Increasing gauge numbers denote decreasing wire diameters, which is
similar to many other non-metric gauging systems such as British
Standard Wire Gauge (SWG), but unlike IEC 60228, the metric wire-size
standard used in most parts of the world.


This gauge system originated in the number of drawing operations used to
produce a given gauge of wire. Very fine wire (for example, 30 gauge)
required more passes through the drawing dies than 0 gauge wire did.
Manufacturers of wire formerly had proprietary wire gauge systems; the
development of standardized wire gauges rationalized selection of wire
for a particular purpose. -- Wikip

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