Electrician's Licensing Practice Exam

In the standard U.S. system of wire sizes, what does a lower number indicate?

1. Thinner wire

2. Thicker wire

3. Higher voltage rating

4. Increased insulation

The correct answer is: Thicker wire

In the American Wire Gauge (AWG) system, which is the standard for wire sizing in the United States, a lower gauge number corresponds to a thicker wire. This is a fundamental aspect of the wire sizing system, where each decrease in gauge number represents a significant increase in the diameter of the wire. For example, a wire sized at 10 AWG is thicker than one sized at 12 AWG. Thicker wires can carry more current and have lower resistance, making them better suited for higher power applications. It's important for electricians to understand this relationship, as selecting the correct wire size is crucial for safety and efficiency in electrical installations. The other options do not reflect the relationship defined by the AWG system; a higher voltage rating is not indicated by wire gauge numbers, nor is there a direct correlation between wire gauge and insulation thickness in this context.