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

Table 11(2)
(a) Minimum Cross-sectional Area of Protective Conductor in Relation
to the Cross-sectional Area of Associated Phase Conductor
Cross-sectional Area of
Phase Conductor
Minimum Cross-sectional Area of the
Corresponding Protective Conductor
If the Protective Conductor is of If the Protective Conductor is not
the Same Material as the Phase the Same Material as the Phase
(S) Conductor Conductor
mm 2 mm 2 mm 2
S16 S
16S35 16
S35
S—
2
k 1 S
——
k 2
k 1 16
——
k 2
k 1 S
——
k 2 2
Note: For values of k 1 and k 2 , please refer to tables 11(2)(b), (c), (d ), (e) and ( f ).
(b) Values of k for insulated protective conductor not incorporated in a cable
and not bunched with cables, or for separate bare protective conductor in
contact with cable covering but not bunched with cables where the
assumed initial temperature is 30°C
Material of conductor
Copper
Aluminium
Steel
Assumed initial temperature
Final temperature
* Above 300mm 2
Insulation of protective conductor or cable covering
70°C
thermoplastic
143/133*
95/88*
52
30°C
160°C/140°C*
77
90°C
thermoplastic
143/133*
95/88*
52
30°C
160°C/140°C*
90°C
thermosetting
176
116
64
30°C
250°C