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What Gauge Wire for 500 Watt Amp? (Answered)

Written by Edwin Jones / Fact checked by Andrew Wright

What gauge wire for 500 watt amps

Choosing the proper wire size is essential to achieve optimal car amplifier performance. However, when determining the right wire for an amp, several factors might need to be considered.

In this article, we’ll show you what gauge wire for 500 watt amp is best recommended. Furthermore, we will also provide all the necessary information on this task so you can use it to determine other amplifiers with various power ratings.

What Gauge Wire for a 500-Watt Amplifier and Why?


When getting the proper size wire of an amplifier, there are several things you should understand. First, you need to determine the total current draw of the amp unit and then choose the appropriate wire size that can handle this power rating.

Therefore, it would be best if you also understood AWG, which refers to the measurement of wires. You should know that the lower the gauge number, the larger the wire conductor size. Meaning it has more potential to hold more current.

How to Determine Gauge Wire

To determine the proper wire gauge for the amp, you may need to do some simple calculations. This might include the total RMS rating, voltage system rating, and amps efficiency. If you wonder why the amplifier’s efficiency needs to be considered, it’s because not all amp units can run at 100% efficiency.

You can check all of these details in the amplifier’s manual. Then you can use this formula:

\[ \frac{{\text{Total RMS Wattage}}}{{\text{Amp Efficiency Rating} \times \text{System Voltage}}} = \text{Total Current Draw} \]

After that, you can now refer to the wire gauge calculator below to know the recommended wire gauge for the amp. Please note that each wire size may have a limit for the current it can hold the base on your needed length.

Amp Rating Recommended size of wire per length of application (AWG)
Below 4 ft. 4-7 ft. 7-10 ft. 10-13 ft. 13-16 ft. 16-19 ft. 19-22 ft.
125-150 amps 8 6-4 4 4 2 2 2
105-125 amps 8 8 6-4 4 4 4 2
85-105 amps 8 8 6-4 4 4 4 4
65-85 amps 10 8 8 6-4 4 4 4
50-65 amps 10 10 8 8 6-4 6-4 4
35-50 amps 10 10 10 8 8 8 6-4

For a better understanding of the task, here are the two most common types of amplifiers that come at different efficiency, considering both come with 500 watts power rating at 13.8 system voltage.

Class AB Amp


Class AB amps generally have a 50% efficiency rating. Therefore, if you have a 500 watts amp with a system voltage rating of 13.8 volts, the calculation should be like this: 500 watts divided by 0.50 efficiency rating divided by 13.8 system voltage will get a total current draw of 72.5 amps.

When you look at the awg amp chart, you will see that the minimum recommended wire size is 10 gauge or up to 4 gauge depending on the length you need in your application.

Class D Amp


The class D amp type, on the other hand, is much more efficient than the class AB amp. It generally has an efficiency rating of 80%. The same formula should be used to get the recommended wire size in with this type of amp.

500 watts divided by 0.80 efficiency rating divided by 13.8 system voltage; you will get a total amp draw of 45.3 amps. Then look at the wire gauge amp chart, and you will see it will require a minimum wire size of 10 gauge up to 6- or 4-gauge wire, depending on the length of wire you need.

Now that you’ve determined the correct wire size for the amp, there’s some more information you need to know. This includes what kind of wire and conductor you want to use.

In this case, since our topic is car audio, it would be best to use a stranded wire as it is more flexible and easier to install in any vehicle. At the same time, it’s important to note that Oxygen Free Copper (OFC) is more efficient than Copper Clad Aluminum. (CCA).

Choosing CCA wire over OFC wire will help you save money. However, since it is less effective, you may need to step up the wire size over the recommended wire size in the amperage chart to make your amp more efficient.

Frequently Asked Questions


Why Use 13.8 System Voltage Instead of 12 Volts?

Car electrical systems may range from 12v to 14 volts, especially when running. Utilizing a 12v or 14v as a standard system voltage may result in a more significant or much lower 12v wire gauge. Therefore, 13.8 system voltage is used as the safest rating for different vehicle electronics.

4 Gauge Vs 8 Gauge, Which Is Better?

Both wire gauges are essential depending on what suits your needs. Most of the time. An 8 gauge power wire is essential for a 500 watts amp.

However, if you plan on installing an additional amp or other electrical components that increase the current draw of your sound system, it’s advisable to consider using a 4-gauge wire.

What Happens if I Oversize the Wire?

Oversizing a wire may not cause any harm to an amplifier. However, it may be a waste of money since it is more than what you need.


Knowing what gauge wire for 500 watt amp is one of the ideal ways to ensure optimal performance while preventing electrical risk in a sound system. This way, you can enjoy listening to the high-quality sound of your sound system without any distractions.

Keep in mind that choosing the right type of wire and conductor is equally important as the wire gauge. Even though this is simple knowledge about electricals, it can greatly impact a sound system installation.

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