Tables for Earth Sizing and Cables in Conduit

Minimum Size of Copper Earthing Conductors

Nominal area active conductors mm2 For copper active conductors mm2 For aluminium active conductors mm2
1 1.0*
1.5 1.5*
2.5 2.5
4 2.5
6 2.5 2.5
10 4 2.5
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 95 50
300 120 70
400 120 95
500 120 95
630 120 120

*Refer Wiring Rules, AS/NZS 3000 regarding 1.5 earthing conductors.

Number of Cables in Conduit.

Calculated maximum number of thermoplastic insulated and sheathed single core copper or aluminium cables permitted in metallic and non-metallic conduit or pipe.

1.0 to 25mm2 450/750V to AS/NZS 5000.2

35 to 630mm2 0.6/1kV to AS/NZS 5000.1

Nominal Nominal size of conduit (mm)
area 20 25 32 40 50 63 80 100 150
mm2 HD HD HD HD HD HD HD HD HD
1 5 9 16 27 43 72 152
1.5 4 7 13 22 36 59 126
2.5 3 5 10 16 27 44 93 155
4 2 4 7 12 19 32 67 112
6 1 3 6 9 16 26 56 93
10 1 2 4 7 11 18 40 66 131
16 1 1 3 5 8 14 30 51 100
25 1 2 3 5 9 19 32 64
35 1 1 2 4 7 16 27 54
50 1 2 3 6 13 21 42
70 1 1 3 4 10 17 34
95 1 2 3 7 12 24
120 1 1 3 5 9 19
150 1 1 2 4 8 16
185 1 1 4 6 13
240 1 1 3 5 10
300 1 2 4 8
400 1 2 3 6
500 1 2 5
630 1 2 4

Notes: 1. For PVC flexible conduits, the recommendations are based on conduits used without fittings or with fittings only at the ends of the conduit run. Where intermediate fittings are used in a run of PVC flexible conduit, an appropriate reduction should be made in the number of cables drawn into the conduit. 2. One earth wire of appropriate size, as determined by the requirements of AS/NZS 3000, may be inserted in all conduits, provided that its insertion does not prevent easy drawing in of cables. 3. Table suitable for use with Olex manufactured product only.

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Tables for Earth Sizing and Cables in Conduit