AS 3008.1 (the current version) is the for selecting cables (LV up to 0.6/1 kV). If you work in building services, industrial power, or renewable energy in Australia/NZ, you cannot legally or practically design circuits without it.
if you’re an Australian electrical professional. Don’t expect an easy read – but once mastered, it’s the only correct way to size cables for safety, voltage drop, and thermal limits. as 3008 cable selection
For long runs, voltage drop is often the determining factor. It ensures that the voltage at the load remains within functional limits—typically a 5% maximum drop from the point of supply for most installations. AS 3008