As/nzs 3008 Jun 2026

In practice, for runs longer than 30–50 metres in residential/commercial, (Section 3 of AS/NZS 3008.1.1) will force you to upsize the cable long before ampacity becomes an issue.

For cables <16 mm², reactance ($X$) is negligible – just use resistive drop. For >35 mm², reactance becomes dominant, especially for power factor <0.8. Many engineers forget this and under-size large motor feeders. as/nzs 3008

The standard is typically divided into two parts: In practice, for runs longer than 30–50 metres