Tip. Remember, wire gauge is measured and labeled so the lower the number is, the thicker the wire is. This means gray wire nuts are for the smallest wires, and red ones are for the largest.

Gauge Sizes. Wire size refers to a wire’s diameter, which is often measured according to the American Wire Gauge (AWG) measurement system. AWG sizes range from 0000 to 40.

Low energy-draw fixtures like lights and bedroom outlets will use 14 American Wire Gauge (AWG) with 15 amp circuits. 12 AWG wire will be used with 20 amp circuits to provide a bit more power to ...