WIRE GAUGE CHARTS
8 wire in mm
Thickness: 3.26 mm diameter (0.128 inches), 8.37 mm² cross-section of solid copper.
Specifications
- Diameter
- 3.26 mm
- Diameter (imperial)
- 0.128 in
- Cross-section
- 8.37 mm²
- Area (kcmil)
- 16.5
- Copper resistance
- 0.628 Ω/1000 ft
- Copper resistance (metric)
- 2.06 Ω/km
- Copper weight
- 75.0 g/m
- Ampacity (NEC 75 °C)
- 50 A
Nearest metric sizes
8.37 mm² does not match a standard metric cable size exactly. The closest conventional cross-sections are4 mm², 6 mm² and 10 mm²— engineers round this wire up (larger cross-section) for ampacity, or accept the raw equality for signal work.
One gauge away:9 · thinner7 · thickerFull chart →
Frequently asked questions
Is 8 gauge wire thick or thin?
8 gauge wire is 3.26 mm in diameter. On the AWG scale a lower number means a thicker wire, so 8 AWG sits in the mid-power range used for appliances and small feeders.
How many amps can 8 gauge wire carry?
NEC Table 310.16 rates 8 AWG copper at 50 A in the 75 °C column (see our amp chart for 60/75/90 °C ratings). Use the calculator to check voltage drop at your run length; long runs often force one size thicker.
What diameter is 8 wire in millimeters?
8 gauge wire is 3.26 mm (0.128 in) in diameter, with a solid-conductor cross-section of 8.37 mm².