Selection of Cables: Selection of cable is based on the following factors:
-
For LT Cable:
- Current carrying capacity.
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Voltage drop.
The voltage drop should not normally exceed 2 % of rated voltage. The voltage drop is calculated as follows:
For DC System or AC 2 wire system: Vd = 2 × I × R
For 3 Phase System: Vd = √3 × I × R
where Vd is the voltage drop, I is current, R is the resistance of one conductor (not lead or return).
- Environmental Condition.
- Formation and distance between cables.
-
For HT Cable:
-
Rupturing capacity.
Once rupturing capacity is known from the supply company, the HT cable size is worked out as under:
-
For 11 kV System:
- A = 14.2 × ISC × √t (For Al conductor)
- A = 9.41 × ISC × √t (For Cu conductor)
-
For 22 kV System:
- A = 16.39 × ISC × √t (For Al conductor)
- A = 10.98 × ISC × √t (For Cu conductor)
where A is the cross section area of conductor in mm², t is the fault current duration in seconds, normally taken as 0.2 seconds and ISC is the short circuit current in kA and is calculated by the formula ISC = Rupturing Capacity in MVA / (√3 × System Voltage in kV)
After selection based on rupturing capacity, current carrying capacity should be seen and higher size of the cable satisfying both the criteria should be selected.
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- Current carrying capacity.
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IMPORTANT POINTS FOR PILC CABLE LAYING:
- The cable drum should always be rolled in the direction of the arrow, if it is to be moved over a short distance.
-
Recommended depth of the trench should be:
Up to 1.1 kV: 46 to 76 cm plus radius of complete cable. 3.3 to 11 kV: 91 cm plus radius of complete cable. 22 & 33 kV: 107 cm plus radius of complete cable. - While pulling the cable before laying, the direction in which the cable is to be pulled should be first decided. If it is new laying of cable, no special precautions are required, but if it is to be connected with the existing cable, the sequence or core numbers at the running ends should be first ascertained and the new cable pulled in accordingly. This procedure is always better to avoid crossing of cores in the joint. The cable to be jointed should be laid with sufficient overlap for jointing.
-
Minimum bending radius should be as given below, wherever possible 25 % larger radius than the value given in the table should be used:
System Voltage Single Core Multi Core (Unarmoured) Multi Core (Armoured) Up to 11 kV 20 D 15 D 12 D Up to 22 kV 25 D 20 D 15 D Up to 33 kV 30 D 25 D 20 D Where D is the overall diameter of the cable.
-
Other general points to be observed are mentioned below:
- Prior to joint a proper jointing position should be selected.
- The joint hole should be of sufficient dimension for easy working.
- The depth of joint hole should be at least 31 cm below the proposed laying depth.
- The sides of the hole should be well covered with tarpaulin to prevent loose earth from falling.
- The jointing should always be carried out inside a tent.
- For jointing of higher voltage live cables, the cable should be made DEAD and earthed before commencement of the jointing. This should be confirmed by an instrument like induction coil, headphones.
- Any mistake in the identification of the proper cable will result in a fatal accident.
- While handling the insulation cleanliness is very essential. Any contamination of the insulation by dust or moisture is detrimental to the joint.
- The cable should never be exposed to atmosphere for a long time.
- In monsoon season before commencement of jointing special precaution should be taken.
- The cable seal should be examined for any damage or puncture. The paper insulation should then be tested for presence of moisture. This is done by dipping the insulation paper next to the conductor and sheath in hot cable compound of paraffin wax at a temperature between 120 to 140 °C, the presence of the moisture is indicated by formation of bubbles on the paper. Only one single strip of paper gripped by a pair or tweezers should be used. The paper removed from the cable should be handled carefully to avoid contamination. After this the insulation of cable to be jointed should be tested to check the condition of the insulation.
- Check the continuity and phasing out of the cables to be jointed. If necessary. The no. of cores normally represent the number of phases, but it should not be taken for granted.
JOINTING AND TERMINATION OF XLPE CABLES:
XLPE cable is suitable for installation in ground duct or air similar to conventional cables. It is easier to handle and install. Being lighter and of smaller dimension compared to the other power cables of the same capacity, this cable requires lesser number of supports, clamps etc when installed in the air. Unlike paper insulated cable, XLPE cable can be installed in vertical runs of unlimited difference in level. The recommended minimum bending radius for the armoured XLPE cable are:
For screened cable: | 12 D |
For unscreened cable: | 8 D |
where D is the overall diameter of the cable.
As XLPE cable insulation is highly resistant to moisture, hence jointing and termination of XLPE cable is simpler to PILC cable. Up to 3.3 kV, the cable can be terminated straightway with compression glands similar to other polymeric insulated cables. A new range of jointing and termination system has been evolved to meet the need of such cables to operate at a higher temperature, the salient feature of which is given below:
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JOINTING OF CONDUCTORS: Since the maximum permissible temperature is 250 °C for XLPE cables, soldered type joints becomes unsuitable as solder melts at much lower temperature. Welded or crimped / compression type conductor joints are therefore adopted for XLPE cables.
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INSULATION BUILD-UP: The conductor joints is insulated by lapping of EPR self-amalgamating (S.A.) tape to the required thickness. Tape in universally accepted as the most reliable material because of its resistance to water, capacity to operate at higher temperature, high dielectric strength and void free amalgamating properties.
For cables above 3.3 kV, semiconductor S.A. tape is applied on the conductor to equalize distribution of electrical stress on the conductor surface. The insulated cores are further lapped with the tape to serve as core screening. For cable up to 3.3 kV, S.A. tape is not necessary.
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STRAIGHT THROUGH JOINT: The joint assembled (with insulated core) is incapsulated in special resin cast compound.
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STRESS RELIEVED TERMINATION: The termination of cables above 3.3 kV is provided with stress cone to relieve electrical stress formed on the insulation at the point of the termination of the cable screen. S.A. tape is lapped over the insulation to the required thickness to build up the stress cone.
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INDOOR TYPE TERMINATION: Indoor type termination up to 3.3 kV is provided with stress cone but it does not require any compound for encapsulation. However, it must be protected by lapping of adhesive PVC for protection against external abuses.
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OUTDOOR TYPE TERMINATION: Outdoor type termination above 3.3 kV is provided with stress cone, but this termination is encapsulated in special resin cast compound to protect the joint from atmospheric abuses.
COLOR IDENTIFICATION OF CABLES:
It is done by colour identification of core of rubber / PVC insulated cable or of sleeve / disc to be applied to conductor or cable core. Following is adopted:
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Non-Flexible Cables & Bare Conductor for Fixed Wiring:
Function Colour Identification Earthing Green and Yellow or Green Neutral of single / three phase circuit Black Live of single phase circuit Red Phases of three phase circuit Red, Yellow, Blue Outer (positive or negative) of DC 2 wire circuit derived from 3 wire Red Positive of three wire DC Red Middle of three wire DC Black Negative of three wire DC Blue Fifth core (special purpose) in 5-core armoured PVC cable Orange -
Flexible Cables & Flexible Cords:
Function Colour Identification Live Brown Neutral Blue Earthing Green and Yellow
Ratio | Criterion | ||
---|---|---|---|
Equal Resistance | Equal current and temp. rise | Equal diameter | |
Ratio of Aluminum to Copper | |||
Area ratio | 1.61 | 1.39 | --- |
Diameter ratio | 1.27 | 1.18 | --- |
Weight Ratio | 0.48 | 0.42 | 0.30 |
Current Carrying Capacity | --- | --- | 0.78 |
Standard Copper Conductor | Continuous Current Rating | Standard Al. Conductor | |||||||
---|---|---|---|---|---|---|---|---|---|
Nominal Conductor Area | Conventional Sizes | No. & dia of wire | In conduit/casing | Bunched in air or open trench | In air/open trench | No. & dia. of wire | Nominal Conductor Area | ||
2 Single core | 2 Single core | 3 / 4 Single core | 1 / 2 core DC / AC | 3 / 4 core AC | |||||
mm² | SWG | mm | A | A | A | A | A | mm² | mm² |
1.00 | 1/18 | 1/1.12 | 4 | 4 | 4 | 4 | 4 | ||
1.25 | 3/22 | 3/0.74 | 7 | 7 | 7 | 7 | 5 | 1/1.40 | 1.5 |
2.00 | 3/20 | 3/0.91 | 10 | 10 | 9 | 10 | 7 | 1/1.80 | 2.5 |
3.00 | 7/22 | 7/0.74 | 14 | 14 | 10 | 14 | 10 | ||
14 | 14 | 12 | 14 | 10 | 1/2.24 | 4 | |||
19 | 19 | 17 | 19 | 13 | 1/2.80 | 6 | |||
4.50 | 7/20 | 7/0.91 | 19 | 19 | 17 | 19 | 14 | ||
23 | 23 | 21 | 23 | 17 | 1/3.55 | 10 | |||
6.75 | 7/18 | 7/1.12 | 25 | 25 | 22 | 25 | 17 | ||
10.0 | 7/17 | 7/1.32 | 30 | 30 | 26 | 30 | 21 | 7/1.70 | 16 |
14.5 | 7/16 | 7/1.62 | 37 | 37 | 33 | 37 | 26 | ||
41 | 41 | 41 | 41 | 29 | 7/2.24 | 25 | |||
18.5 | 19/18 | 19/1.12 | 43 | 43 | 39 | 43 | 30 | ||
48 | 48 | 43 | 48 | 33 | 7/2.50 | 35 | |||
25.0 | 19/17 | 19/1.32 | 51 | 51 | 46 | 51 | 36 | ||
63 | 63 | 57 | 63 | 43 | 7/3.00 19/1.80 | 50 | |||
40.0 | 19/16 | 19/1.62 | 67 | 61 | 67 | 47 | |||
50.0 | 19/15 | 19/1.82 | 85 | 74 | 79 | 54 | |||
92 | 82 | 81 | 57 | 19/2.24 | 70 | ||||
106 | 95 | 93 | 65 | 19/2.50 | 95 | ||||
65.0 | 19/14 | 19/2.10 | 110 | 97 | 97 | 68 | |||
70.0 | 37/16 | 37/1.62 | 122 | 109 | 109 | 70 | |||
127 | 117 | 112 | 79 | 37/2.06 | 120 | ||||
95.0 | 37/15 | 37/1.82 | 141 | 128 | 124 | 87 | |||
145 | 128 | 125 | 88 | 37/2.24 | 150 | ||||
170 | 149 | 144 | 101 | 37/2.50 | 185 | ||||
120.0 | 37/14 | 37/2.10 | 173 | 152 | 150 | 106 | |||
200 | 171 | 165 | 117 | 37/2.80 | 225 | ||||
150.0 | 37/13 | 37/2.36 | 202 | 179 | 174 | 123 | |||
185.0 | 37/12 | 37/2.62 | 231 | 204 | 196 | 137 | |||
244 | 208 | 200 | 139 | 61/2.50 | 300 | ||||
250.0 | 61/13 | 61/2.36 | 293 | 248 | 235 | 165 | |||
300 | 257 | 275 | 61/3.00 | 400 | |||||
300.0 | 61/12 | 61/2.62 | 330 | 283 |
Nominal Conductor Area | Continuous Current Rating | Short Circuit Rating (1 s) | DC resistance at 20 °C | Capacitance per km (at 50 Hz) | Inductive reactance per km (at 50 Hz) | 3.5 Core | 4 Core | ||||
---|---|---|---|---|---|---|---|---|---|---|---|
Ground | Duct | Air | Overall Diameter | Mass | Over all Diameter | Mass | |||||
mm² | A | A | A | kA | Ω | μF | Ω | mm | kg/km | mm | kg/km |
10 | 46 | 39 | 40 | 0.748 | 3.000 | 0.577 | 0.0888 | - | - | 22.0 | 785 |
16 | 60 | 50 | 51 | 1.200 | 1.910 | 0.757 | 0.0857 | - | - | 25.5 | 1050 |
25 | 76 | 63 | 70 | 2.080 | 1.200 | 1.860 | 0.0849 | 26.0 | 1162 | 27.0 | 1285 |
35 | 92 | 77 | 86 | 2.600 | 0.868 | 0.981 | 0.0823 | 28.5 | 1340 | 29.0 | 1425 |
50 | 110 | 95 | 105 | 3.660 | 0.641 | 0.997 | 0.0795 | 32.0 | 1702 | 33.5 | 1815 |
70 | 135 | 115 | 130 | 5.660 | 0.443 | 1.163 | 0.0769 | 36.0 | 2097 | 37.0 | 2455 |
95 | 160 | 140 | 155 | 7.050 | 0.320 | 1.181 | 0.0766 | 40.0 | 2635 | 42.5 | 2910 |
120 | 185 | 155 | 180 | 9.350 | 0.253 | 1.310 | 0.0741 | 44.0 | 3139 | 46.0 | 3465 |
150 | 200 | 175 | 205 | 11.070 | 0.206 | 1.282 | 0.0743 | 48.5 | 3667 | 50.5 | 3985 |
185 | 235 | 200 | 240 | 13.740 | 0.164 | 1.300 | 0.0742 | 53.5 | 4477 | 55.5 | 4915 |
225 | 264 | 225 | 269 | 17.270 | 0.134 | 1.304 | 0.0741 | 59.0 | 5347 | 61.5 | 5875 |
240 | 275 | 235 | 280 | 19.850 | 0.125 | 1.342 | 0.0737 | 60.5 | 5547 | 62.5 | 6475 |
300 | 305 | 260 | 315 | 22.630 | 0.100 | 1.365 | 0.0733 | 66.5 | 6673 | 69.0 | 7255 |
400 | 335 | 290 | 375 | 32.700 | 0.078 | 1.426 | 0.0729 | 73.5 | 8164 | 77.0 | 9590 |
500 | 370 | 320 | 425 | 38.350 | 0.062 | 1.406 | 0.0732 | 82.5 | 10083 | 87.5 | 10085 |
630 | 405 | 350 | 480 | 48.350 | 0.048 | 1.424 | 0.0731 | 94.0 | - | 97.5 | 13680 |
No. of cores and Conductor Area | Continuous Current Rating | DC resistance at 20 °C | Unarmored Cable | Armored Cable | |||
---|---|---|---|---|---|---|---|
Ground | Air / Duct | Overall Diameter | Mass | Overall Diameter | Mass | ||
mm² | A | A | Ω/km | mm | kg/km | mm | kg/km |
2 x 1.5 | 23 | 20 | 12.10 | 10.6 | 155 | 14.0 | 418 |
3 x 1.5 | 21 | 17 | 12.10 | 11.0 | 180 | 14.5 | 452 |
4 x 1.5 | 21 | 17 | 12.10 | 12.0 | 210 | 15.6 | 496 |
5 x 1.5 | 16 | 14 | 12.10 | 12.6 | 250 | 16.5 | 566 |
6 x 1.5 | 15 | 13 | 12.10 | 14.0 | 280 | 17.0 | 627 |
7 x 1.5 | 14 | 13 | 12.10 | 14.0 | 310 | 17.2 | 637 |
10 x 1.5 | 13 | 11 | 12.10 | 17.0 | 423 | 19.8 | 695 |
12 x 1.5 | 12 | 10 | 12.10 | 17.6 | 470 | 20.4 | 723 |
16 x 1.5 | 11 | 9 | 12.10 | 19.7 | 560 | 21.8 | 885 |
24 x 1.5 | 9 | 8 | 12.10 | 24.3 | 752 | 25.9 | 1115 |
61 x 1.5 | 6 | 6 | 12.10 | 34.1 | 1705 | 36.4 | 2310 |
2 x 2.5 | 32 | 27 | 7.28 | 13.1 | 218 | 15.4 | 490 |
4 x 2.5 | 27 | 24 | 7.28 | 14.5 | 290 | 16.8 | 610 |
6 x 2.5 | 21 | 18 | 7.28 | 16.6 | 390 | 20.4 | 770 |
10 x 2.5 | 18 | 15 | 7.28 | 21.2 | 560 | 22.0 | 840 |
12 x 2.5 | 17 | 14 | 7.28 | 21.5 | 640 | 22.4 | 960 |
16 x 2.5 | 15 | 13 | 7.28 | 23.1 | 790 | 24.8 | 1160 |
24 x 2.5 | 13 | 11 | 7.28 | 27.7 | 1105 | 29.8 | 1510 |
61 x 2.5 | 9 | 8 | 7.28 | 40.4 | 2490 | 42.0 | 3200 |
Current in A | Cable cross section (mm²) | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
2.5 | 4 | 6 | 10 | 16 | 25 | 35 | 50 | 70 | 95 | 120 | 150 | 185 | 240 | 300 | 400 | |
4 | 215 | 383 | 513 | |||||||||||||
5 | 170 | 263 | 405 | 707 | ||||||||||||
9 | 98 | 153 | 235 | 411 | ||||||||||||
16 | 83 | 128 | 223 | 329 | 572 | |||||||||||
23 | 88 | 153 | 226 | 393 | ||||||||||||
29 | 122 | 179 | 311 | 388 | ||||||||||||
40 | 130 | 226 | 281 | 393 | 605 | |||||||||||
53 | 170 | 212 | 297 | 456 | 563 | |||||||||||
66 | 170 | 238 | 366 | 453 | 603 | |||||||||||
80 | 196 | 302 | 374 | 497 | 567 | |||||||||||
95 | 165 | 254 | 315 | 419 | 477 | 575 | ||||||||||
130 | 186 | 230 | 306 | 349 | 420 | 565 | ||||||||||
190 | 238 | 287 | 386 | 417 | 512 | |||||||||||
270 | 272 | 293 | 360 |
Nominal Conductor Area | Unarmored 3 Single Core | 3 Core Unarmored and Served | 3 Core Armored and Served | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Servings Touching | Belted Cable | Screened Cable | Belted Cable | Screened Cable | |||||||||||
Gnd | Duct | Air | Gnd | Duct | Air | Gnd | Duct | Air | Gnd | Duct | Air | Gnd | Duct | Air | |
mm² | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A |
16 | 63 | 62 | 66 | 55 | 50 | 50 | 60 | 51 | 59 | 58 | 49 | 50 | 61 | 54 | 59 |
25 | 78 | 82 | 88 | 72 | 64 | 65 | 73 | 66 | 77 | 72 | 64 | 68 | 80 | 65 | 77 |
35 | 93 | 96 | 105 | 84 | 77 | 79 | 92 | 77 | 93 | 84 | 74 | 80 | 95 | 80 | 93 |
50 | 115 | 115 | 130 | 105 | 94 | 100 | 115 | 94 | 115 | 105 | 92 | 100 | 115 | 100 | 115 |
70 | 140 | 140 | 165 | 130 | 115 | 125 | 140 | 115 | 140 | 130 | 115 | 125 | 140 | 125 | 140 |
95 | 165 | 165 | 200 | 155 | 135 | 155 | 165 | 135 | 175 | 155 | 135 | 155 | 165 | 145 | 175 |
120 | 185 | 185 | 230 | 170 | 150 | 175 | 185 | 155 | 200 | 170 | 155 | 175 | 185 | 160 | 200 |
150 | 210 | 205 | 265 | 190 | 170 | 200 | 210 | 175 | 230 | 190 | 175 | 200 | 205 | 180 | 230 |
185 | 240 | 230 | 300 | 220 | 195 | 230 | 245 | 200 | 265 | 220 | 200 | 230 | 235 | 210 | 265 |
225 | 260 | 250 | 340 | 240 | 210 | 260 | 270 | 225 | 280 | 240 | 220 | 260 | 265 | 230 | 300 |
240 | 270 | 260 | 355 | 260 | 235 | 275 | 285 | 235 | 315 | 250 | 225 | 265 | 275 | 240 | 310 |
300 | 305 | 285 | 400 | 300 | 265 | 315 | 310 | 265 | 355 | 280 | 250 | 310 | 300 | 265 | 315 |
400 | 355 | 335 | 490 | 345 | 300 | 375 | 360 | 320 | 405 | 320 | 285 | 365 | 357 | 315 | 408 |
500 | 395 | 365 | 570 | 385 | 330 | 425 | 405 | 350 | 460 | 360 | 310 | 415 | 385 | 330 | 450 |
625 | 445 | 410 | 670 | 410 | 365 | 480 | 435 | 390 | 520 | 385 | 345 | 470 | 410 | 370 | 510 |
800 | 495 | 455 | 750 | ||||||||||||
1000 | 550 | 495 | 820 |
Nominal Conductor Area | Continuous Current Rating | Short Circuit Rating (1 s) | DC resistance at 20 °C | Capacitance (at 50 Hz) | Inductive reactance (at 50 Hz) | Overall Diameter | Mass | ||
---|---|---|---|---|---|---|---|---|---|
Ground | Duct | Air | |||||||
mm² | A | A | A | kA | Ω/km | μF/km | Ω/km | mm | kg/km |
50 | 115 | 100 | 115 | 3.62 | 0.641 | 0.370 | 0.0973 | 49.0 | 5855 |
70 | 140 | 125 | 140 | 5.63 | 0.443 | 0.440 | 0.0918 | 53.5 | 6855 |
95 | 165 | 145 | 175 | 7.00 | 0.320 | 0.480 | 0.0893 | 57.5 | 7495 |
120 | 185 | 160 | 200 | 9.29 | 0.253 | 0.538 | 0.0853 | 60.0 | 8180 |
150 | 205 | 180 | 230 | 10.98 | 0.206 | 0.580 | 0.0837 | 64.5 | 9390 |
185 | 235 | 210 | 265 | 13.64 | 0.164 | 0.635 | 0.0817 | 68.0 | 10200 |
225 | 265 | 230 | 300 | 17.14 | 0.134 | 0.702 | 0.0798 | 72.0 | 11565 |
240 | 275 | 240 | 310 | 19.70 | 0.125 | 0.745 | 0.0787 | 73.5 | 12080 |
300 | 300 | 265 | 315 | 22.47 | 0.100 | 0.789 | 0.0776 | 73.5 | 13900 |
400 | 357 | 315 | 408 | 32.45 | 0.078 | 0.931 | 0.0751 | 85.5 | 16880 |
Nominal Cross-sectional Area | No. and dia. of wires | 650 V / 1.1 kV Grade | ||
---|---|---|---|---|
Twin Core | Three Core | Four Core | ||
mm² | mm | A | A | A |
0.5 | 16 / 0.200 | 11 | 9 | 9 |
0.75 | 24 / 0.200 | 14 | 12 | 11 |
1.00 | 32 / 0.200 | 15 | 13 | 12 |
1.50 | 48 / 0.200 | 21 | 18 | 16 |
2.50 | 80 / 0.200 | 28 | 24 | 22 |
4.00 | 128 / 0.200 | 37 | 32 | 29 |
Nominal Cross-sectional Area | No. and Dia of wires | 650 V / 1.1 kV Grade | |||
---|---|---|---|---|---|
Single Core | Twin Core | Three Core | Four Core | ||
mm² | mm | A | A | A | A |
6 | 85 / 0.300 | 55 | 45 | 38 | 36 |
10 | 62 / 0.450 | 75 | 60 | 52 | 47 |
16 | 101 / 0.450 | 100 | 80 | 70 | 64 |
25 | 157 / 0.450 | 130 | 105 | 92 | 83 |
35 | 220 / 0.450 | 160 | 130 | 120 | 100 |
50 | 314 / 0.450 | 205 | 160 | 140 | 125 |
70 | 158 / 0.750 | 250 | 200 | 175 | 155 |
95 | 215 / 0.750 | 300 | 240 | 205 | 190 |
120 | 272 / 0.750 | 345 | 270 | 240 | 220 |
150 | 340 / 0.750 | 415 | 320 | 285 | 260 |
185 | 419 / 0.750 | 465 | 360 | 315 | 295 |
240 | 543 / 0.750 | 540 | 420 | 365 | 340 |
300 | 679 / 0.750 | 640 | 495 | 435 | 400 |
400 | 905 / 0.750 | 770 |
Cable Size (mm) | Current Rating (A) | Cable Size (mm) | Current Rating (A) |
---|---|---|---|
9/0.300 | 5 | 28/0.300 | 15 |
14/0.300 | 9 | 35/0.300 | 18 |
16/0.300 | 10 | 44/0.300 | 20 |
19/0.300 | 11 | 65/0.300 | 25 |
Nominal Cross-sectional Area | No. and dia. of wires | Current Rating |
---|---|---|
mm² | mm | A |
16 | 509 / 0.200 | 100 |
25 | 796 / 0.200 | 150 |
35 | 1114 / 0.200 | 230 |
50 | 1591 / 0.200 | 400 |
70 | 2228 / 0.200 | 600 |
95 | 1344 / 0.300 | Used when voltage drop with smaller cable becomes excessive. |
Cable Size in mm² | 50 mm × 50 mm | 75 mm × 75 mm | 100 mm × 100 mm |
---|---|---|---|
1.0 | 65 | 140 | 200 |
1.5 | 45 | 100 | 180 |
2.5 | 40 | 90 | 160 |
4.0 | 35 | 80 | 140 |
6.0 | 29 | 65 | 116 |
10.0 | 24 | 54 | 96 |
16.0 | 14 | 35 | 56 |
25.0 | 12 | 27 | 48 |
35.0 | 10 | 21 | 40 |
50.0 | 8 | 18 | 32 |
70.0 | 5 | 10 | 20 |
95.0 | 4 | 9 | 16 |
120.0 | 3 | 5 | 12 |
150.0 | 4 | 7 |
Note
Number of cables is based on a space factor of 45 %. Suitable allowance should be made for voltage drop and temperature rise of bunched cables.
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