Reference Table 5.1 in AS/NZS 3000:2018
Nominal Size of Active Conductor (mm2) |
Nominal Size of Earth Conductor with 'Cu' Active Conductor (mm2) |
Nominal Size of Earth Conductor with 'Al' Active Conductor (mm2) |
1 |
1a |
- |
1.5 |
1.5a |
- |
2.5 |
2.5 |
- |
4 |
2.5 |
- |
6 |
2.5 |
- |
10 |
4 |
- |
16 |
6 |
4 |
25 |
6 |
6 |
35 |
10 |
6 |
50 |
16 |
10 |
70 |
25 |
10 |
95 |
25 |
16 |
120 |
35 |
25 |
150 |
50 |
25 |
185 |
70 |
35 |
240 |
35 |
50 |
300 |
120 |
70 |
400 |
≥120b |
≥120b |
500 |
≥120b |
≥120b |
630 |
≥120b |
≥120 |
Special Notes:
a - These earthing conductors shall only be used where incorporated in a multi-core cable or flexible cord, other than a lift travelling cable, in accordance with Clause 5.3.3.4, Items (b) and (c).
b - A larger earthing conductor may be required to satisfy Clause 5.3.3.1.1.
c - Refer Section 5.3.3 in AS/NZS 3000:2018 for more information on earthing conductor size.