What is the minimum wire size for a 20 amp circuit?

The minimum wire size for a 20 amp circuit is #12. This is based on the National Electrical Code (NEC), which provides guidelines for safe wire sizes according to the amount of current (amperage) they will carry. For a 20 amp circuit, #12 wire is appropriate because it can safely handle the load without overheating or causing a potential fire hazard.

Using a wire that is too small for the current it carries can lead to excessive heat buildup and electrical failures. #12 wire is typically rated for 20 amps and is commonly used for residential circuits like lighting or receptacle circuits. This ensures that the wire can handle the load while still being within the safety standards established by the NEC.

Thicker wires, like #10, are rated for higher amperages, and while one might use #10 for a 20 amp circuit, it is not necessary and may be impractical for standard applications. Conversely, using a wire size smaller than #12, such as #14 or #16, is not compliant for 20 amp circuits and poses a risk for overheating and failure. Therefore, #12 is the standard and safe choice for a minimum wire size in this scenario.