Nonsheathed, PVC insulated Cable
Daây ñieän löïc boïc XLPE
Nonsheathed, XLPE insulated Cable
CV AV CX AX
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop
per amp per
metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop per
amp per
metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop
per amp per
metre
Doøng ñieän
ñònh möùc
Current
ratings
Ñoä suït aùp
Approximate
volt drop
per amp per
metre
mm2
A mV A mV A mV A mV
1,0 15 38 - - 20 40 - -
1,5 20 25 - - 26 31 - -
2,5 27 15 - - 36 19 - -
4 37 9,5 - - 49 12 - -
6 47 6,4 - - 63 7,9 - -
10 65 3,0 52 - 86 4,7 68 -
16 87 2,4 70 3,9 115 2,9 92 4,8
25 114 1,55 91 2,5 149 1,9 119 3,1
35 140 1,10 112 1,8 185 1,35 148 2,2
50 189 0,82 151 1,35 225 0,87 180 1,4
70 215 0,57 172 0,92 289 0,62 230 0,98
95 260 0,42 208 0,67 352 0,47 281 0,74
120 324 0,35 259 0,54 410 0,39 328 0,60
150 384 0,29 307 0,45 473 0,33 378 0,49
185 405 0,25 324 0,37 542 0,28 430 0,41
240 518 0,21 414 0,30 641 0,24 512 0,34
300 570 0,19 456 0,25 741 0,21 592 0,29
400 660 0,17 528 - 830 0,195 - -
500 792 0,16 633 - 905 0,180 - -
630 904 0,15 723 - 1019 0,170 - -
800 1030 0,15 824 - 1202 - - -
Nhieät ñoä khoâng khí laø 300
C
Nhieät ñoä ruoät daãn laø 700
C
Ambient temperature 300
C
Maximum conductor temperature 700
C

23
VI/ DAÂY ÑIEÄN BOÏC NHÖÏA PVC VI/ PVC INSULATED WIRE
Doøng ñieän ñònh möùc cuûa daây ñieän boïc nhöïa PVC
Current ratings of PVC insulated wire
Daây ñoâi meàm, ruoät ñoàng
Flexible Copper conductor – PVC insulated wire
Daây ñôn cöùng, ruoät ñoàng hoaëc nhoâm
Solid Copper or Aluminium conductor – PVC insulated wire
Soá loõi
Num. of
core
Tieát dieän
Nom. area
of conductor
Daây ñoâi meàm
deït, meàm xoaén
VCmd , VCmx
Daây ñoâi meàm troøn, meàm
ovan, meàm oval deït
VCmt , VCmo , VCmod
Tieát dieän
Nom. area
of conductor
Ñöôøng kính sôïi
Diameter of
wire
VC
Ruoät ñoàng
Copper
conductor
VA
Ruoät nhoâm
Aluminium
conductor
mm2
A A mm2
mm A A
2 0,5 5 7 1 1,13 17 -
2 0,75 7 10 1,13 1,20 19 -
2 1,0 10 11 1,5 1,4 23 -
2 1,25 12 13 2,0 1,6 27 -
2 1,5 14 15 2,5 1,8 30 23
2 2,0 16 17 3 2,0 35 26
2 2,5 18 20 4 2,25 42 32
2 3,5 - 24 5 2,60 48 36
2 4,0 - 27 6 2,78 51 39
2 5,5 - 32 7 3,0 57 43
2 6,0 - 36
VII/ DAÂY ÑOÀNG TRAÀN XOAÉN, DAÂY
NHOÂM TRAÀN XOAÉN VAØ DAÂY
NHOÂM LOÕI THEÙP
VII/ BARE STRANDED COPPER AND ALUMINIUM
CONDUCTOR AND ALUMINIUM
CONDUCTOR STEEL REINFORCED
Doøng ñieän ñònh möùc cuûa daây ñoàng traàn xoaén, daây nhoâm traàn xoaén
Current ratings of Bare stranded copper conductor, Bare stranded aluminium conductor Baûng 40 ( Table 40)
Tieát dieän
Nom. area
of conductor
Daây ñoàng traàn xoaén
Bare stranded copper conductor
C
Daây nhoâm traàn xoaén
Bare stranded aluminium conductor
A
Doøng ñieän ñònh möùc
Current ratings
Doøng ñieän ñònh möùc ôû vuøng oân ñôùi.
Temperate Current ratings.
mm2
A A
4 50 -
6 70 -
10 95 -
14 120 -
16 130 105
25 180 135
35 220 170
38 230 182
50 270 215
60 305 225
70 340 265
80 377 276
95 415 320
100 450 340
120 485 375
125 500 390
150 570 440
185 640 500
240 760 590
300 880 680
325 943 710
400 1050 815
500 1254 980
630 1497 1170
800 1662 1330

24
ACSR
Tieát dieän
Nom. area
of conductor
Daây nhoâm loõi theùp
Aluminium conductor steel reinforced
Doøng ñieän ñònh möùc ôû vuøng oân ñôùi
Tem perate Current ratings
Doøng ñieän ñònh möùc ôû vuøng nhieät ñôùi
Tropical Current ratings
mm2
/ mm2
A A
35/ 6 175 89
50/ 8 210 105
70/ 11 265 127
95/ 16 330 145
120/ 19 375 161
150/ 24 445 173
185/ 29 510 185
240/ 39 610 199
300/ 48 690 205
330/ 43 712 -
400/ 51 835 -
450/ 40 856 -
500/ 64 940 -
560/ 38 980 -
560/ 70 990 -
680/ 85 1220 -

25
B

CTY TNHH Daây & Caùp Ñieän Vieät Nam (CADIVI) 26
C/ LAÉP ÑAËT
I/ Ñoä uoán cong laép ñaêt toái thieåu
C/ ( HANDLING)
I/ Minimum bending radius
Loaïi caùp ( Type of cable) 1 loõi
(Single core)
Nhieàu loõi
(Multi cores)
Haï theá 0,6/1 kV
(Low voltage)
Khoâng giaùp (Non armoured) 8D 6D
Giaùp baêng sôïi (Tape, wire armoured) 10D 8D
D : ñöôøng kính cuûa caùp (Overall dia. Of cable)
II/ Löïc keùo caùp toái ña cho pheùp II/ Permissible max. pulling tensile
Phöông thöùc keùo (Means of pulling)
Loaïi caùp
( Type of cable)
Coâng thöùc
(Formula)
Heä soá
(Factor)
Ñaàu keùo keïp vaøo ruoät daãn
With pulling head attached to conductor
Taát caû caùc loaïi caùp
All type of cable
P=. A
 = 50 N/mm2
( Cu- conductor)
 = 30 N/mm2
( Al- conductor)
Ñaàu keùo keïp vaøo ñaàu caùp
With pulling stocking
Caùp khoâng giaùp hoaëc giaùp baêng
Cable unarmoured or double
tape armour
P=. A
 = 50 N/mm2
( Cu- conductor)
 = 30 N/mm2
( Al- conductor)
Caùp giaùp sôïi
Wire armoured cables
P=K.d2
K=9N/mm2
P : Löïc keùo (Pulling tensile) (N)
A : Tieát dieän toång caùc ruoät daãn (Total cross sectionnal area of all conductor) (mm2
)
d : Ñöôøng kính caùp ( Diameter of cable ) (mm)
 : ÖÙng suaát keùo cuûa ruoät (Permissible tensile streng of conductor ) (N/mm2
)
III/ Aùp suaát taùc duïng leân caùp
Aùp suaát toái ña cho pheùp taùc duïng leân caùp taïi ñieåm uoán
trong khi laép ñaët laø 500kg/m
III./ Side wall pressure to cable
Permissible maximum side wall pressure to the cable at bending
point during installation is 500 kg/m
IV / Taùch voû caùp
Thao taùc caån thaän keûo hoûng lôùp caùch ñieän vaø sinh
ñaùnh thuûng caùp.
IV / Removal of sheath or tape
Special care must be taken not to harm the insulation. When
removing the sheath with a knife otherwise it may result in a
dielectric breakdown
V / Laøm saïch beà maët lôùp caùch ñieän
Phaûi laøm saïch beà maët lôùp caùch ñieän
ñeå khoâng bò phoùng ñieän taïi ñaàu noái
V/ Cleaning the surface of insulation
The surface of insulation should be cleaned to avoid a flash
over at the cable termination or joint
VI/ Xöû lyù choáng thaám nöôùc cho ñaàu noái ngoaøi trôøi
Ñaàu noái ngoaøi trôøi phaûi ñöôïc xöû lyù choáng thaám nöôùc
vaø quaán baêng caån thaän ñeå nöôùc khoâng luoàn vaøo ñaàu
caùp.
VI/ Water proof treatment for out-door termination
For out-door termination water proof treatment is necessan to
avoid the water penetrating to the cable end and special care
must be taken to apply tapes end terminals.
D / HÖÔÙNG DAÃN ÑAËT HAØNG CAÙP HAÏ THEÁ
Khi ñaët haøng xin quí khaùch vui loøng thoâng baùo cho CADIVI
nhöõng thoâng tin sau:
1. Toång chieàu daøi vaø chieàu daøi 1 tureâ.
2. Taàm ñieän aùp.
3. Soá loõi.
4. Côõ ruoät daãn vaø ruoät trung tính.
5. Vaät lieäu ruoät daãn ñoàng, nhoâm.
6. Vaät lieäu caùch ñieän.
7. Ñoän sôïi hay boïc loùt.
8. Giaùp baêng hay sôïi, nhoâm hay theùp.
9. Vaät lieäu voû.
10. Tieâu chuaån aùp duïng.
D / PURCHASING GUIDELINES
The purchaser should supply the following information at the
time of enquiry and order
1. Length of cable required and individual drum length of
important
2. Voltage designation
3. Number of cores
4. Conductor size and where applicable, size of reduced
conductor
5. Conductor material i.e copper , aluminum
6. Insulation material, i.e, PVC, XLPE
7. PP yarn or extruded bending
8. Non armour, double steel tape armour, double aluminum
tape armour, Aluminum wire armour
9. Sheath material
10. Applied standard TCVN, ASTM, IEC, BS, DIN, AS

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