How much larger must aluminum conductors be sized compared to copper conductors for the same amperage?

When comparing aluminum conductors to copper conductors for the same amperage, aluminum conductors must be sized larger due to several key factors. Aluminum has a higher resistivity compared to copper, which means that for the same amount of electrical current, aluminum will generate more heat and therefore requires a larger conductor size to safely carry that current without overheating.

The increased size compensates for aluminum's poorer conductivity, ensuring that voltage drop is minimized, and that the conductor can handle the thermal and mechanical stresses associated with that electrical load. Typically, aluminum conductors are around 1.5 times larger in diameter than copper conductors for the same amperage, although exact sizing can depend on specific conditions like local codes, installation methods, and ambient temperature.

In contrast, other options suggest either sizing smaller, keeping them equal, or making them half the size, which does not accurately reflect the necessary adjustments due to the inherent material differences between aluminum and copper. Thus, sizing aluminum conductors larger is essential for both safety and functionality in electrical installations.