Fire Resisting Cable

Fire Resisting Cables

Current Rating and Voltage Drop

Multi-Core Cables having PVC Insulation, Unarmoured (Copper Conductor) 600/1000V

Current-Carrying Capacities (Amp) PVC/PVC Cables
Conductor cross-sectional area (mm²) Reference Method 4 (Enclosed in an insulated wall etc) Reference Method 3 (Enclosed in conduit on a wall or cell, or in trunking) Reference Method 1 (Clipped direct) Reference Method 11 (on perforated cable tray) or Reference Method 13 (free air)
1 2-core cable* single-phase ac or dc (Amp) 1 3-core cable* or 1 4-core cable 3-phase ac (Amp) 1 2-core cable* single-phase ac or dc (Amp) 1 3-core cable* or 1 4-core cable 3-phase ac (Amp) 1 2-core cable* single-phase ac or dc (Amp) 1 3-core cable* or 1 4-core cable 3-phase ac (Amp) 1 2-core cable* single-phase ac or dc (Amp) 1 3-core cable* or 1 4-core cable 3-phase ac (Amp)
1 11 10 13 11.5 15 13.5 17 14.5
1.5 14 13 16.5 15 19.5 17.5 22 18.5
2.5 18.5 17.5 23 20 27 24 30 25
4 25 23 30 27 36 32 40 34
6 32 29 38 34 46 41 51 43
10 43 39 52 46 63 57 70 60
16 57 52 69 62 85 76 94 80
25 75 68 90 80 112 96 119 101
35 92 83 111 99 138 119 148 126
50 110 99 133 118 168 144 180 153
70 139 125 168 149 213 184 232 196
95 167 150 201 179 258 223 282 238
120 192 172 232 206 299 259 328 276
150 219 196 258 225 344 299 379 319
185 248 223 294 255 392 341 434 364
240 291 261 344 297 461 403 514 430
300 334 298 394 339 530 464 593 497
400 - - 470 402 634 557 715 597

*With or without protective conductor

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

Group Rating Factor please refer to Table G

Voltage Drop (Per Amp Per Meter) PVC/PVC Cables
Conductor cross-sectional area (mm²) 2-core cable dc (mV/A/m) 2-core cable single-phase ac (mV/A/m) 3 or 4-core cable 3-phase ac (mV/A/m)
1 44 44 38
1.5 29 29 25
2.5 18 18 15
4 11 11 9.5
6 7.3 7.3 6.4
10 4.4 4.4 3.8
16 2.8 2.8 2.4
    r x z r x Z
25 1.75 1.75 0.170 1.75 1.50 0.145 1.50
35 1.25 1.25 0.165 1.25 1.10 0.145 1.10
50 0.93 0.93 0.165 0.94 0.80 0.140 0.81
70 0.63 0.63 0.160 0.65 0.55 0.140 0.57
95 0.46 0.47 0.155 0.50 0.41 0.135 0.43
120 0.36 0.38 0.155 0.41 0.33 0.135 0.35
150 0.29 0.30 0.155 0.34 0.26 0.130 0.29
185 0.23 0.25 0.150 0.29 0.21 0.130 0.25
240 0.180 0.190 0.150 0.24 0.165 0.130 0.21
300 0.145 0.155 0.145 0.21 0.135 0.130 0.185
400 0.105 0.115 0.145 0.185 0.100 0.125 0.160

Note: r=conductor resistance at operating temperature

Z=impedance, x=reactance

Table A: Rating Factors for Other Ambient Air Temperatures (PVC Insulated)

Ambient Temperature 25℃ 30℃ 35℃ 40℃ 45℃ 50℃ 55℃ 60℃ 65℃ 70℃
Rating Factor 1.03 1.00 0.94 0.87 0.79 0.71 0.61 0.50 0.35 -
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: