How Many Watts Can 4 Gauge Wire Handle?

Sometimes, it is challenging to get the proper wire for certain appliances. As such, determining the right gauge wire for your appliance, especially the amplifier, is quite important. This becomes crucial when it comes to installing car audio. Or else, it might impact the whole car audio system.

In that case, you may ask your friends or even do a bit of research to find out how many watts can 4 gauge wire handle. If you are looking for the right answer, this post might be helpful for you. Keep in mind that you don’t have to be an electrician to understand the basics of wiring.

Having the right information on the wattage, voltage, and amperage of different types of appliances concerning the wiring can get you good results in case of a potential DIY repair.

Let’s find out how many watts can a 4-gauge wire handles in the best possible way.

How Many Watts Can 4 Gauge Wire Handle

How Many Watts can a 4-Gauge Wire Handle?

Now that you bought an amplifier and a subwoofer, all you have to do is hook them up. But how to determine the type of gauge wire you need for the purpose? Although most amplifier kits will have the recommended watt printed on the box, there’s a whole story behind it.

A common rule of thumb is that you need 8 gauge wire for up to 500 watts. This is the right wattage that might go well with an 8-gauge wire. When it comes to running a 4 gauge wire, the watt should be anywhere between 500 and 1000.

If your appliance falls in this range, you can use a 4 gauge wire and it will work efficiently. If you want to run 2 gauge wiring, the watt should be between 1000 and 1500. Lastly, if you want to run a 0 gauge wire, the watt should be over 1500.

However, the actual watt to be consumed depends on other factors as well. It may include temperature settings. Also, it depends on whether the wire is made of copper or aluminum. That way, not all 4 gauge wiring can handle the same load.

There are factors to consider such as temperature ratings and type of wire, aluminum or copper. The NEC or National Electric Code has a wire gauge wattage chart showing the recommended amperages suited for both aluminum and copper along with temperature ratings.

Is there any Difference between 4 Gauge Aluminum and 4 Gauge Copper?

As you know, aluminum is a metal that can resist both heat and current. As a result, aluminum wiring with the same gauge will never have the same amps compared to a similar copper wire. Let’s study the temperature ratings for these types of wire.

Temperature Rating 140 degrees F 167 degrees F 194 degrees F
4 Gauge aluminium NA 65 75
4 Gauge copper 70 85 75

At a temperature of 167 degrees Fahrenheit, a 4 gauge aluminum wire can conduct 65 amps. Whereas, with the same temperature rating of 167 degrees Fahrenheit, a 4 gauge copper wire can conduct around 85 amps.

While there are different types of insulation types, they don’t affect much in terms of current. Aluminum isn’t usable at 140 degrees F. Besides, they are about 20 amps below copper wiring when the temperature rating is at 167 degrees F and 194 degrees F.

Where is a 4-Gauge Wire Commonly Used?

In general, you don’t often find a 4-gauge wiring in many applications. Additionally, it is rare to find them in most commercial or residential wiring. There are chances that manufacturing industries might use the 4 gauge wire for certain large-scale projects.

When it comes to using the wire for home, it is unlikely that you would find a 4-gauge wire in the electrical system. Even the appliances that consume much power such as water heaters, HVAC systems, dryers, and washers don’t use more than 10-gauge wire.

Moreover, your washing machine needs a 12-gauge. As it appears, there is no need for a 4-gauge wire at home. Still, you can use it for most of your appliances at home if you want to waste money. In reality, 4 gauge wire can handle 20, 15, and 10 amps with ease.

Unless you live in a big mansion, there is nothing at your home that needs thick wiring to operate. At the industrial level, you can find 4 gauge wiring for large electric heaters and massive furnaces.

How to Calculate

Moving on with the topic of how many watts can 4 gauge wire handle, it’s time for you to know how to calculate. The chart will have the 4 gauge wire watt rating and what they can handle. More on that in the later part of the post.

As said earlier, the maximum amount of watts a wire can handle depends on the wire material and voltage. For wire material, copper wires can handle more watts compared to aluminum wires of the same gauge. Besides, the watts a specific wire can handle depends on ampacity as well.

Commonly, wires carry more watts in high-voltage circuits like 220V or 240V. For instance, a 14 gauge copper wire carries around 3520 watts at about 220V. However, at a smaller voltage like 12V in batteries, the same 14 gauge can handle 192 watts only.

Before looking at the wire gauge wattage chart, let’s learn how to calculate the watts that a wire can handle. Follow this simple calculation below.

  • Find out wire ampacity – No wonder, different gauge wires will have different ampacities. Furthermore, ampacity depends on the material that the wire is made of and temperature as well. For example, 8 gauge copper wire has an ampacity of about 50 amps when the temperature is 75 degrees Celsius. Under the same condition, an 8 gauge aluminum wire will have 40 amps, which is low.
  • Follow the rule set by the NEC – The National Electric Code emphasizes that anyone can load a wire to 80% of its ampacity. It means you can put 40 amps on an ampacity of 50A copper wire. Here is the calculation: 50A x 0.8 = 40A.
  • Finally, multiply amps and voltage – To get wattage, you have to use the basic electric power formula, which is Watts = Amps X Volts. It gives the maximum wattage that a wire can carry.

Wire Gauge Wattage Chart:

Below mentioned are the watts and amps that a 4 gauge wire can handle.

Voltage 4 gauge aluminum wire Amps 4 gauge aluminum wire Wattage 4 gauge copper wire Amps 4 gauge copper wire Wattage
240 Volts 52 Amps 12480 Watts 68 Amps 16320 Watts
220 Volts 52 Amps 11440 Watts 68 Amps 14960 Watts
120 Volts 52 Amps 6240 Watts 68 Amps 8160 Watts
110 Volts 52 Amps 5720 Watts 68 Amps 7480 Watts
24 Volts 52 Amps 1248 Watts 68 Amps 1632 Watts
12 Volts 52 Amps 624 Watts 68 Amps 816 Watts


At a median temperature of 75 degrees Celsius, the ampacity of a 4 gauge copper wire is 85A. According to NEC, it means that a 4 gauge copper wire can handle up to 68 amps of current.

The same has been reflected on the above 4 gauge wire watt rating chart. Therefore, depending on the voltage, the 4 gauge copper wire will carry anywhere between 816 and 16320 watts.