By Erik Watkins

6/3 Romex, Nm-b, Aluminum Wire Amp Rating & Its Usages

Last updated: May 18, 2023
6/3 Romex, Nm-b, Aluminum Wire Amp Rating & Its Usages

The 6/3 cable is universal and utilized for practically every application, including lighting, wiring of devices, and mechanical circuits. Still, you must understand the 6/3 wire amp rating if you want to use this cable. 

That is because without first determining the amp rating attached to this wire size, you cannot establish whether or not 6/3 cables are suitable for your application.

You can get help from our article. We’ll give you a quick truth and other pertinent information you might be interested in.

How Much Is The Amp Rating For The 6/3 Wire?

6/3 wire can carry electrical current at 55 amperes, be it 6/3 romex or NM-B amp rating. 

Yet, 55A breakers are nonexistent. To accommodate this type of wire, use a breaker that has 60 amps. You can round up this figure because it’s completely acceptable and legal. 

The current carrying capacity is also impacted when the temperature rating varies.

In particular, the current handling for 6/3 cable at 60 degrees Celsius is 55 amperes. But that number increases to 65 amperes at 75 degrees Celsius. The maximum amount of electrical current capacity that 6 AWG cord can convey at 90 degrees Celsius is 75 amperes.

Note that a cable carrying more power than its amp rating will overheat and melt.

Even if the wire is intact, it has the potential to harm your equipment as well as electrocute the occupants of your home. That is why we stated that the ambient temperature is important.

Collectively, if you aim for the right temp rating, 6 AWG cord can handle and avoid appliance damage with electrical current requirements greater than 55 or even 60 amps.

What Is 6/3 Wire Used For?

What Is 6/3 Wire Used For?

Hot tub, stove, Tesla charger, and electric range might utilize 6/3 cables. These gadgets won’t always operate with 6/3 wires in all circumstances because they are based on the cable’s amp rating. For instance, the amp wire size suit stoves with ratings between 55 and 75 amps.

A common use of this line would be from the property’s electrical penal, where electricity is distributed to various connected devices in the region. Furthermore, according to some electricians, a 6/3 wire can serve as an underground feeder. 

Does The Material Have An Effect On The Amp Rating? 

Certainly yes. The ability of each substance to carry electricity varies. Copper wire is an excellent conductor for moving current, while silver is the best one. Plus, aluminum wire is the metal primarily utilized in the infrastructure of power systems.

The copper vs. 6/3 aluminum wire amp rating is described following table:

Copper wire 55 amps65 amps75 amps
Aluminum wire 40 amps50 amps55 amps

After looking at the above table, you may understand why your 6/3 amp cable may not transport as much current ratings as your neighbor’s 6/3 amp wire gauge because you might use aluminum instead of copper material. 

Despite the conductors being the same size, copper has better conductivity than aluminum.

Does Its Amps Change With Distance?


The distance influences your wire cable since it triggers the voltage drop. The current ratings sent via a wire to a gadget at the other endpoint will meet resistance. 

Resistance reduces the amount of electrical current capacity that reaches the widget. If the voltage drops significantly, the device may cease to function.

Due to its lower resistance, a bigger cable can transport more power. When the distance increases while the amp wire size remains constant, the resistance generates more heat than the wires can withstand. Hence, you risk sparking a fire.

With 120 volts, 240 volts, and 480 volts,  a 6/3 wire gauge may be run a maximum of 76 ft, 153 ft, and 306 ft, respectively. You can refer to this useful info to adjust the distance properly without significantly dropping the voltage.


How Far Will 6 AWG Wire Carry 50 Amps?

Our brief answer is a 100-foot run of 6 AWG gauge wire rated for 50 amps. The voltage decreases by 20% per 100 feet.

Can 6 Gauge Wire Handle 70 Amps?

Yes. According to our discussion, a 6 AWG gauge wire with a copper cable can carry 55 to 75 amperes, whereas an aluminum one can support 40 to 55 amperes.

Which 50 Amps Wire May Power Electrical Appliances? 

The AWG wire size meant for this ampacity is 6 gauge with 65A.

Time To Recap

You’ve read thus far, and you’ve understood the 6/3 wire amp rating. Remember that the wire’s ability to conduct electrical current is influenced by its construction, temperature, electrical insulation, and resistance.

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Automotive Mechanic at PowerAll

With 7 years experience in management positions leading automotive mechanics at PowerAll, Erik Watkins wishes to share useful knowledge and information about automotive mechanical equipment.


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