Code of Practice for the Electricity (Wiring) Regulations - 2009 Edition

Table 11(4)
Minimum Cross-sectional Area of Protective Conductor for
Circuits Protected by HBC Fuses to BS1361
Fuse Rating (Amp) 5 15 20 30 45 60 80 100
Minimum cross-sectional
area (sq. mm) of
Copper 1 1 1.5 2.5 4 10 10 16
protective conductor for
5 sec. disconnection
Aluminium 16 16 16 16 16 16 16 25
Minimum cross-sectional
area (sq. mm) of
protective conductor for
0.4 sec. disconnection
0.2 0Zs 0.03
0.13Zs0.2 0
0.08Zs0.13
0.05Zs0.08
0.03Zs0.05
0.02Zs0.03
0.00Zs0.02
Copper 1 1 1 1 2.5
Table 11(5)
Minimum Cross-sectional Area of Protective Conductor for Circuits Protected
by Miniature Circuit Breaker Type 1 & 2 to BS 3871 or Equivalent
Earth Fault Loop
Impedance Zs (ohm)
Minimum Cross-sectional Area of Protective Conductor (mm2 )
for 5 Sec. and 0.4 Sec. Disconnection
Copper Aluminium
1 .000
1.5 00
2.5 00
4.0 00
6.0 00
10 .00
16 .00
Table 11(6)
Minimum Cross-sectional Area of Protective Conductor for
Circuit Protected by Miniature Circuit Breaker (MCB) Type 3,
Type B & Type C to IEC 60898 or Equivalent
MCB Rating (Amp) 05
10 15 20 30 50 60 80 100
Minimum cross-sectional
area (sq. mm) of
Copper 01
1.5 2.5 2.5 4 10 10 16 16
protective conductor for
5 sec. disconnection
Aluminium 16 16 16 16 16 16 16 16 25
Minimum cross-sectional
area (sq. mm) of
protective conductor for
0.4 sec. disconnection
(Please refer to Table 11(5))
80
16
16
16
16
16
16
25