Fire Resisting Cable

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Fire Resisting Cables

Current Rating and Voltage Drop

Single Core Cables having PVC Insulation, Unarmoured, With or Without Sheath (Copper Conductor)

450/750V or 600/1000V Current-Carrying Capacities (Amp) PVC & PVC/PVC Cables

  Reference Method 4 (Enclosed in conduit in thermally insulating wall etc) Reference Method 3 (Enclosed in conduit on a wall or in trunking etc) Reference Method 1 (Clipped direct) Reference Method 11 (on a perforated cable tray horizontal or vertical) Reference Method 12 (free air)
Horizontal flat spaced Vertical flat spaced Trefoil
Conductor cross-sectional area (mm²) 2 cables single-phase ac or dc (Amp) 3 or 4 cables 3-phase ac (Amp) 2 cables single-phase ac or dc (Amp) 3 or 4 cables 3-phase ac (Amp) 2 cables single-phase ac or dc (Amp) 3 or 4 cables 3-phase ac (Amp) 2 cables single-phase ac or dc or flat and touching (Amp) 3 cables 3-phase ac flat and touching (Amp) 2 cables single-phase ac or dc or 3 cables or trefoil (Amp) 2 cables single-phase ac or dc or 3 cables 3-phase ac (Amp) 3 cables trefoil 3-phase ac (Amp)
BS 6004 1 11 10.5 13.5 12 15.5 14 - - - - -
1.5 14.5 13.5 17.5 15.5 20 18 - - - - -
2.5 19.5 18 24 21 27 25 - - - - -
4 26 24 32 28 37 33 - - - - -
6 34 31 41 36 47 43 - - - - -
10 46 42 57 50 65 59 - - - - -
16 61 56 76 68 87 79 - - - - -
25 80 73 101 89 114 104 126 112 146 130 110
35 99 89 125 110 141 129 156 141 181 162 137
BS 6346 50 119 108 151 134 182 167 191 172 219 197 167
70 151 136 192 171 234 214 246 223 281 254 216
95 182 164 232 207 284 261 300 273 341 311 264
120 210 188 269 239 330 303 349 318 396 362 308
150 240 216 300 262 381 349 404 369 456 419 356
185 273 245 341 296 436 400 463 424 521 480 409
240 320 286 400 346 515 472 549 504 615 569 485
300 367 328 458 394 594 545 635 584 709 659 561
400 - - 546 467 694 634 732 679 852 795 656
500 - - 626 533 792 723 835 778 982 920 749
630 - - 720 611 904 826 953 892 1138 1070 855
800 - - - - 1030 943 1086 1020 1265 1188 971
1000 - - - - 1154 1058 1216 1149 1420 1337 1079

*With or without protective conductor

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

Group Rating Factor please refer to Table G Voltage Drop (Per Amp Per Meter) PVC & PVC/PVC Cables

Conductor cross-sectional area (mm²) 2 cables dc (mV/A/m) 2 cables-single-phase ac 3 or 4 cables-three-phase ac
Reference Methods 3 &4 (Enclosed in conduit etc in or on a wall) (mV/A/m) Reference Methods 1 & 11 (Clipped direct or on trays, touching) (mV/A/m) Reference Methods 12 (space*) (mV/A/m) Reference Methods 3 &4 (Enclosed in conduit etc in or on a wall) (mV/A/m) Reference Methods 1, 11 & 12 (in trefoil) (mV/A/m) Reference Methods 1 & 11 (Flat touching) (mV/A/m) Reference Methods 12 (Flat spaced*) (mV/A/m)
1 44 44 44 44 38 38 38 38
1.5 29 29 29 29 25 25 25 25
2.5 18 18 18 18 15 15 15 15
4 11 11 11 11 9.5 9.5 9.5 9.5
6 7.3 7.3 7.3 7.3 6.4 6.4 6.4 6.4
10 4.4 4.4 4.4 4.4 3.8 3.8 3.8 3.8
16 2.8 2.8 2.8 2.8 2.4 2.4 2.4 2.4
    r x z r x z r x z r x Z r x z r x z r x z
25 1.75 1.80 0.33 1.8 1.75 0.20 1.75 1.75 0.29 1.80 1.50 0.29 1.55 1.50 0.175 1.50 1.50 0.25 1.55 1.50 0.32 1.55
35 1.25 1.30 0.31 1.3 1.25 0.195 1.25 1.25 0.28 1.30 1.10 0.27 1.10 1.10 0.170 1.10 1.10 0.24 1.10 1.10 0.32 1.15
50 0.93 0.95 0.30 1.00 0.93 0.190 0.95 0.93 0.28 0.97 0.81 0.26 0.85 0.80 0.165 0.82 0.80 0.24 0.84 0.80 0.32 0.86
70 0.63 0.65 0.29 0.72 0.63 0.185 0.66 0.63 0.27 0.69 0.56 0.25 0.61 0.55 0.160 0.57 0.55 0.24 0.60 0.55 0.31 0.63
95 0.46 0.49 0.28 0.56 0.47 0.180 0.50 0.47 0.27 0.54 0.42 0.24 0.48 0.41 0.155 0.43 0.41 0.23 0.47 0.40 0.31 0.51
120 0.36 0.39 0.27 0.47 0.37 0.175 0.41 0.37 0.26 0.45 0.33 0.23 0.41 0.32 0.150 0.36 0.32 0.23 0.40 0.32 0.30 0.44
150 0.29 0.31 0.27 0.41 0.30 0.175 0.34 0.29 0.26 0.39 0.27 0.23 0.36 0.26 0.150 0.30 0.26 0.23 0.34 0.26 0.30 0.40
185 0.23 0.25 0.27 0.37 0.24 0.170 0.29 0.24 0.26 0.35 0.22 0.23 0.32 0.21 0.145 0.26 0.21 0.22 0.31 0.21 0.30 0.36
240 0.180 0.195 0.26 0.33 0.185 0.165 0.25 0.185 0.25 0.31 0.17 0.23 0.29 0.160 0.145 0.22 0.160 0.22 0.27 0.160 0.29 0.34
300 0.145 0.160 0.26 0.31 0.150 0.165 0.22 0.150 0.25 0.29 0.14 0.23 0.27 0.130 0.140 0.190 0.130 0.22 0.25 0.130 0.29 0.32
400 0.105 0.130 0.26 0.29 0.120 0.160 0.20 0.115 0.25 0.27 0.12 0.22 0.25 0.105 0.140 0.175 0.105 0.21 0.24 0.100 0.29 0.31
500 0.086 0.110 0.26 0.28 0.098 0.155 0.185 0.093 0.24 0.26 0.10 0.22 0.25 0.086 0.135 0.160 0.086 0.21 0.23 0.081 0.29 0.30
630 0.068 0.094 0.25 0.27 0.081 0.155 0.175 0.076 0.24 0.25 0.08 0.22 0.24 0.072 0.135 0.150 0.072 0.21 0.22 0.066 0.28 0.29
800 0.053 - - - 0.068 0.150 0.165 0.061 0.24 0.25 - - - 0.060 0.130 0.145 0.060 0.21 0.22 0.053 0.28 0.29
1000 0.042 - - - 0.059 0.150 0.160 0.050 0.24 0.24 - - - 0.052 0.130 0.140 0.052 0.20 0.21 0.044 0.28 0.28

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: