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Currrent Rating

Current Rating



The current ratings given are based on normal condition of installation described below:

Cables shall only be operated at their full rating if the minimum current at which circuit protection is designed to operate does not exceed 1.5 times (in the case of cables in air or in ducts) or 1.3 times (in the case of cables laid direct in the ground).

01 Maximum Conductor Temperature 700 for GP PVC Insulation & 850 C for HR Insulation
02 Thermal Resistivity of soil 1500 C cm/w
03 Thermal Resistivity of PVC 6500 C cm/w
04 Ground Temperature 300 C
05 Ambient air Temperature 400 C
06 Depth of Laying (for cable laid direct in the ground) 75 cms
Short Circuit Rating in K. amp for One Second duration
  Area of Conductor Aluminum Conductor Copper Conductor
  Sq. mm GPPVC HRPVC GPPVC HRPVC
  1.5 0.1126 0.097 0.169 0.153
  2.5 0.1878 0.162 0.283 0.255
  4 0.3004 0.259 0.452 0.406
  6 0.4507 0.389 0.67 0.612
  10 0.7512 0.648 1.132 1.020
  16 1.200 1.087 1.810 1.632
  25 1.870 1.620 2.830 2.550
  35 2.620 2.270 3.960 3.570
  50 3.750 3.243 5.660 5.100
  70 5.250 4.540 7.920 7.140
  95 7.13 6.150 10.750 9.690
  120 9.00 7.784 13.580 13.340
  150 11.260 9.730 16.980 15.300
  185 13.890 12.000 20.940 18.870
  240 18.020 15.560 17.160 24.480
  300 22.530 19.460 33.960 30.600
  400 30.040 25.940 45.280 40.800
  500 37.560 32.43 56.600 51.000
  630 47.320 40.860 71.310 64.250

Note : For cables in air, no reduction in current rating is necessary provided that
> The horizontal clearance between circuits is:
    (a) not less than six times the overall diameter of an individual cable, and
    (b) not less than the overall width of an individual circuit, except that the horizontal clearance need not in any case exceed 150 mm
> The vertical clearance between circuits is not less than 150mm
> If the number of circuits exceeds, they are installed in a horizontal plane.
However for installations conditions other than above current rating factors incorporated in IS 3961 Part-Il may please be applied.

The following points should be taken into consideration before selecting any particular size & type of cable:
Bending Radius
Recommended Pulling Force