Which wire gauge size has the largest diameter?

The wire gauge size with the largest diameter is, in fact, 18. In the American Wire Gauge (AWG) system, a lower gauge number indicates a larger diameter wire. Therefore, among the options provided, the 18 gauge wire has a larger diameter compared to 20, 22, and 24 gauge wires.

The AWG system is designed such that as the gauge number increases, the diameter of the wire decreases. For instance, 20 gauge wire is smaller in diameter than 18 gauge wire, and similarly, 22 and 24 gauge wires are even smaller. This is important in applications where current carrying capacity, resistance, and power loss need to be considered. Using a wire with an appropriate diameter ensures safe and efficient operation of electrical systems.