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American Wire Gauge

by Amy on December 20th, 2012

The United States has set some standards for measuring the wire gauge of electrical wiring called the American Wire Gauge (AWG). This is the size of a copper wire that is used in electrical applications. This standard was needed in order for everyone to be able to use a standard measurement of wiring across manufacturers and across locals.

Wire Gauge Sizes

Determine the size of the wire based on gauge number can be confusing. The best way to remember is: The higher the gauge number, the smaller the diameter of the wire is. For instance, a 0000 wire is 0.4600 inches in diameter but a 14 gauge wire has a diameter of 0.0641 inches. I realize that this is counter intuitive, but if you remember, bigger gauge #=smaller wire diameter, you will be okay. Now, as always, there are exceptions to this rule, but for our purposes, when working with copper electrical wiring, you will be okay with that rule because the majority of household wiring follows this rule.

If you need to know the diameter of a certain gauge, there are several tables you can look at on the internet. Wikipedia has a nice table. You can also use a calculator to determine the diameter of wire.

Color Coding on Electrical Wiring

Color coding for wiring is very important so that everyone knows what a ground wire is and what a live wire is. The only two items that are color mandated in the United States are the neutral and ground wires. Neutral wiring is either white or gray. Note: some call the white silver. In the United States, the standard is green, bare copper, or green and yellow striped for ground. Any other color wiring is for the phases wire (the wire that conducts electricity).

Accessories – Different Terminals and Connectors

There is a wide variety of terminals and connectors on the market today for joining wires. What many people do not know is that when choosing a connector, you must know what sizes of wire the connector will fit. Unfortunately, unlike the physical wires, there is no set standard with coloring. For instance, the table below shows the different colors and what each color means for the wire connectors we carry at CableTiesPlus. These sizes are for copper-to-copper wiring only.

AWG Color Coding



No. 22 to 14 AWG

Min. 2 No. 22 Str

Max. 3 No. 16300V

.64 mm DIA to 1.63 mm DIA

Min. .65 mm2

Max. 3.93 mm2*1,000V maximum in fixtures and signs.


Color Wire Combination Range(Inches) Wire Combination Range(mm) Gray 300VNo. 22 to 16 AWGMin. 2 No. 22 StrMax. 2 No. 16 300 V.64 mm DIA to 1.29 mm DIAMin. .65 mm2Max. 2.62 mm2 Orange 600V*No. 22 to 14 AWGMin. 1 No. 18 & 1 No. 20Max. 4 No. 16 & 1 No. 20 600V.64 mm DIA to 1.63 mm DIAMin. 1.34 mm2Max. 5.76 mm2 Yellow 600V*No. 18 to 12 AWGMin. 2 No. 18Max. 4 No. 14 & 1 No. 18 600V1.02 mm DIA to 2.05 mm DIAMin. 1.64 mm2Max. 9.14 mm2 Red 600V*No. 18 to 10 AWGMin. 2 No. 14Max. 2 No. 10 & 2 No. 12 600V1.02 mm DIA to 2.59 mm DIAMin. 4.16 mm2Max. 17.14 mm2


When looking at wiring accessories, it is important to look at the details for the individual items to ensure you are getting the proper accessory for the wiring you are using.

We hope you enjoyed learning a little bit more about wiring and how sizes are determined. A little side note. The size rule, higher gauge=smaller diameter, also works when you are working with sterling silver or gold wire for jewelry.

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