2/0 is a rare wire size. Engineers use it all the time. However, laypeople rarely interact with it because most of the appliances in a residential setting use 12 to 14-gauge wiring. This is what you should know about the wire size:
2/0 Gauge Wire Amp Rating
How Many Amps Does 2/0 Gauge Wire Carry?
| Copper | Aluminum | |||||
| Wire Gauge Size | 60˚C NM-B, UF-B | 75˚C THW, THWN, SE, USE, XHHW | 90˚C THWN-2, THHN, XHHW-2, USE-2 | 60˚C TW, UF | 75˚C THW, THWN, SE, USE, XHHW | 90˚C XHHW-2, THHN, THWN-2 |
| 2/0AWG | 145 | 175 | 195 | 115 | 135 | 150 |
2/0 can transmit 145 amps at 60 degrees, 175 amps at 75 degrees, and 195 amps at 90 degrees.
Interestingly, 2/0AWG conductors are routinely used for 150A applications even though 1/0 has an ampacity of 150A at 75 degrees C.
What Is 2/0 Gauge Wire?
2/0 is a wire size. You see it in AWG wire size charts. Contractors in many European and Asian countries have never even heard of this size because they use mm2 to measure a wire’s thickness.
This paper in the Journal of Instrumentation Technology and Innovations mentions the steps The International Electro-Technical Commission (IEC) has taken to harmonize wiring standards on the international stage. However, their efforts have done little to dissuade people from using AWG.
The American Wire Gauge is a popular unit of measurement. Despite its name, many countries outside the United States have adopted AWG because of its convenience and simplicity. The wire sizes range from 0 to 44.
In the AWG, the thinnest wires have the largest number. On the other hand, the smallest numbers go hand in hand with the thickest conductors. But if the wire sizes range between 0 and 44, where does 2/0 fall?
0 is not the thickest wire in the AWG. You have a few additional sizes above 0, namely ‘00,’ ‘000,’ and ‘0000.’ Engineers use the term ‘aught’ to refer to these wire sizes.
For instance, 2/0 is ‘2/0 aught.’ Some contractors remove the sash (/) altogether. Instead, they call this wire size ‘2 0.’ Whether the jacket says ‘2 0’ or ‘2/0,’ the wire’s gauge doesn’t change.
Is 2/0 Gauge Wire The Same As 2 Gauge Wiring?
These two sizes are not the same. 2/0 is thicker than 0. It has a diameter of 0.3648 inches (9.266mm) and a cross-section of 67.4 mm2.
2 gauge wiring is thinner than 0. It has a diameter of 0.2576 inches (6.544 mm) and a cross-section of 33.6 mm2.
Precluding exceptional circumstances and emergencies, you can’t substitute 2/0 with 2AWG. The difference in thickness is too significant to ignore.
Why do You need To Know 2/0 Gauge Wire Amps?
This paper from Obinna E. Igwe (University of Kentucky) highlights the importance of accurately calculating ampacity values while configuring power distribution systems. The ampacity allows you to determine whether a particular wire size fits your application.
Connecting an application to the wrong gauge will start a fire. This is because electrical lines naturally oppose the flow of electricity. Exposing those lines to more current than they can handle increases that opposition, which, in turn, leads to overheating.
Even though electrical wires are metallic, they can still melt if the temperatures are high enough. Admittedly, 2/0 is one of the safest sizes in the world. You can trust the gauge to run the heaviest appliances without overheating. That includes power tools.
In the case of 2/0 wiring, it is a question of cost-effectiveness and ease of installation. Keep the following in mind:
- The thicker the wire, the higher the price tag. 2/0 is one of the highest gauges on the wire size chart. Therefore, it is also one of the most expensive. You don’t want to waste money on this gauge when you don’t need it. For instance, it wouldn’t make sense to wire a bedroom circuit with 2/0AWG. You don’t need 67.4 mm2 wiring to operate a few lights and TVs.
- The thickest wires are also the stiffest and heaviest. In other words, 2/0AWG is more difficult to install than 12AWG or even 2AWG. The situation becomes more challenging if the application in question requires you to pull the electrical line through a conduit.
Using the correct wire size for each application can save a lot of time and money. Keep in mind that contractors charge by the hour. The more time they spend installing 2/0 wiring in your home, the more money you will pay.
Therefore, you should calculate your application’s electrical needs before you buy the wiring. Try to match the gauge to the application’s amps. There’s no point in buying 2/0 lines when 10 to 14-gauge wires can run most household appliances.
Uses of 2/0 Gauge Wire
2/0AWG can handle the heaviest applications on the market. 2/0 is a suitable size for batteries. The cables, which have stranded copper conductors, can sustain 600 volts and accommodate 200A applications at 15 feet.
The size is just as common in the welding industry. You can’t afford to use the wrong gauge for welding. You need a cable long enough to reach your workstation but also thick enough to compensate for the considerable resistance.
2/0 ticks the right boxes. Additionally, the wire size appears in RVs, inverters, and solar panels.
Does The Material (Copper/Aluminum) Affect 2/0 Gauge Wire Amps?
Yes, it does. Each wire size chart shows different amps for copper and aluminum. Why? Because copper is more conductive. The material has a higher current-carrying capacity than aluminum, which is why so many wires on the market are copper.
This should discourage you from replacing copper wires with aluminum lines of the same gauge. You can only replicate a copper wire’s performance by finding an aluminum conductor with a higher gauge.
You can see that 2/0 copper wire carries a maximum of 195 amps. But that figure falls to 150A for 2/0 aluminum. Therefore, you are better off replacing 2/0 copper with 3/0 aluminum.
While 2/0 aluminum can replace 2/0 copper in some instances, the practice is risky. A surge is more likely to overwhelm the wires.
Does The Insulation Rating Affect 2/0 Gauge Wire Amps?
Technically, the insulation is concerned with the voltage. However, wires have an insulation rating that influences the temperature range. The temperature rating changes the ampacity because the ampacity determines the amount of electricity a wire can transmit without overheating.
The more current flowing through a conductor, the more heat the wire generates. This is why overloading a wire is so dangerous. The conductor will overheat, melting the insulation. Manufacturers have solved this problem by making cables with higher temperature ratings.
They can transmit more power at a higher temperature without overheating. In the case of a 2/0 gauge wire, it transmits 175 amps at 75 degrees C and 195 amps at 90 degrees C.
You must take both the material and temperature rating into account when selecting a suitable wire size. Even when you increase the temperature rating, 2/0 aluminum will carry fewer amps than 2/0 copper.
Does The Distance Affect 2/0 Gauge Wire Amps?
For Copper Wire,
Single Phase
| Voltage | Amp | Voltage Drop | Max Distance |
| 120 | 145 | 3% | 147 ft |
| 240 | 145 | 3% | 295 ft |
| 480 | 145 | 3% | 590 ft |
Three Phase
| Voltage | Amp | Voltage Drop | Distance |
| 120 | 145 | 3% | 170 ft |
| 240 | 145 | 3% | 340 ft |
| 480 | 145 | 3% | 681 ft |
The distance affects the length. Shorter distances require shorter wires. These are the safest because the shortest lines have the least resistance. Longer distances call for longer wires. And unfortunately, the resistance will increase with the wire length.
Once again, 2/0 is safer than most wire sizes because you typically prevent overheating in long wires by increasing the gauge. 2/0 gauge wiring is thick enough to transmit large volumes of current over long distances without overheating.
Nonetheless, you should apply caution by minimizing the length.
Shorter lines are safer. Look at the cords powering your heavy-duty appliances. They are short for a reason. Don’t be afraid to upgrade to 3/0 copper if you want to cross larger distances while operating applications that exceed 200 amps.