Staff of Research and Education Associationġ. Reference: Handbook of Scientific and Engineering Data Cross-sectional area for busbars is typically rated in terms of circular mils (even for square and rectangular bars!), most likely for the convenience of being able to directly equate busbar size with round wire. Although a square or rectangular cross-section is very common for busbar shape, other shapes are used as well. Busbars are usually made of copper or aluminum, and are most often uninsulated. In these instances, thick bars of solid metal called busbars are used as conductors. Stranded wire construction is favored, instead.įor some high-current applications, conductor sizes beyond the practical size limit of round wire are required. This is a handy rule to remember when making rough wire size estimations!įor very large wire sizes (fatter than 4/0), the wire gauge system is typically abandoned for cross-sectional area measurement in thousands of circular mils (MCM), borrowing the old Roman numeral 'M' to denote a multiple of 'thousand' in front of 'CM' for 'circular mils.' The following table of wire sizes does not show any sizes bigger than 4/0 gauge, because solid copper wire becomes impractical to handle at those sizes. The American Wire Gauge (AWG) measurement system was designed with a purpose: for every three steps in the gauge scale, wire area (and weight per unit length) approximately doubles. Instrumentation, Electrical, Control and Sensing DevicesĪWG Copper Wire Table Size and Data Chart 100 Degrees F AWG Copper Wire Size and Data Table Chart 100 Degrees F

Wire gauge chart size