The thickness of 10 gauge wire can vary depending on the type of wire. According to Birmingham Wire Gauge (BWG), the diameter of 10 gauge wire is approximately 0.1345 inches or 3.4163 millimeters. And according to the American Wire Gauge (AWG) standard, the diameter of 10 gauge wire is approximately 0.102 inches or 2.6 millimeters. It is important to note that BWG is an older standard for measuring wire thickness and is primarily used in the UK, while American Wire Gauge (AWG) is more commonly used in the US and other countries. Please refer to the table below for specific thicknesses.