Wire Sizes: In North American practice, wire sizes are commonly specified using which standard?

• A. Metric Units
• B. Color Coding
• C. American Wire Gauge
• D. Inch-Per-Meter

Answer: (C)

In North American practice, wire sizes are specified using American Wire Gauge because it is the established system that directly ties a gauge number to a precise conductor diameter and cross-sectional area (in circular mils). This makes it easy to compare conductors, reference ampacity and voltage-drop tables, and match products from manufacturers and codes. The gauge numbering is consistent across sizes, with smaller numbers meaning larger wires, and each step corresponds to a defined diameter. The other options don’t provide this standardized sizing framework: metric mm² is used abroad but isn’t the NA convention; color coding relates to insulation color, not size; and Inch-Per-Meter isn’t a recognized sizing standard.