Guides
Short, worked guides for the calculators. Each one states the inputs, shows the result the tool gives, and cites the clause or table behind it. AmpSize is a design aid. Verify results against the current standard.
For the idea behind a calculation rather than a worked case, read Learn, or see every clause the tools cite on the standards page.
Reader
Tool
5 guides
19 Sept 2026AS/NZS 3000 Clause 3.6.2: voltage drop limitWhat Clause 3.6.2 governs, how the 5 percent budget splits across mains and subcircuits, and a 25 A run over 35 m that returns 2.6 percent from the engine.Voltage DropAS/NZS 3000:2018 Cl 3.6.2AS/NZS 3000:2018 Cl 3.6.2 Note 3AS/NZS 3008.1.2:2017 Cl 4.5Electricity (Safety) Regulations 2010 reg 61
19 Sept 2026Cable size for a 32 A single-phase 25 m runWork through a 32 A single-phase circuit over 25 metres in New Zealand. See every derating factor, the check that sets the size, and the result the tool gives.Cable SizeAS/NZS 3000:2018 Cl 3.4AS/NZS 3000:2018 Cl 2.5.3.1AS/NZS 3000:2018 Cl 3.6.2AS/NZS 3008.1.2:2017 Tables 4-21- 19 Sept 2026Domestic maximum demand with Table C1Assess the maximum demand of a New Zealand house from Table C1, group by group, with a worked example that lands on 52.61 A on a single-phase supply.Maximum DemandAS/NZS 3000:2018 Cl 2.2AS/NZS 3000:2018 Table C1
19 Sept 2026Earth 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.Loop ImpedanceAS/NZS 3000:2018 Cl 5.7.4AS/NZS 3000:2018 Table 8.1AS/NZS 3000:2018 Table 5.1- 19 Sept 2026Voltage 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.Voltage DropAS/NZS 3008.1.2:2017 Cl 4.5AS/NZS 3000:2018 Cl 3.6.2AS/NZS 3008.1.2:2017 Tables 30-35