2/0 Gauge Wire Guide: Ampacity, Size Chart, and Practical Tips for Installers

2/0 gauge wire is one of those topics where almost everyone has an opinion, and a fair number of people are quietly guessing. In our daily conversations with electricians, panel builders, solar installers, and maintenance crews, the same questions come back again and again: is 2/0 the same as 2 AWG, how many amps can it really carry, and why does the same cable show up as 70 mm² on one drawing and 2/0 on another?

We have been manufacturing cable since 1988, so we have watched these questions change with each generation of equipment. What follows is our plain-language answer, with the dimensions, the ampacity figures, and the practical details that actually matter once the drum is on site and the pull is about to start.

What the "2/0" in 2/0 Gauge Wire Actually Means

AWG stands for American Wire Gauge, a sizing system that has been in use since the nineteenth century. It works in a way that feels backwards at first: for small conductors, the higher the number, the smaller the wire. That pattern holds down to size 1/0, and then it reverses. From there, more zeros mean a bigger conductor — 1/0, 2/0, 3/0, 4/0.

So 2/0 is a large conductor, not a small one, and it has nothing to do with size 2 AWG beyond a shared digit. Electricians usually say it as "two aught" or "double aught," and older drawings often write it simply as 00.

• Conductor diameter, solid equivalent: roughly 0.365 in or 9.27 mm
• Cross-sectional area: about 67.4 mm²
• Circular mil area: 133,100 cmil
• Compared with 2 AWG: approximately double the metal

The last point is worth remembering. Three steps on the AWG scale double the area, so 2 AWG, 1 AWG, 1/0, and 2/0 form a ladder where each rung adds real capacity. In metric markets, 2/0 is normally treated as the neighbour of 70 mm² — a close match, but not an exact one, which we will return to later.

2/0 Gauge vs 2 AWG: Side by Side

Confusing a 2 with a 2/0 is the most common and most expensive mistake we see, because the two look similar on a one-line diagram and behave very differently in service. The table below places the usual suspects next to each other.

Two patterns jump out. Copper 2/0 carries roughly fifty percent more current than copper 2 AWG at the same temperature rating, so the two are never interchangeable. Aluminium, meanwhile, needs a larger size for the same duty, which is why a 2/0 aluminium service conductor is usually compared with a 1/0 or 2 AWG copper one rather than with 2/0 copper.

Ampacity: What 2/0 Gauge Wire Can Really Carry

The figures above come from the familiar ampacity tables used across North America. Copper 2/0 settles at 175 A for a 75 °C rated conductor and around 195 A when the insulation and terminations are rated 90 °C. Those are starting points, not promises, and several factors pull them downward:

• Ambient temperature above 30 °C, which is routine in plant rooms, roof spaces, and desert installations
• More than three current-carrying conductors bundled in one raceway or tray
• Continuous loads, where the familiar 125 percent rule applies to the overcurrent device
• Termination limits, because many breakers and lugs are only listed for 75 °C even when the cable itself is rated higher

Voltage drop is the other half of the story. On a long feeder, the limiting factor is often the voltage available at the far end rather than the temperature of the insulation, and that is where a 2/0 run starts to look attractive even when a smaller conductor would pass the thermal check. If the arithmetic is new to you, our explainer on wire cross-sectional area walks through the relationship between AWG, mm², and conductor resistance step by step.

Where 2/0 Gauge Wire Earns Its Place

Feeders, sub-panels, and service equipment

On the AC side, 2/0 copper is a natural fit for sub-panel feeders, large rooftop units, and 200 A service work, especially where the run is long enough that voltage drop decides the size. A 0.6/1 kV XLPE or PVC insulated power cable in a 70 mm² metric equivalent is the product most installers reach for in these situations, and it is the size range we build every day.

XLPE/PVC Insulated 0.6/1 kV Power CableFor AC feeders and fixed distribution up to 0.6/1 kV, including 70 mm² equivalents; fire-resistant armored variants available for indoor, tunnel, trench, or direct-burial routes.View Product →

Battery, inverter, and charging circuits

On the DC side, 2/0 shows up in short, high-current links: battery banks, inverters, chargers, and the heavy jumpers between them. Here the stranding matters as much as the size. A fine-stranded flexible conductor bends around terminals without fatigue, while a stiff 19-strand building wire will fight you in a tight enclosure and may eventually crack at a lug. Electric vehicle charging is a good example of an application where both the current and the flexing are real, so dedicated EV charging cable is usually the better answer than general-purpose building wire.

EV Charging Cable 450/750 V for Charging StationsFlexible thermoplastic elastomer charging cable with optional signal cores and shielding suited to new energy vehicle charging and dedicated charging-station connections up to 450/750 V.View Product →

Welding leads, cranes, and heavy equipment

Welding cable and equipment leads in this size are judged by flexibility and abrasion resistance rather than by building-code ampacity tables. The rubber or elastomer jacket does the heavy lifting, and the conductor is usually far more finely stranded than the same gauge in a tray.

Copper or Aluminium 2/0?

Both work, and the choice is usually economic rather than technical. Copper 2/0 conducts better, terminates more forgivingly, and takes up less space for the same current. Aluminium 2/0 is lighter and cheaper, which matters on long overhead runs and large service entrances, but it asks more of the installer.

• Use terminals and lugs listed for aluminium, and apply the correct jointing compound
• Clean and brush the conductor before terminating, and re-check torque after the first thermal cycle
• Avoid mixing metals without a bimetallic connector rated for the purpose
• Remember that aluminium expands and contracts more, so poor terminations loosen over time

Done properly, aluminium 2/0 gives decades of service. Done casually, it is one of the more common causes of hot joints we are asked to investigate.

Stranding, Insulation, and Installation Environment

Gauge is only one of three decisions. The second is stranding: compact and stranded class 2 conductors for fixed wiring, flexible class 5 conductors where the cable will move, vibrate, or be handled. The third is insulation and jacket, and this is where projects are won or lost.

PVC insulation is comfortable at 70 to 75 °C and suits most indoor distribution work. XLPE pushes the rating to 90 °C, tolerates higher fault currents, and is the standard choice for anything above low voltage. Add the environment on top: direct burial, permanently wet ducts, sunlight exposure, oil mist, or rodent pressure all change the jacket specification rather than the conductor size.

Where a 2/0 run ends up buried, in a wet duct, or in a wash-down area, the conductor is the easy part — the sheath is the part that decides how long the circuit lasts. Our waterproof series cables were developed for exactly those conditions.

Waterproof Series Cables for Wet and Buried InstallationsRadial and longitudinal waterproof cable options from 300/300 V to 26/35 kV, including power, control, and measuring types for wet, underwater, or buried routes.View Product →

When 2/0 Becomes 70 mm²

International projects almost always end up working in metric sizes, and IEC 60228 is the reference point. Because 2/0 AWG equals about 67.4 mm², the metric neighbour is 70 mm², and in most cases a 70 mm² conductor will satisfy a 2/0 requirement on resistance and ampacity.

Do not assume it fits, though. Overall diameter changes with stranding, insulation thickness, and sheath design, and those dimensions drive gland sizes, lug barrels, bending radii, and tray fill. If a project mixes AWG and metric drawings, compare conductor resistance and finished diameter, not just the headline number.

Our own catalogue runs from 0.6/1 kV XLPE and PVC power cable through 6–35 kV and 66–500 kV XLPE cable, alongside bare wire and aerial insulated conductors, equipment and control cables, and the special range covering fire-resistant, high-temperature, photovoltaic, and EV charging products.

A Short Checklist Before You Order

1. Confirm the size in mm² as well as AWG, and check conductor resistance rather than diameter alone.
2. Check the termination temperature rating, because the lowest rating in the circuit governs.
3. Decide copper or aluminium early, since it affects lugs, glands, and space.
4. Match stranding to movement: fixed runs, flexible runs, and vibration are different jobs.
5. Confirm jacket and insulation against the real environment, not the drawing room.
6. Ask for conductor resistance data and routine test reports with the delivery documents.

We Are Happy to Check Your Sizing

Cable sizing questions are usually quick to answer and expensive to get wrong, so we never mind being asked. We have been producing wire and cable in Jiangsu since 1988, working from raw material intake through to final dispatch under a quality system that covers every stage in between, and we supply projects at home and abroad.

If you are weighing a 2/0 copper feeder against a 70 mm² metric equivalent, or you simply want a second opinion on stranding and sheath for a wet or high-temperature route, send us the drawing and the environment. We will tell you honestly which of our products fits, and which one does not.