2 gauge wire measures 6.54 mm across. Its cross-section is 33.6 mm², or 66,360 circular mils.
This gauge is unusual, and it is worth knowing why before you specify anything.
Table of Contents
The gauge that actually lines up
Convert almost any AWG size and you land between two metric sizes with an awkward gap either side. 12 AWG converts to 3.31 mm² and the nearest size up is 4 mm², 21% more copper. 22 AWG converts to 0.324 mm² and the nearest size up is 54% larger.
2 AWG is different. It converts to 33.6 mm², and the metric size above it is 35 mm² — only 4% more.
That 4% has a consequence most conversion tables miss. Cable is verified by conductor resistance, not by measuring copper. A 2 AWG conductor runs about 0.51 Ω/km. The limit for 35 mm² is 0.524 Ω/km.
2 AWG passes. It is one of only two gauges in the entire range that meets the resistance requirement of the metric size it rounds up to. The other is 2/0.
Every other gauge fails. 12 AWG misses the 4 mm² limit by 13%. 6 AWG misses 16 mm² by 13%. 22 AWG misses 0.5 mm² by 48%. Only where the round-up is tiny does the conductor stay inside the limit — the mechanism is explained in why AWG doesn’t match metric sizes.
What that means in practice
For most gauges, “AWG size equals metric size” is a claim that falls apart at a factory acceptance test. For 2 AWG and 35 mm² it holds up on the number that matters.
That does not make them identical. 35 mm² still has 4% more copper, the stranding will differ, and the product standards for the two cables are not the same. But if a spec calls for 35 mm² conductor resistance and you have 2 AWG in front of you, it will pass the test.
Going the other way is where it gets expensive. Round down to 25 mm² and you lose 26% of the cross-section — one of the larger drops in the range. 25 mm² has a resistance limit of 0.727 Ω/km against 2 AWG’s actual 0.51. That is a real downgrade on a feeder.
Diameter is not the same as conductor size
The 6.54 mm figure is solid wire. Nobody installs solid 2 AWG — at this size the cable is stranded, and stranding makes it fatter.
At 35 mm², the maximum conductor diameters are:
| Construction | Max diameter | Min strands |
|---|---|---|
| Class 1, solid | 6.7 mm | 1 |
| Class 2, stranded | 7.9 mm | 7 |
| Class 5, flexible | 9.2 mm | — |
Class 5 is 41% wider than the solid figure. Size a gland, a compression lug, or a conduit off 6.54 mm and take delivery of flexible cable, and nothing fits. See conductor classes 1, 2, 5 and 6 for what separates them.
This is the single most common mistake at feeder sizes. The conversion gives you a number, the number looks like a diameter, and it is a diameter — of a conductor nobody sells in that construction.
Where 2 AWG is used
Service entrance conductors, sub-panel feeders, large motor circuits, and grounding electrode conductors on bigger services. It is a distribution gauge, not a branch circuit gauge.
At this size the two things that decide the conductor are ampacity and voltage drop, and both depend on the installation. Insulation temperature rating, ambient temperature, installation method, and conductor grouping all change the answer. Run the calculation for your actual installation rather than reading a single number off a table.
FAQ
What is 2 AWG in mm? 6.54 mm in diameter as solid wire, which is 257.6 mils. Stranded 2 AWG is wider — expect up to 7.9 mm for standard stranding and 9.2 mm for flexible.
What is 2 AWG in mm²? 33.6 mm². The metric cable size that replaces it is 35 mm², which is 4% larger.
Is 2 AWG the same as 35 mm²? Closer than any other pairing. 35 mm² has 4% more copper, but a 2 AWG conductor does meet the 35 mm² resistance limit, which is not true for almost any other gauge. For most practical purposes they are interchangeable — check the product standard for the specific cable type before committing.
Can I use 25 mm² instead of 2 AWG? It is 26% less copper. On a feeder that is a meaningful reduction in ampacity and a meaningful increase in voltage drop. Only if the circuit calculation supports it.
Why do most gauges not line up like this? Because the two systems were designed independently. AWG steps by a fixed geometric ratio; the metric series was chosen as round numbers. They cross at 2 AWG and 2/0 by coincidence, not by design. See how the AWG system works.
Is 2 AWG bigger than 2/0? No. 2/0 is thicker. The 0-series continues past 1 AWG in the direction of larger conductors — 1/0, 2/0, 3/0, 4/0 — so 2/0 has roughly double the copper of 2 AWG.
Reference
| Property | 2 AWG |
|---|---|
| Diameter, solid | 6.54 mm |
| Diameter, solid | 257.6 mils / 0.2576 in |
| Cross-sectional area | 33.6 mm² |
| Area | 66,360 cmil |
| Resistance, solid copper at 20 °C | 0.51 Ω/km |
| Metric size to order | 35 mm² (+4%) |
| Metric size below | 25 mm² (−26%) |
| Meets the 35 mm² resistance limit | Yes |
Convert any other gauge with the AWG to mm² converter, or work the other direction from 35 mm² to AWG.