25 / 26 Voltage Drop (Per Amp Per Meter) according to BS 7671:2008 table 4D1B 2 cables, single-phase a.c. 3 or 4 cables, three-phase a.c. Nominal Ref. Methods C & F Ref. Methods A Ref. Methods C & F(clipped Ref. Methods A Cross 2 cables (clipped direct, on trays or in free air) and B (enclosed direct, on trays or in free air) & B (enclosed Section d.c. in conduit or in conduit or Cables Cables Cables Cables Area Cables touching trunking) trunking spaced* touching, Trefoil touching, Flat spaced*, Flat 1 mm
2
2
3
4
5
6
7
8
9
mV/A/m
mV/A/m
mV/A/m
mV/A/m
mV/A/m
mV/A/m
mV/A/m
mV/A/m
1.0
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
4.0
11
11
11
11
9.5
9.5
9,5
9.5
6.0
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
r
x
z
r
x
z
r
x
z
r
x
z
r
x
z
r
x
2.4 z
r
x
z
25
1.75
1.80 0.33 1.80 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 1.30 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 0.3
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 0.16 0.57 0.55 0.24 0.6 0.55 0.31 0.63
1.0
0.93 0.19 0.95 0.93 0.28 0.97 0.81 0.26 0.85 0.8 0.165 0.82 0.8
0.24 0.84 0.8 0.32 0.86
95
0.46
0.49 0.28 0.56 0.47 0.18 0.5 0.47 0.27 0.54 0.42 0.24 0.48 0.41 0.155 0.43 0.41 0.23 0.47 0.4 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 0.15 0.36 0.32 0.23 0.4 0.32 0.3 0.44
150
0.29
0.31 0.27 0.41
185
0.23
0.25 0.27 0.37 0.24 0.17 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 0.3 0.36
240
0.18 0.1950.26 0.33 0.185 0.165 0.25 0.185 0.25 0.31 0.17 0.23 0.29 0.16 0.145 0.22 0.16 0.22 0.27 0.16 0.29 0.34
0.3 0.175 0.34 0.29 0.26 0.39 0.27 0.23 0.36 0.26 0.15 0.3 0.26 0.23 0.34 0.26 0.3
Note: *Spacings larger than one cable diameter will result in a large voltage drop. r = conductor resistance at operating temperature x = reactance z = impedance
600/1000V
Rated Voltage
N BS 6231
Standard
Flame Retardancy BS EN 60332-1-2
0.4