In the American Wire Gauge or "AWG" system, as the wire gets smaller, the number of the wire gets larger. The smallest AWG size is 40 and looks like a metal thread.

Wire Size Graphic

Extension Cord Picture Common electrical extension cords on lamps are typically 18 gauge wire. The smallest gauge allowed for lighting and receptacle circuits in a house is 14 gauge wire. The gauge sizes get smaller with corresponding increases in the wires diameter all the way down to 0 gauge.

At that point, the industry labeled the next larger size as double zero, commonly referred to as 2 ought. The next AWG size larger than 2 ought is triple zero or 3 ought. Four ought is the largest AWG wire size designation. Wires larger than this size are designated by the Thousand Circular Mill system or "KCMIL" sizes.