Cable Sizing Calculator per AS/NZS 3008.1.1:2017 for Mining Operations
Cable sizing for AS/NZS 3008 mining operations addresses trailing cables for mobile plant, long-distance feeders with significant voltage drop per Table 25, buried cables in high thermal resistivity soils (Table 22 factors down to 0.76 for dry outback conditions), and enhanced earth fault protection requirements mandated by AS/NZS 3007 for underground and open-cut mining installations.
Quick Reference Table
| AS/NZS 3008 Mining Cable Sizing References — AS/NZS 3008.1.1:2017 (2017) | ||
|---|---|---|
| Parameter | Value / Requirement | Clause Reference |
| Buried cable in dry soil | Derating for soil resistivity 2.0-3.0 K.m/W | Table 22 |
| Direct buried current ratings | Single and multicore buried cable ratings | Table 3, Columns 14-16 |
| Long-run voltage drop | mV/A/m for extended feeder lengths | Table 25 |
| Short circuit withstand | Fault current capacity for high-KVA supplies | Clause 3.7, Table 34 |
| Mining-specific requirements | Trailing cables and earth fault protection | AS/NZS 3007, Section 6 |
How to Calculate Cable Sizing for Mining Operations
- 1
Determine the load and feeder length
Identify the connected load (dragline, crusher, conveyor, pump) and the cable route length. Mining feeders commonly run 1-10 km, making voltage drop the dominant sizing criterion.
- 2
Assess soil thermal resistivity
Obtain the soil thermal resistivity at the mine site. Australian outback soils are typically 2.0-3.0 K.m/W when dry. Apply Table 22 correction factors — at 3.0 K.m/W the factor is as low as 0.76.
- 3
Apply buried cable derating
Use Table 3, Columns 14-16 for direct buried cables and apply Table 22 (soil resistivity), Table 21 (depth of burial), and Table 13 (grouping for parallel cables in the same trench).
- 4
Check voltage drop for the full route
For multi-kilometre feeders, voltage drop often governs cable size rather than current rating. Calculate using Table 25 values and verify the receiving-end voltage meets motor starting requirements.
- 5
Verify earth fault protection
Per AS/NZS 3007, mining installations require sensitive earth fault protection (typically 50-100 mA for underground). Size the earth conductor to carry fault current for the protection operating time.
- 6
Consider trailing cable requirements
For mobile plant, select trailing cables rated per AS/NZS 1802 with appropriate mechanical protection. Trailing cables require higher safety margins due to flexing, abrasion, and potential crush damage.
Try the Cable Sizing Calculator
Run compliant AS/NZS 3008.1.1:2017 calculations for mining operations — free, instant results with full clause references.
Calculate Cable Sizing NowBS 7671 vs AS/NZS 3008 Cable Sizing Comparison
| Parameter | BS 7671 | AS/NZS 3008 |
|---|---|---|
| Region | United Kingdom | Australia & New Zealand |
| Voltage drop limit | 3% lighting / 5% other | 5% general (AS/NZS 3000 Table C7) |
| Reference ambient temp | 30°C air | 40°C air (Table 22) |
| Ampacity tables | Appendix 4 Tables 4D1A–4J4A | Tables 13–20 (by method) |
| Derating tables | Ca, Cg, Ci, Cc factors | Tables 22, 24, 25, 26 factors |
| Soil temp reference | 20°C | 25°C (Table 25) |