6 Gauge Wire Vs 8 Gauge Wire: mm, mm2, Amps Comparison

Here is a question that we get quite often: Which is thicker 6 gauge or 8 gauge wire? To address this very easy question, we have created a full 6 gauge wire vs 8 gauge wire comparison in terms of diameter (mm), cross-section (mm2), and ampacity (amps wire can handle).

First of all, let’s clearly answer the question of which wire is bigger – 6 AWG or 8 AWG. Here is the screenshot from the AWG wire size chart for copper wires:

6 Gauge Wire Vs 8 Gauge conductor

As you can see, 6 AWG wire is bigger than 8 AWG wire. In the AWG wire size scale, the smaller the AWG number, the thicker the wire.

Let’s compare the main characteristics of these two wires:

6 AWG Wire Vs 8 AWG Wire Comparison

Wire Characteristic: 6 Gauge Wire 8 Gauge Wire
Diameter (in inches) 0.1620 inches 0.1285 inches
Diameter (in millimeters) 4.115 mm 3.264 mm
Cross-section (in mm2) 13.3 mm2 8.37 mm2
Ampacity at 60°C (140°F) 55 Amps 40 Amps
Ampacity at 75°C (167°F) 65 Amps 50 Amps
Ampacity at 90°C (194°F) 75 Amps 55 Amps

The difference between 6 AWG and 8 AWG derives from a single fact: 6 AWG is thicker than 8 AWG. All the following differences in characteristics between 6 gauge wire and 8 gauge wire are the result of this:

  • Diameter: 6 gauge wire is 26.1% thicker than 8 gauge wire.
  • Cross-section: 6 gauge wire has a 58.9% larger cross-section than an 8 gauge wire.
  • Ampacity at median 75°C (167°F) temperature: 6 gauge wire can handle 15 more amps than 8 gauge wire. Basically, 6 AWG wire has a 30% higher ampacity than 8 AWG wire.

This is the basic understanding you need to have when considering which wire to choose; 6 AWG or 8 AWG. If you have any questions regarding this comparison, you can use the comments below and we’ll help you out.

2 thoughts on “6 Gauge Wire Vs 8 Gauge Wire: mm, mm2, Amps Comparison”

  1. I have a Westinghouse generator with a 50 amp cord that plugs into a 50amp inlet box. The inlet box which is outside is less than 3 feet from the service panel inside the house. The electrician used 8 gauge wire for the 50 amp circuit. Should he have installed it with 6 gauge wire?
    Thanks,
    Dan

    Reply
    • Hi Dan, according to NEC, the 8 gauge wire has 50 amp ampacity. However, to have a bit of safety margin, it would be better to use 6 gauge wire since it has 65A ampacity. Hope this helps.

      Reply

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