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Current Carrying Capacity of Cables

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Current Carrying Capacity (Amps) of Cables (Copper Conductors)

Table 4D1A – Single core 700c thermoplastic insulated cables (e.g. PVC Singles), non-armoured with or without sheath.  All values assume an ambient temperature of 300c and a conductor operating temperature of 700c. 

Conductor CSA Reference Method A (enclosed in conduit in thermally insulating wall etc)  Reference Method B (enclosed in conduit on a wall or in trunking etc)  Reference Method C (clipped direct)  Reference method F (in free air or on a perforated cable tray horizontal or vertical)
 
Touching Spaced by one diameter
 
2 cables, 1ph ac or dc flat 3 cables, 3ph ac flat
 
2 cables, 1ph ac or dc 3 or 4 cables, 3ph ac 2 cables, 1ph ac or dc 3 or 4 cables, 3ph ac 2 cables, 1ph ac or dc 3 or 4 cables, 3ph ac 2 cables, 1ph ac or dc flat 3 cables 3ph ac flat
 
3 cables, 3ph ac
 trefoil
Horizontal Vertical
 1mm2  11  10.5  13.5 12  15.5 14          
1.5mm2  14.5  13.5  17.5 15.5  20 18          
2.5mm2  20  18  24 21  27 25          
4mm2  26  24  32 28  37 33          
6mm2  34  31  41 36  47 43          
10mm2  46  42  57 50  65 59          
16mm2  61  56  76 68  87 79          
25mm2 80 73 101 89 114 104  131 114 110 146 130
35mm2  99  89  125 110  141 129  162 143 137 181 162

 

 

For sizes greater than 35mm2, see table 4D1A

Table 4D2A – Multicore 700c thermoplastic insulated & thermoplastic sheathed cables (e.g. PVC T&E), non-armoured.  All values assume an ambient temperature of 300c and a conductor operating temperature of 700c.

 

Conductor CSA  Reference Method A (enclosed in conduit in thermally insulating wall etc) Reference Method B (enclosed in conduit on a wall or in trunking etc) Reference Method C (clipped direct) Reference Method E (in free air or on a perforated cable tray, horizontal or vertical)
1 two core cable*, 1ph ac or dc  1 three core cable* or 1 four core cable, 3ph ac  1 two core cable*, 1ph ac or dc  1 three core cable* or 1 four core cable, 3ph ac  1 two core cable*, 1ph ac or dc  1 three core cable* or 1 four core cable, 3ph ac  1 two core cable*, 1ph ac or dc  1 three core cable* or 1 four core cable, 3ph ac
 
1mm2  11  10  13 11.5  15 13.5  17 14.5
1.5mm2  14  13  16.5 15  19.5 17.5  22 18.5
2.5mm2  18.5  17.5  23 20  27 24  30 25
4mm2  25  23  30 27  36 32  40 34
6mm2  32  29  38 34 46  41  51 43
10mm2  43  39  52 46  63 57  70 60
 16mm2  57  52  69 62  85 76 94  80




 
*with or without a protective conductor

For sizes greater than 16mm2, see table 4D2A.  For current capacity values of SWA single cables (50mm2 – 100mm2), table 4D3A is used.


Table 4D4A – Multicore 700c armoured thermoplastic insulated cables (e.g. SWA cable).  All values assume that air ambient temperature of 300c, ground ambient temperature of 200c & conductor operating temperature of 700c.
 

Conductor CSA Reference Method C (clipped direct) Reference Method E (in free air or on a perforated cable tray, horizontal or vertical) Reference Method D (direct in ground or in ducting in ground, in or around buildings)
1 two core cable, 1ph ac or dc 1 three core cable or 1 four core cable, 3ph ac 1 two core cable, 1ph ac or dc 1 three core cable or 1 four core cable, 3ph ac 1 two core cable, 1ph ac or dc 1 three core cable or 1 four core cable, 3ph ac
 1.5mm2  21  18  22  19  22  18
 2.5mm2  28  25  31  26  29  24
 4mm2  38  33  41  35  37  30
 6mm2  49  42  53  45  46  38
 10mm2  67  58  72  62  60  50
 16mm2  89  77  97  83  78  64
 25mm2  118  102  128  110  99  82
 35mm2  145  125  157  135  119  98
 50mm2  175  151  190  163  140  116
 70mm2  222  192  241  207  173  143
 95mm2  269  231  291  251  204  169



    
For sizes greater than 95mm2 refer to Table 4D4A


Table 4F3A – Flexible cords, non-armoured 

Conductor CSA (mm2) Current carrying capacity Max. supported weight (Kg)
See Regs 522.7.2 & 559.6.1.5
1ph ac 3ph ac
0.5mm2 3 3 2
0.75mm2 6 6 3
1mm2 10 10 5
1.25mm2 13 - 5
1.5mm2 16 16 5
2.5mm2 25 20 5
4mm2 32 25 5