How To Measure Wire Gauge With Calipers? 3 Steps you Should Read

Wire gauge refers to the measurement of wire diameter. In electrical applications, wires vary in diameters to accommodate different amounts of current and voltage. High current or voltage passage creates a higher heat trail. You would need thicker wires to compensate for it. In this article, we will discuss how to measure wire gauge with calipers.

How Is Wire Gauge Measured?

Step 1. Remove The Insulation

Before taking diameter measurements of a wire, you need to get rid of the insulation. Use wire cutters to cut wire ends. Make half an inch deep cuts to reach the insulation, clip around the insulation perimeter and remove it from the end of the wire.
You must make sure that nothing gets left behind and the wire in the clipped region is completely exposed.


Step 2. Place The Calipers Jaws On The Wire

Take a slide caliper and extend its jaws wider than the diameter of the wire. Then slowly begin to close them until they come in contact with the wire. Check the reading on the millimeter scale of the calipers and write it down.
Repeat this process in a few other bare wire regions for the sake of higher measurement accuracy.

how to measure wire gauge with caliper


Step 3. Consult A Conversion Chart

The measurements you got from the slide caliper might seem meaningless to the naked eye. You have to convert these values using a conversion chart and make them sensible for your purpose.
For instance, if you find 289 millimeters in your calipers, it would translate into 1 gauge. You can make these conversions using an appropriate conversion chart.

What Instrument Is Used To Measure The Thickness Of A Wire?

You can use multiple instruments to measure the thickness of a wire. You can use a slide caliper

 just as we demonstrated. But for smaller diameters, using a micrometer screw gauge would be a better option. 
You can also use a wire gauge, which has multiple slots, each marked with their respective diameters, through which you can insert wires.

For this task you can use 

GENERAL TOOLS 729 Slide Caliper, 4"

Digital Micrometer, Professional Inch/Metric Thickness Measuring Tools


How Is Cable Size Measured?

Knowing the size of a cable is crucial to determining its current rating. Without knowing this, you might fall victim to circuit overload if you accidentally run more current through the cable than it can actually handle.


For example, a 1.5mm cable can carry 14 amperes of current. Anything above it, you are asking for trouble.


The thicker the wires get, the lesser their resistance gets. Meaning, thicker wires can conduct more electricity. Measure the diameter of the cross-sectional area of the wire and compare that data with a cable size-current rating comparison chart to find out its current rating. You can use a slide caliper to measure the cross-sectional area of the cable.


How Do I Know If My Wire Is 12 or 14 Gauge?


You can always take measurements and consult the comparison chart to know for sure. But, if time is of the essence, you can use a simple trick to tell the difference. A 12 gauge wire would have the same thickness as a nickel, while the 14-gauge wire would match the thickness of a dime.

Final Say
Measuring the wire gauge is imperative to choosing the suitable wire for your work. Hopefully, this article will help you measure wire gauges with maximum accuracy.

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