EC21 Product Catalogs - national o ring gauge http://www.ec21.com/ec-market/national o ring gauge.html Buried Service Wirehttp://zhouhunan.en.ec21.com/Buried_Service_Wire--3725500_3725574.htmlGauge (AWG), the nominal diameters are stated: Conductor Size (AWG) Nominal Diameter Inch (mm) 19 0.0359 (0.91220090806