Question 1

Do I use copper cross-section (CSA) or overall cable diameter for conduit fill?

Accepted Answer

Use the overall outside cable diameter including insulation. The 6 mm² value is the copper CSA and is not used for conduit fill calculations per AS/NZS 3000:2018.

Question 2

What space factor do I apply?

Accepted Answer

AS/NZS 3000:2018 Clause 3.5.2.2 — 53% for a single cable, 31% for two cables, and 40% for more than two cables in a conduit.

AS/NZS 3000 conduit calculator

System setup

Conduit selection

Cable details

Result