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:
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 60ยฐC (140ยฐF) | 55 Amps | 40 Amps |
| Ampacity at 75ยฐC (167ยฐF) | 65 Amps | 50 Amps |
| Ampacity at 90ยฐC (194ยฐF) | 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 75ยฐC (167ยฐF) 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.
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
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.
I’m an EE, BS E with 40 years experience, retired now. I specialized in RF, Analog, and microwave circuit and system design. Also licensed Ham. My understanding of NEC is they require reduction of circuit ampacity to 80% unless the design is stamped by a licenced Engineer. The current maximum size for a 120V appliance circcuit with 20 Amp beaker. is 1800 W, 15A at 120V. 80% of 20 A is 16A, 1920W, allowing a little margin.