12 AWG wire is one of the most commonly used wire sizes in electrical engineering. With 25A ampacity at an average 75°C, this is the best wire to use for 20 amp services (of course, you have to account for the 80% NEC requirement, as we’ll explain later) .

We are going to systematically cover the basic characteristics of a 12 AWG copper wire and the opposite of this wire:

- Shorter 14 AWG wire (12 vs 14 AWG wire comparison).
- Larger 12 AWG wire (12 vs. 10 AWG wire comparison).

We’re going to look at 12 AWG wire:

- Diameter (mm). In other words. 12 gauge wire in mm.
- area or crosssection (mm2). In other words. 12 AWG to mm2.
- Number of turns of wire per inch and per cm.
- 12 AWG per meter and resistance per foot (ohms).
- Maximum current density per mm2.
- 12 AWG wire amp ratings: Ampacity at 60°C, 75°C and 90°C.
- 12 AWG wire wattage. In other words. How much power can 12 AWG wires conduct?

Let’s start with the diameter:

## 12 AWG wire diameter (12 gauge wire in mm)

The diameter or thickness of any given wire depends on the number and cross-section of the individual wires that make up the entire wire. In the case of a 12 AWG wire diameter, we’re going to look at a solid wire (stranded wire – with plastic insulation – is thicker).

12 gauge wire **2.053 mm thick**, This is equal to 0.0808 inches. Since the diameter of 12 AWG wire is so close to 2 millimeters, we also call it ‘2mm wire’.

If you compare the diameter of 12 AWG wire versus the diameter of 14 AWG wire, you can see that 14 AWG has a diameter of 1.628 mm. This means that the diameter of 14 AWG wire is about 21% smaller than the diameter of 12 AWG wire.

Compared to the larger 10 AWG wire with a diameter of 2.588 mm, the diameter of 12 AWG wire is 26% smaller.

## Cross-section: 12 AWG to mm2

12 gauge wire area or cross-section also depends on the number and cross-section of individual wires.

If you express the cross-section of 12 AWG in mm2, you can see that the area of 12 AWG is **3.31 mm2**, These are square millimeters; One unit for the surface.

in America, KCMIL Units Also used for circular shapes. kcmil stands for kilo-circular mills. 1 kcmil is roughly equal to half a mm2 (0.5067 mm2, to be exact). The area of a 12 gauge wire is 6.53 kcm.

Let’s compare the cross-sections of 12 vs 14 AWG wires and 12 vs 10 AWG wires:

Compared to the smaller 14 AWG wire with 2.08 mm2 cross-section, 12 AWG wire is 37% larger than 14 AWG wire in area.

Compared to the larger 10 AWH wire with 5.26 mm2 cross-section, 12 AWG wire is 59% smaller than 10 AWG wire in area.

### Number of 12 AWG Wire Turns

All AWG wires are made up of small individual wires. These small wires are spiraled throughout the wire or cable. For some applications, it is useful to know how many spirals are in 12 AWG wire.

12 gauge wire has 12.4 turns per inch of wire, and 4.87 turns per cm (centimeter) of wire.

### 12 AWG Wire Resistance (Ohms)

With each wire, you need to take resistance into account. Electrical resistance is measured in ohms (Ω).

The resistance of 12 AWG copper wire is **5.211 million per meter** (m / m). This translates to 1.588 million per foot (mΩ/ft).

As far as resistance is concerned, copper wires are about 40% more efficient for transporting electricity than aluminum wires.

Therefore copper wires of the same size have more amperes than aluminum wires. On top of that, with less resistance, 12 AWG copper wire is more resistant to heat generation than 12 AWG aluminum wire.

#### Current Density of 12 Gauge Wire

Current density is a measure of how much current a wire can carry per mm2 of cross-section. The current density is usually measured at 4A/mm2 of current.

The maximum current density a 12 AWG wire can achieve is 13.2 amps per mm2 (13.2 A/mm2).

## 12 AWG Amps: Amp Rating or Ampacity

How many amps can a 12 AWG wire handle? This is usually one of the most important specifications for any chord.

Can take 12 gauge wire:

- 20 amperes (20A ampacity or amperage) at 60 °C.
**25 amperes at 75 °C (25 A ampacity or amperage).**- 30 amps (30A ampacity or amperage) at 90°C.

When shaping a wire, we usually take the mean 75°C ampacity. This means that 12 AWG wire has an ampacity of 25A.

*Does this mean that 12 gauge wire can handle 25 amps?*

Yes and no.

12 AWG wire can handle 25 amps of current but we use this wire as 20 amp wire (more about that here). This is because we have to account for 80% of the National Electric Code (NEC) requirement.

This requirement states that any wire used in a circuit must carry a maximum of 80% of the total amperage. In the case of a 25A 12 AWG wire, this counts for a 20 amp circuit.

Therefore 12 gauge wire is used a. is done as **20 amp wire size**,

### 12 AWG vs 14 AWG vs 10 AWG Amp Rating

Let’s compare the average amperage of 12 AWG wire versus the smaller 14 AWG wire and the larger 10 AWG wire. Here is the average ampacity rating for all these wires:

- 10 AWG wire has 35A ampacity (accounting for the 80% NEC requirement, this is a 28 amp wire size).
- 12 AWG wire has 25A ampacity (accounting for the 80% NEC requirement, this is a 20 amp wire size).
- 14 AWG wire has 20A ampacity (accounting for 80% of the NEC requirement, this is a 16 amp wire size).

As you can see from this list, 12 AWG wire has 29% less ampacity than 10 AWG wire. If you check the amp rating for 12 vs 14 AWG wire, 12 AWG wire has 25% more ampacity than 14 AWG wire.

Overall, we hope that you now have a better understanding of the 14 AWG wire specifications. You can find the full AWG wire chart with mm, mm2 and median ampacities here.

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