The chart is based on solid wire. Stranded wire (more flexible) has a slightly larger overall diameter for the same gauge. Most printed charts omit this, leading to DIYers buying stranded wire that won’t fit into a push-in connector.
In electrical engineering, the selection of conductors is governed by the need to minimize energy loss while ensuring mechanical durability and safety. The American Wire Gauge system, also known as the Brown & Sharpe wire gauge, establishes a standardized method for designating wire diameters. awg wire size chart
The following table lists the most common AWG sizes used in industry. Data includes diameter, cross-sectional area, resistance per 1,000 feet (at 20°C), and standard ampacity ratings for chassis wiring (single conductor in free air) and power transmission. The chart is based on solid wire