Cable Size Calculator AS/NZS 3008
Estimate load current, active cable size, earth size, voltage drop, and short-circuit suitability using an AS/NZS 3008 style calculator layout.
Cable Size Calculator AS/NZS 3008
Enter supply, cable, installation, and protection details to estimate cable sizing and voltage drop.
Standard parameters
- Part 1: Australian conditions. Air 40°C, soil 25°C.
- Part 2: New Zealand conditions. Air 30°C, soil 15°C.
- Differences are reflected in rating assumptions and environmental defaults.
Load and voltage-drop notes
- For three-phase systems, enter per-phase line current when rating is in amperes.
- Distance is one-way cable length from source to load. Return path is reflected in the simplified voltage-drop logic.
- Power factor affects current conversion when load is entered in kW or hp.
Cable sizing notes
- Auto size selects the smallest listed conductor that satisfies the simplified current carrying requirement.
- Voltage-drop status compares the estimated percentage against your entered maximum limit.
- Earth size can be selected manually or automatically estimated from the active conductor size.
How to Use
- Select the applicable standard and supply phase.
- Enter voltage, load rating, and power factor.
- Choose conductor, insulation, and installation details.
- Set voltage-drop and short-circuit check values.
- Click Calculate to estimate cable size and results.
About This Calculator
This calculator provides a practical estimation workflow for cable selection using AS/NZS 3008 style inputs. It helps users compare load current, cable size, earth size, and voltage-drop limits in one place.
Frequently Asked Questions
Does this calculator give a certified design result?
No. It is an estimation tool for planning and learning. Final design should always be checked by a qualified professional.
What does Auto cable size mean?
Auto selects the smallest listed conductor size that satisfies the simplified current carrying rule in this calculator.
What happens if voltage drop exceeds the allowed limit?
The result will show FAIL for voltage drop, indicating that a larger cable or different installation choice may be needed.