Fire Resisting Cable

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Fire Resisting Cables

Current Rating and Voltage Drop

Multi-Core Cables having XLPE Insulation, Armoured (Copper Conductor) 600/1000V

Current-Carrying Capacities (Amp) XLPE /SWA/PVC Cables
Size of Conductor Reference Method 1 (Clipped direct) Reference Method 11 (on perforated cable tray) or Reference Method 13 (free air) In Single Way Ducts Laid Direct in Ground
1 2-core cable 1-phase ac or dc 1 3- or 4-core cable 3-phase ac 1 2-core cable 1-phase ac or dc 1 3- or 4-core cable 3-phase ac 1 2-core cable 1-phase ac or dc 1 3- or 4-core cable 3-phase ac 1 2-core cable 1-phase ac or dc 1 3- or 4-core cable 3-phase ac
1 mm² 2 A 3 A 4 A 5 A 6 A 7 A 8 A 9 A
1.5 27 23 29 25 - 23 - 28
2.5 36 31 39 33 - 30 - 36
4 49 42 52 44 - 40 - 48
6 62 53 66 56 - 50 - 60
10 85 73 90 78 - 65 - 80
16 110 94 115 99 115 94 140 115
25 146 124 152 131 145 125 180 150
35 180 154 188 162 175 150 215 180
50 219 187 228 197 210 175 255 215
70 279 238 291 251 260 215 315 265
95 338 289 354 304 310 260 380 315
120 392 335 410 353 355 300 430 360
150 451 386 472 406 400 335 480 405
185 515 441 539 463 455 380 540 460
240 607 520 636 546 520 440 630 530
300 698 599 732 628 590 495 700 590
400 787 673 847 728 660 560 790 670

Note: Rating factors for ambient temperature other than 30℃ please refer Table C

Rating factors for ground temperature other than 15℃ please refer Table D

Group Rating Factor please refer to Table F & Table G

Voltage Drop (Per Amp Per Meter) XLPE/SWA/PVC Cables
Size of Conductor 2-core cable dc 2-core cables 1-phase ac 3- & 4-core cables 3-phase ac 2-core cables 1-phase ac 3- or 4-core cables 3-phase ac
In ducts In ground In ducts In ground
1 mm² 2 mV/A/m 3 mV/A/m 4 mV/A/m 5 mV/A/m 6 mV/A/m 7 mV/A/m 8 mV/A/m
1.5 31 31 27 31 31 25 25
2.5 19 19 16 19 19 15 15
4 12 12 10 12 12 9.7 9.7
6 7.9 7.9 6.8 7.9 7.9 6.5 6.5
10 4.7 4.7 4.0 4.7 4.7 3.9 3.9
16 2.9 2.9 2.5 2.9 2.9 2.6 2.6
    r x z r x z        
25 1.85 1.85 0.16 1.9 1.6 0.14 1.65 1.9 1.9 1.6 1.6
35 1.35 1.35 0.155 1.35 1.15 0.135 1.15 1.35 1.35 1.2 1.2
50 0.98 0.99 0.155 1.00 0.86 0.135 0.87 1.00 1.00 0.87 0.87
70 0.67 0.67 0.150 0.69 0.59 0.130 0.60 0.69 0.69 0.61 0.61
95 0.49 0.50 0.150 0.52 0.43 0.130 0.45 0.52 0.52 0.45 0.45
120 0.39 0.40 0.145 0.42 0.34 0.130 0.37 0.42 0.42 0.36 0.36
150 0.31 0.32 0.145 0.35 0.28 0.125 0.30 0.35 0.35 0.30 0.30
185 0.25 0.26 0.145 0.29 0.22 0.125 0.26 0.29 0.29 0.25 0.25
240 0.195 0.20 0.140 0.24 0.175 0.125 0.21 0.24 0.24 0.21 0.21
300 0.155 0.16 0.140 0.21 0.140 0.120 0.185 0.21 0.21 0.19 0.19
400 0.120 0.13 0.140 0.19 0.115 0.120 0.165 0.19 0.19 0.18 0.18

Note: r=conductor resistance at operating temperature

Z=impedance, x=reactance

Table C: Rating Factors for Other Ambient Air Temperatures (XLPE Insulated)

Ambient Temperature 25℃ 30℃ 35℃ 40℃ 45℃ 50℃ 55℃ 60℃ 65℃ 70℃ 75℃ 80℃ 85℃
Rating Factor 1.02 1.00 0.96 0.91 0.87 0.82 0.76 0.71 0.65 0.58 0.50 0.41 0.29

Table D: Rating Factors for Other Ground Temperatures (XLPE Insulated)

Ground Temperature 15℃ 20℃ 25℃ 30℃ 35℃ 40℃ 45℃ 50℃
Rating Factor 1.00 0.97 0.93 0.89 0.86 0.82 0.77 0.73

Table F: Group Rating Factors for Cables Installation

Group Rating Factors Number of Circuits
2 3 4 5 6 7 8 9 10 11 12
1 For circuits of 2 Single core cables laid flat touching horizontal formation, laid direct in ground 0.79 0.68 0.62 0.57 0.54 0.52 0.50 0.48 0.47 0.46 0.45
2 For circuits of 3 Single core cables in trefoil touching, laid direct in ground 0.78 0.66 0.61 0.56 0.53 0.50 0.49 0.47 0.46 0.44 0.43
  Number of Cables in a Group
2 3 4 5 6 7 8 9 10 11 12
3 For twin or multi-cores cables in horizontal formation, laid direct in ground Spaced 0.15m 0.87 0.78 0.74 0.70 0.68 0.66 0.64 0.63 0.62 0.61 0.60
Spaced 0.30m 0.91 0.84 0.81 0.78 0.77 0.75 0.75 0.74 0.73 0.73 0.72
      Number of Ducts in a Group
      2 3 4 5 6 7 8 9 10 11 12
4 For twin or multi-cores cables in single-way ducts horizontal formation spaced 0.30m apart 0.93 0.88 0.85 0.83 0.82 0.81 0.80 0.79 0.79 0.78 0.78
Table G Correction Factors for Groups of More than One Circuit of Single Core Cables, or More than One Multi-Cores Cable
Reference Methods of Installation Correction Factor (Cg)
  Number of Circuits or Multi-cores Cables
  2 3 4 5 6 7 8 9 10 12 14 16 18 20
Enclosed (Method 3 or 4) or bunched and clipped direct to a non-metallic surface (Method 1) 0.80 0.70 0.65 0.60 0.57 0.54 0.52 0.50 0.48 0.45 0.43 0.41 0.39 0.38
Single layer clipped to a non-metallic surface (Method 1) Touching 0.85 0.79 0.75 0.73 0.72 0.72 0.71 0.70 - - - - - -
Spaced* 0.94 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
Single layer multi-cores on a perforated metal cable tray, vertical or horizontal(Method 11) Touching 0.86 0.81 0.77 0.75 0.74 0.73 0.73 0.72 0.71 0.70 - - - -
Spaced* 0.91 0.89 0.88 0.87 0.87 - - - - - - - - -
Single layer single core on a perforated metal cable tray, touching (Method 11) Horizontal 0.90 0.85 - - - - - - - - - - - -
Vertical 0.85 - - - - - - - - - - - - -
Single layer multi-cores touching on ladder supports (Method 13) 0.86 0.82 0.80 0.79 0.78 0.78 0.78 0.77 - - - - - -

*Space means a clearance between adjacent surfaces of at least one cable diameter (De). Where the horizontal clearance between adjacent cables exceeds 2 De, no correction factor need be applied.

Note: