You cannot determine whether or not 6/3 cables are appropriate for your application without first identifying the amp rating associated with this wire size.
How Many Amps 6/3 Wire Carry?
6/3 wire can carry 55 amps of electricity. But the amp rating of a 6/3 cable will vary depending on the temperature. For instance, the conductors withstand 55 amps at 60 degrees C. But at 75 degrees C, that figure rises to 65 amps. At a temperature of 90 degrees C, 6/3 cabling can transmit as much as 75 amps.
To be more specific, this wire size accommodates 55A breakers. However, the market doesn’t offer 55-amp breakers. Therefore, you have to round up to 60amps. That sounds dangerous, but those five extra amps are not a problem for this gauge. It can handle the current with relative ease.
Laypeople do not expect the temperature to make a difference. However, you have to remember the reason why the wire size matters. The goal of selecting the appropriate gauge is to prevent fires.
A wire that has to carry more current than its rating allows will overheat and melt. That is the worst possible outcome. Even if the wire survives, it can destroy your equipment, not to mention electrocuting the inhabitants of your home.
This is why the ambient temperature matters. A conductor is more likely to overheat if the ambient temperature is already too high. The variable encourages contractors to consider the location before selecting a wire size.
They know that wires below ground or inside the walls don’t have proper ventilation. As such, they have to select conductors with higher temperature ratings that can withstand the heat.
Wires with higher temperature ratings tend to carry more electricity. For that reason, the amp ratings of different wire sizes will also reveal the temperature rating.
What does this mean? 6/3 is not the largest wire size on the market. However, you can use 6/3 cables to accommodate applications whose electrical requirements exceed 55 or even 60 amps if you target the correct temperature rating.
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What Does NEC Say About It?
6/3 Wire Amp Rating
| 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 |
| 6AWG | 55 | 65 | 75 | 40 | 50 | 55 |
According to NEC, 6AWG conductors have an amp rating of 55A. The table also includes the amp ratings of 6AWG wires at different temperature ratings.
It looks like the gauge has an amperage ranging from 40 to 75 amps, at least according to the National Electric Code. Ultimately, you don’t have to listen to the NEC.
Your local code is the priority. Find out if the local authorities in your area have published any guidelines regarding wire sizes and their amp ratings. If their tables contradict those of the NEC, you should listen to the local code.
Where the practical applications are concerned, everyone agrees that 55 amps are appropriate for 6/3. You should proceed with this information in mind.
Does Distance Affect Its amps?
The distance will affect the amperage because it shapes the voltage drop. Any current you transmit through a wire to a device at the other end will encounter resistance. The resistance will reduce the power reaching the device. If the voltage drop is high enough, the appliance may stop working altogether.
Some items fall apart because they have to work twice as hard to pull the electricity they need, burning out their motors in the process.
50A wire sending electricity to an object 100 feet away will record a voltage drop of 20 percent. To compensate for that voltage drop, you have to increase the amps by the same amount, which equates to roughly 75A once you take the NEC’s 80 percent rule into account.
A wider cable will transmit more electricity because it has less resistance. If you increase the distance while maintaining the same wire size, the resistance will generate more heat than the conductors can handle. You run the risk of starting a fire.
For that reason, laypeople with complex wiring projects are often encouraged to consult professionals. You need an experienced electrician on your team that can calculate the voltage drop before recommending a wire size.
How Far Can You Run 6/3 Gauge Wire?
You can run a 6 gauge wire to maximum distance of 76 feet with 120v, 153 feet with 240v, and 306 feet with 480v.
| Volt with 55 Amps | Maximum Distance (Copper) |
| 120 | 76 feet |
| 240 | 153 feet |
| 480 | 306 feet |
Let’s check the distance for the 6 gauge wire with 3 phase line
| Volt with 55 Amps | Maximum Distance (Copper) |
| 120 | 88 feet |
| 240 | 177 feet |
| 480 | 354 feet |
With electrical cables, you have to limit the distance. A shorter wire has less resistance than a longer one. But you cannot avoid long lines in a home. When selecting the length, you must limit the voltage drop to 3 percent.
This is the threshold the NEC expects contractors to target. Therefore, with that 3 percent goal in mind, you should limit 6AWG cables to 76 feet for 120V circuits and 153 feet for 240V circuits.
If you want to cover a longer distance, get a thicker cable. Jump up to 4AWG. This allows you to increase the length without dramatically raising the voltage drop.
Does Material Affect Its Amp Rating? 6 3 Wire Aluminum VS Copper Amp Rating
6/3 copper wire carries 55 amps at 60 degrees C, 65 amps at 75 degrees C, and 75 amps at 90 degrees C. 6/3 AWG aluminum cable can carry 40 amps at 60 degrees C, 50 amps at 75 degrees C, and 55 amps at 90 degrees C.
If you don’t understand why your 6/3 wiring cannot carry as much electricity as your neighbor’s 6/3 cable, you probably have aluminum instead of copper. Even though the size of the conductors is the same, copper’s conductivity is superior to that of aluminum.
It has a better current carrying capacity. As you can see, distance is just one small component of this equation. You can undersize an application’s wires even though you selected the correct gauge because you forgot to consider the material.
To be clear, you don’t have to use copper simply because it is more conductive. If you can’t afford copper, aluminum will do just fine if you get a higher gauge. Use 4AWG instead of 6AWG to compensate for the difference in conductivity.
What is 6-3 Wire Used For?
| Hot Tub | YES |
| Stove | YES |
| Electric Range | YES |
| Sub Panel | YES |
| Tesla Charger | YES |
You shouldn’t expect 6/3 wires to run these devices in every situation. The rating of the device matters. If a stove’s rating falls within the 55-75A range, it can work with this wire size.
Otherwise, you should get a thicker cable. 6/3 wires are formidable. Boasting a voltage rating of 600V and capable of withstanding temperatures ranging between -40 and +90 degrees C, it can handle the strain associated with running most household devices and appliances.
But you have to match the electrical draw of the appliance to the cable’s amperage and temperature rating. If your devices have a watt rating instead of an amperage, divide the wattage by your circuit’s voltage to get the amps. This will simplify the process of matching 6/3 wiring to the right task.
Can I Use 6-3 Wire Outdoors?
Feel free to use your 6/3 AWG wire outside. However, the size of the conductors has nothing to do with the line’s ability to survive outside. If the exterior conditions concern you, but you don’t have the money to buy armored cables, pull the 6/3 AWG wire through a conduit. 6/3 wires are compatible with ¾ conduits.
Your ability to use the cable inside or outside is unrelated to the wire size. Your biggest concern is the elements, which include scorching sunshine, freezing winters, rain, foot traffic, etc.
Outdoor cables tend to wear out at a faster rate because of all the punishment they take. This is why people use armored cables. They have an additional layer of protection that repels everything from heat to corrosive chemicals and even moisture.
6/3 Romex Wire Amps
6/3 Romex Wire can accommodate 55 amps. But 55A breakers don’t exist. Therefore, if you need a breaker that fits a 6/3 Romex Wire, aim for 60 amps. Rounding up is perfectly legal.
The NEC encourages consumers to use the next largest size when they encounter situations like the one above. Keep the temperature and material in mind. They will change the amperage.