Engineer guides
Checking a design, producing evidence and comparing candidate cable sizes for a job.
- 6 min readAS/NZS 3008.1.1 table numbers: 2017 to 2025Each AS/NZS 3008.1.1 table AmpSize reads, with its 2017 number, its 2025 number and whether its values moved, and one submain that cites both sets.
- 4 min readAS/NZS 3008.1.1 vs 3008.1.2: AU and NZ conditionsThe AU part of AS/NZS 3008.1 rates cable at 40 °C air and the NZ part at 30 °C. One 32 A circuit needs 6 mm² in Australia and 4 mm² in New Zealand.
- 5 min readAS/NZS 3008 vs BS 7671: cable sizing comparedHow BS 7671 and AS/NZS 3000 with AS/NZS 3008.1 size a cable, where they differ, and why a BS current rating never converts into an AS/NZS one.
- 5 min readDC cable size: 48 V battery and 600 V PV arrayTwo d.c. circuits sized to AS/NZS 3008.1.1:2025, a 48 V battery-to-inverter run that current sizes and a 600 V array feed that voltage drop sizes.
- 3 min readProspective fault current at a main switchboardA 16 kA fault cleared in 0.1 s on 70 mm² copper XLPE, with the minimum conductor size, the withstand current and the k factor the adiabatic check returns.
- 5 min readAS/NZS 3008.1.1:2025: what changed from 2017The 2025 AU part adds d.c. ratings to 1500 V, renumbers every table and moves some ratings. Four circuits, each run on both editions, show what moves.
- 3 min readVoltage rise for a 5 kW solar inverter cableA 5 kW single-phase inverter 40 m from the switchboard on 10 mm² copper, with the rise in volts, the percent and the maximum length the tool returns.
- 4 min readEarth fault loop impedance and maximum ZsWhat earth fault loop impedance measures, how the maximum Zs check works, and a 32 A circuit on 6 mm² over 25 m that lands on 0.67 ohms against a 0.96 limit.
- 3 min readVoltage drop with the mV/A·m methodHow the millivolt per amp metre method works, with a 32 A run over 25 metres on 6 mm² copper and the exact drop, percent and maximum length the tool returns.
Calculators these guides use
- Cable size calculatorFind the smallest cable size that passes each check.
- DC cable size calculatorSize a d.c. cable up to 1500 V for current and voltage drop.
- Cable fault rating calculatorCheck that a conductor can withstand the fault current.
- Voltage rise calculatorCalculate voltage rise for embedded generation or PV.
- Earth fault loop impedance calculatorCheck earth fault loop impedance against the maximum Zs.
- Voltage drop calculatorCalculate voltage drop on a cable run and check the limit.