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Cable size · AS/NZS 3008

Size the cable. See what governs.

Checks current-carrying capacity, voltage drop and optional short-circuit withstand together, then shows why the selected cable won.

Design inputs

Start with the actual load rating and one-way route length.

Derating, parallels and fault withstand
Use the product of applicable standard factors.

01 · Design current

Converts A, kW or kVA to current. Three-phase uses I = P / (√3 × V × PF).

02 · Voltage drop

Uses cable R and X with the specified power factor. The one-way length is multiplied by 2 for single-phase or √3 for three-phase.

03 · Final selection

Returns the first standard size that passes every enabled check, and identifies the largest minimum as the governing constraint.

Design limitation. This calculator deliberately covers a defined common configuration rather than pretending to cover every AS/NZS 3008 table. Verify the final selection against the complete current standard, cable manufacturer data, earth size, grouping, ambient conditions, protection and site conditions.