Something that has been a constant source of confusion within many circles, is the question of why do wire gauge sizes seem to be the opposite of what we think they should be? As a wire increases in physical width the gauge of that wire will decrease in numerical value. This seems backwards but, there must be an explanation to this that makes some form of sense.

Determining Wire Gauge Sizes 

Given an example of the wire gauge chart in Figure 1.1 we can see there is an extreme difference in physical size between a 0 gauge wire and that of a 30 gauge wire. The physical size of the 30 gauge is substantially smaller than that of the 0 gauge wire. Why is this?

The physical size of a wire is defined by the number of operations that it takes to get it to that physical size. This process means that a 30 gauge wire is much smaller in size than a 0 gauge wire. This process is called “Wire Drawing” and it looks like Figure 1.2. “Wire Drawing” is what gives us all of the different gauges that are seen in Figure 1.1.

A way to think about the wire drawing process is to think of the process of taffy pulling. Just like that sugary deliciousness, the wire starts off as one larger wire mass. Also, like taffy pulling wire drawing stretches and decreases the physical size of the wire making it longer and thinner. The process of wire drawing and decreasing the gauge of a wire also reduces the current that is traveling through the wire. By reducing the current in smaller gauged wires there is a decrease in the amperage that can be handled.


wire gauge

Figure 1.1 (Standard Wire Gauge Chart)


Figure 1.2 (Wire Drawing to Decrease Wire Gauge) (Kingway)


Now that you know how wire gauges are measured you are ready to start your own wire harness journey!

If you are interested in designing your own wire harnesses check out our new Wire Harness Estimator to get a quote!

If you need more information before you get started check out our blog on The Wire Harness Estimator Components Defined.

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