A wire gauge is a hand-held measuring device which can be circular or rectangular. It has a number of cut-out sections around its perimeter which correspond to a range of diameters.
A series of notches, ranging from small to large, is arranged around the perimeter of a wire gauge. Each notch is inscribed with a measurement. Further in from the edge, each notch widens out into a circle to create a wire run-through area. A wire can be pushed into the run-through area when it has been measured in the precise diameter cut out, this helps to release it from the gauge.
A wire gauge is used to precisely identify the diameter of wire. A length of wire can be held against the gauge to see which gap forms a snug fit. The best-fitting gap identifies the ‘gauge’ or diameter (in millimetres) of the wire. The larger the gauge number, the smaller the diameter or thickness – for example, 0 indicates the largest diameter of wire that some gauges can measure.
