How Thick is 12 Gauge Wire?

A wire gauge is the measurement of the diameter of electrical wires. A 12 gauge wire is the medium choice wire for carrying current. The 12-gauge wires can sustain up to 20 amps of current. Excess current supply to the wire will make it unusable.

In this guide, we will go into more detail on how thick a 12 gauge wire is and its characteristics.

Where can I use a 12 gauge wire? It is used in the kitchen, bathrooms, and outdoor receptacles. A 120-volt air conditioner that supports 20 amps can also use a 12 gauge wire.

The diameter of 12 gauge wires is 2.05 mm or 0.1040 inches according to the SWG metric system. They have a low resistance to the current flow and can handle up to 20 amps.

What is a 12 Gauge Wire?

As aforementioned, the thickness of 12 gauge wires is 2.05 mm (0.1040 inches) as per the SWG metric system. Their resistance is too low which makes them convenient wires for conveying electrical current.

They are used in the kitchenette, outdoor receptacles, washrooms, and in 120-volt air conditioners (20 amps). Typically, many thinner wires can be put together than thicker wires.

12 gauge wires are efficient power transmitters, especially where a large power supply is required. I, therefore, recommend the use of 12 gauge wires to enhance power transmission.

In essence, the wire quality does not considerably relate to the wire size. However, with a 12 gauge wire (small gauge), you can get more conducting electrical wires. Their resistance is also small, usually less than 5% of the total resistance. You can lose only 1.588 ohms in 1000 feet of a 12 gauge copper wire. You may also run a 12 gauge flexible wire with a speaker of 4.000 ohms. I also recommend using 12 gauge copper wire over 12 gauge aluminum. Aluminum wires are stiffer and have less conductivity.

Amps Rating of 12 Gauge Wires

different sizes of wire with their amps

The maximum amount of amps a 12 gauge wire can handle is 20 amps. And the 20 amps can be ferried to 400 feet in a 12 gauge copper wire – insulated. If the wire stretches beyond 400 feet, voltage loss begins to occur. Increasing the voltage solves the problem. A higher gauge wire can transport current to greater distances than smaller gauge wires.

Practically, the 12 gauge wires, though rated at 20 amps, can handle up to 25 amps. However, note that higher values of amps can fry your wires and circuit breaker. It is worth noting that the higher the heat rating, the higher the amps.  In that sense, aluminum wires have lower conductivity when compared to copper wires; hence they will carry lower amps relative to copper wires – as the heat rating increases. (1)

The Thickness of a 12 Gauge Wire

14 gauge versus 12 gauge wire

As mentioned earlier, the thickness of 12 gauge wires is 2.05 mm (diameter). The gauge and thickness of a wire have a relationship. Thinner gauges have higher resistance to current flow.  Since voltage varies indirectly with current, a decrease in current in thinner gauge wires) cause a corresponding increase in voltage potential across the wire. The exact explanation for this deviation is that thinner wires have less electron charge density. The electrons are the mediums of electrical conductivity. Thicker wires have a higher electron charge density. (2)

Take a look at some of our related articles below.

(1) aluminum wires have lower conductivity –
(2) electron –

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About Sam Orlovsky

b1d87d2ee85af3e51479df87928bdc88?s=90&d=mm&r=gCertifications: B.E.E.
Education: University Of Denver - Electric Engineering
Lives In: Denver Colorado

Electrical engineering is my passion, and I’ve been in the industry for over 20 years. This gives me a unique ability to give you expert home improvement and DIY recommendations. I’m not only an electrician, but I also like machinery and anything to do with carpentry. One of my career paths started as a general handyman, so I also have a lot of experience with home improvement I love to share.

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