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How far can 1.5 mm² run on a 10 A circuit?

Maximum circuit length calculator

+1 reference

Worked to AS/NZS 3000:2018. Tables checked 26 Sept 2026.

Maximum route length

34.85m

Fault loop route length
82m
Governing check
Voltage drop
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This result is a design aid. Verify it against the current standard.

A drawn result card from the Maximum Circuit Length tool: maximum route length 34.85 m.

A 1.5 mm² copper circuit on a 10 A curve C breaker can run 34.85 m at its full load. Voltage drop sets that length: at 34.85 m the drop reaches the 5 % limit of AS/NZS 3000:2018 Cl 3.6.2.

The case

The circuit is single‑phase at 230 V with a 1.5 mm² earth and a design current of 10 A at a power factor of 1. AS/NZS 3000:2018 Table B1 gives a fault loop length of 82 m for this cable and device, so the loop is not the limit here.

What changes the answer

The real load is often lower than the breaker. A lighting circuit that draws less current can run further before the drop reaches the limit.

A larger cable runs further. 2.5 mm² on the same breaker reaches the limit at 63.82 m.

See also: What size cable for a lighting circuit in NZ? and Maximum length of a 20 A final subcircuit.

Try it with these inputs

Active conductor
1.5 mm²
Design current
10 A
Protective device
Type C circuit-breaker
Earth conductor
1.5 mm²
Insulation
PVC
Phases
Single phase
Power factor
1
Device rating
10 A
Voltage drop limit
5 %
Nominal phase voltage
230 V
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