Technical Information

Armoured Cables Copper Conductors

Current ratings for three phase and single phase circuits and volt drop at rated current. Twin and multicore XLPE insulated armoured copper cables to BS5467 or BS6724.

Full thermal ratings: Ambient temperature 30°C Conductor operating temperature 90°C

Conductor Cross-Sectional Area Reference Method 1 (clipped Direct) Reference Method 11 (on a perforated horizontal or vertical cable traycable tray) or reference method 13 (Free Air)
1 Two Core Cable* Single-Phase AC or DC 1 Three Core Cable* or 1 Four-Core Cable, Three Phase AC 1 Two-Core Cable* Single Phase AC or DC 1 Three Core Cable* or 1 Four-Core Cable, Three Phase AC
mm² amp amp amp amp
1.5 27 23 29 25
2.5 36 31 39 33
4 49 42 52 44
6 62 53 66 56
10 85 73 90 78
16 110 94 115 99
25 146 124 152 131
35 180 154 188 162
50 219 187 228 197
70 279 238 291 251
95 338 289 354 304
120 392 335 410 353
150 451 386 472 406
185 515 441 539 463
240 607 520 636 546
300 698 599 732 628

VOLTAGE DROP (per ampre per metre):
Conductor operating temperature: 90°C

Conductor Cross-Sectional Area Two-Core Cable DC Two-Core Cable, Single Phase AC Three or Four Core Cable, Three Phase AC
mm² mV mV mV
1.5 31 31 27
2.5 19 19 16
4 12 12 10
6 7.9 7.9 6.8
10 4.7 4.7 4.0
16 2.9 2.9 2.5
    r x z r x z
25 1.85 1.85 0.160 1.90 1.60 0.140 1.65
35 1.35 1.35 0.155 1.35 1.15 0.135 1.15
50 0.98 0.99 0.155 1.00 0.86 0.135 0.87
70 0.67 0.67 0.150 0.69 0.59 0.130 0.60
95 0.49 0.50 0.150 0.52 0.43 0.130 0.45
120 0.39 0.40 0.145 0.42 0.34 0.130 0.37
150 0.31 0.32 0.145 0.35 0.28 0.125 0.30
185 0.25 0.26 0.145 0.29 0.22 0.125 0.26
240 0.195 0.20 0.140 0.24 0.175 0.125 0.21
300 0.155 0.16 0.140 0.21 0.140 0.120 0.185

Ambient Temperature Correction Factors

For Rewireable Fuses Only with XLPE Insulated Cable

Ambient Temperature °C 25 35 40 45 50 55 60 65 70 75 80 85
Correction Factor 1.02 0.98 0.95 0.93 0.91 0.89 0.87 0.85 0.79 0.69 0.56 0.39

For all Other Protective Devices

Ambient Temperature °C 25 35 40 45 50 55 60 65 70 75 80 85
Correction Factor 1.02 0.96 0.91 0.87 0.82 0.76 0.71 0.65 0.58 0.50 0.41 0.29