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Why is AWG's numbering system so special? Uncover the logic behind its numbers!
American Wire Gauge (AWG) is a standardized system for non-metallic conductive wires. It originated in 1857 and is mainly used in North America. Its characteristic is that it is numbered in a logarithmic series, so the increase in number actually means the decrease in wire diameter. This system is critical to the current carrying capacity, as the diameter of the wire directly affects the amount of current it can safely pass.
The origins of AWG are closely related to the manufacturing process, and the original number was determined based on the number of draws required to produce a specific wire gauge.
This means that thinner wire (e.g. 30 gauge wire) needs to pass through more molds during production and therefore has a higher number. Some wire manufacturers used to use their own non-standardized systems, and the standardization of AWG makes choosing the right wire simpler and more sensible. It is worth noting that the AWG system is actually the same as the Brown & Sharpe (B&S) sheet metal gauge, but the latter is designed for use with sheet metal and therefore should not be used on wires.
AWG specifications
In the AWG system, increasing numbers represent logarithmic decreases in wire diameter, similar to British Standard Wire Gauge (SWG). However, AWG is not the same as IEC 60228, which is the metric wire gauge standard used in much of the world and is based directly on the cross-sectional area of the wire.
AWG datasheets only apply to single, solid, round conductors, whereas the AWG of multi-strand wire is determined based on its equivalent solid conductor cross-sectional area.
AWG numbers start at 36 and go up to 0000, with each wire gauge number increasing proportionally in diameter. Specifically, 36 AWG has a diameter of 0.005 inches, while 0000 AWG has a diameter of 0.46 inches. The logic of this numbering system confuses many people as to how to choose the right wire, but in reality, it's easy to navigate as long as you know a few basic rules.
Rules and formulas
Generally speaking, when the cross-sectional area of the wire is doubled, the AWG will be reduced by 3; if the diameter is doubled, the AWG will be reduced by 6. These rules simplify our understanding of wire characteristics. For example, when we need to select wires of different diameters, we do not have to delve into each data, but can use the above rules as a reference.
For example, to find the AWG of a 7 mm square circular wire, just compare it to the corresponding diameter and use a simplified calculation.
The measurement of AWG can also be applied to multi-strand wire, which means that the AWG of the total wire diameter will depend on the diameter and number of each strand. This measurement method allows users to consider different usage requirements when selecting wires.
AWG in daily applications
In daily power applications, AWG numbers not only affect the selection of conductors, but also relate to the safety of the entire system. For example, wires of different diameters may exhibit significantly different performance when faced with overload conditions, so understanding the logic of AWG numbering is a must for any practitioner.
According to U.S. electrical industry standards, conductors over 4/0 AWG are usually expressed in kcmils to further differentiate wire sizes.
Conclusion
Although the logic of AWG numbering is simple, it carries rich technical details. By understanding this system, users can choose the most appropriate wire when facing various power needs. This also triggered our further thinking about wires: In the face of growing power demand, how do you choose the right wires to ensure safety and efficiency?
