Wire gauge

But the Birmingham and the Lancashire gauges, the latter being based on an averaging of the dimensions collated from a large number of the former in the possession of Peter Stubs of Warrington (1756-1806),[2] have long held the leading position, and are still retained and used probably to a greater extent than the more recent geometrical gauges.

The first attempt to adopt a geometrical system was made by Messrs Brown & Sharpe in 1855.

[3] The Imperial Standard Wire Gauge, which was sanctioned by the British Board of Trade in 1884, was formulated by J. Latimer Clark.

The IEC 60228, used in most parts of the world, defines standard wire sizes based on their cross-sectional areas as expressed in mm2.

[3] In commerce, the sizes of wire are estimated by devices, also called gauges, which consist of plates of circular or oblong form having notches of different widths around their edges to receive wire and sheet metals of different thicknesses.

The circular forms of wire gauge measurement devices are the most popular, and are generally 3+3⁄4 inches (95 mm) in diameter, with thirty-six notches; many have the decimal equivalents of the sizes stamped on the back.

In some cases both edges are graduated differently in order to allow comparison between two systems of measurement.

Advantages of this system include the ability to readily calculate the physical dimensions or weight of wire, ability to take account of non-circular wire, and ease of calculation of electrical properties.