On Friday, February 9, 2018 at 2:00:26 AM UTC-5, micky wrote:
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

Did all know this?

A-merican W-ire G-auge

Somewhere between Caliber (which is fractions of an inch) and arbitrary convention. Once upon a time, wire was measured in fractions-of-whatever, much as railway timetables were arbitrary and based on local time. After a large number of crashes, railroads created a convention which is now GMT.

And, US wire manufacturers adopted a similar convention so as to be able to sell products beyond their back yards - somewhere just before the Civil War as I remember - mid 1850s or so.

https://www.rapidtables.com/calc/wir...uge-chart.html

Peter Wieck
Melrose Park, PA