What is AWG? Why is AWG an important parameter when choosing cables?

When buying cables, there is an important parameter to consider, which is the American wire gauge (AWG), such as 12 AWG, 18 AWG, 24 AWG, etc. So, what is AWG? Why is AWG an important parameter for buying cables? This article will give the answers one by one.

Definition of AWG

AWG is a standard for distinguishing wire diameters, also known as Brown Sharpe wire gauge. This standardized wire gauge system has been used in the United States since 1857 and has now been adopted by most countries. The AWG wire number (the number in front of AWG, such as 24AWG, 26AWG, etc.) indicates the number of holes that the wire must pass through before it forms its maximum diameter. The larger the number, the more holes the wire passes through and the smaller the diameter of the wire. Generally, the wire number of a single-wire conductor is determined by the diameter, while the wire number of a stranded wire is determined by the cross-sectional area. The larger the cross-sectional area, the greater the current that the cable can transmit and the longer the transmission distance. The thumb rule of AWG is: for every increase of 6 in the wire number, the cable diameter doubles; for every increase of 3 in the wire number, the cross-sectional area doubles.

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Note: In the optical communication industry, AWG is also the abbreviation of arrayed waveguide grating (AWG). The two should be distinguished according to actual conditions.

AWG wire diameter comparison table

The following table lists in detail the wire diameter, cross-sectional area, resistance value, maximum current value and maximum frequency of different AWG values:

AWG wire size calculation

The relationship between AWG value and wire diameter is detailed in the ASTM B 258-02 technical specification. From the table above, we can see that the diameter of 36AWG is 0.005 inches, and the diameter of 0000AWG is 0.46 inches. The ratio of the two diameters is 1:92. In addition, there are 39 wire numbers between 36AWG and 0000AWG. From these values, we can derive the AWG wire number n through the following formula:

Wire diameter calculation

The formula for calculating the wire diameter of AWG No. n is:

Wire cross-sectional area calculation

The calculation formula for the cross-sectional area of ​​a wire of size n AWG is:

Wire resistance calculation

The formula for calculating the wire resistance of AWG size n is:

Common AWG

As can be seen from the AWG wire diameter comparison table above, there are 44 wire size standards for AWG, but only some of these AWG wire sizes are more common in various applications. The following table lists in detail the cable types corresponding to common AWGs:

Conclusion

AWG is an important parameter for measuring cables. Cables of different AWGs have different applications. Therefore, before purchasing cables based on AWG, you must be clear about what kind of cable should be used for specific applications.