According to the National Electrical Code, what is the minimum wire size that may be used safely for wiring with a 20-ampere circuit breaker?

The National Electrical Code (NEC) determines the safe current-carrying capacity, or ampacity, of electrical wires to prevent them from overheating and causing structural fires. In the American Wire Gauge (AWG) system, a lower number indicates a thicker wire capable of safely carrying more current. For a standard 20-ampere household circuit, AWG number 12 is the minimum safe wire size. Using a thinner wire, such as AWG 14, 16, or 20, is extremely dangerous because the wire could overheat and start a fire long before the 20-amp circuit breaker trips. While AWG 8 is physically thicker and would safely carry the current, it is not the minimum size required.