Question 1

Why does a smaller AWG number mean a larger wire?

Accepted Answer

The AWG system originated from the number of drawing dies a wire was pulled through during manufacturing. A larger number of drawing passes produced thinner wire, hence higher gauge numbers correspond to smaller diameters. This counterintuitive convention has persisted since the 19th century.

Question 2

How does aluminum wire compare to copper wire of the same gauge?

Accepted Answer

Aluminum has 61% the conductivity of copper, so for the same current capacity you need to increase the wire size by approximately 2 AWG steps (e.g., use AWG 10 aluminum where AWG 12 copper would suffice). Aluminum is lighter (30% the weight of copper) and less expensive, making it common in power distribution, but requires special connectors to prevent galvanic corrosion.