As: 3008 Cable Selection Link

Cable sizing is not just about the thickness of the wire. Under AS/NZS 3008.1.1, you must perform three distinct calculations, and the result of these three becomes your minimum compliant cable size.

However, compliance with AS 3008 extends beyond simply preventing the cable from burning out; it also ensures the efficient operation of the connected equipment through voltage drop calculations. As electricity travels along a cable, some voltage is inevitably lost due to the conductor's impedance. If the voltage at the load end drops below a certain threshold (typically 5% for consumers' mains or sub-mains), equipment performance suffers. Motors may overheat or fail to start, and sensitive electronics may malfunction. AS 3008 provides specific tables for voltage drop (mV/A/m) that allow engineers to calculate the cumulative loss over the cable length. Often, a cable that is sufficient for ampacity may prove too small to meet voltage drop limits over a long distance, necessitating an increase in conductor size to ensure power quality. 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. Cable sizing is not just about the thickness of the wire