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Why Does My Car Amplifier Power Wire Keep Melting?

Power wires for the car amplifiers are crucial parts of the car audio elements, especially with installed powerful speakers.

Unfortunately, even in the loudest car audio system, you can experience that either power or ground wire will melt. But, why does amplifier power wire melts? Let’s find out.

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In general, power wire and ground wire are overheating because of high current flow in the power cable causes heat, leading to melting of the power wire. The ground wire also can be heated up due to grounding issues.

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Tip: Car audio amplifiers need quite a lot of power, so during installation, you have to make sure to use wires of the correct size, so they can carry this power to the car amplifier without overheating or melting.

The wires that I have used for years and can recommend are the KnuKonceptz. These are 4 AWG OFC wires made of the highest quality materials and create minimal resistance.

In the article below, I will highlight possible causes of melting amplifier wires and explain how to prevent it from happening ever again.

Why Does My Power Wire Keep Melting?

The most common reason people experience melting is due to undersized wiring for your car audio system.

If you’re connecting an amplifier to the battery using for example 16 gauge speaker wire, something will burn out. You simply can’t expect such thin wires to carry 100 amps worth of current continuously without overheating and causing a wire to melt.

Why Does My Ground Wire Keep Melting?

Power wires connected to amplifiers typically get very hot due to resistance within the conductors. This happens because an amplifier adds significant heat along the power wire.

If your amplifier won’t turn on or emits an error code, you might have a grounding issue. This means if there isn’t enough metal in contact with your vehicle’s chassis to complete the circuit, then no current will flow through your audio system at all.

In addition, ground wires that are too small for the power rating of your amplifier will cause overheating, which can lead to melted insulation on both power and ground wires. In the worst-case scenario, it may even result in a fire.

An example of this would be powering an amplifier with a 0 gauge power wire when only 4 gauge wire is used for the ground. The larger surface area helps keep heat low, so things don’t get out of hand.

It is important to remember that power and ground wires must be properly sized and installed to avoid power and ground loops. If you want to design your audio system correctly, you need to have a basic understanding of Ohm’s law, impedance, and current draw.

Can Outer Coating Protect the Wire From Melting?

Although the power wire has a protective outer coating made of PVC or other insulation material, it can still overheat if the wire is too small for the amplifier’s power rating.

This can cause damage such as melting or scorching where the wire enters into contact with the terminal block on your amplifier because this area always remains hot under load conditions.

It doesn’t matter how thick your amp power wire is unless you use at least one size larger than advertised by the amplifier manufacturer (if it is specified in the amplifier specification).

When an amplifier power wire gets too hot, it can melt the protective outer coating, exposing the bare wire that creates a short circuit when it touches another metal surface.

This contact can cause fuses to blow because it rapidly draws high current levels until something fails. The insulation burns and melts when this happens, creating sometimes dangerous conditions not only for your car amplifier but for the whole car.

For this reason, you should always use wires at least one size larger than your amp’s manufacturer recommended, avoiding issues like melting wires, melted fuse holders, and other problems like ground loops through chassis ground connections.

The best way to prevent the power wire from melting is by upgrading the wire to a thicker gauge. This will increase wire resistance and lower current flow through it, making it safer for your car amplifier.

What Cause Amplifier Wires to Melt?

Several factors can cause each power cable run to overheat:

Ground Currents Are Flowing Through All Cars’ Metal Frames/Chassis.

This can happen when the ground wire is not sized correctly, or you have issues with the ground path (loose bolts, wires bolted to painted metal, etc.)

DC Power Supply Voltage Sag.

This issue occurs mainly in older cars that use mechanical voltage regulators. Voltage sags cause increased current flow through all cables that feed the power amps.

Since the amplifier power cable is doing more heavy lifting than your other cables (usually smaller than 8 AWG), it will overload first and overheat.

Drawing Too Much Current.

If you install an amplifier capable of delivering 1000W RMS and only have 500 watts going to your speakers, your power wire will sizzle.

The most common reason for this problem is that people install an amplifier capable of 2 or more times as much power as they need and then expect it to work flawlessly without any issues.

Although total RMS power from the amplifier is recommended to be larger than speakers, mounting an amplifier with 1000W RMS with a pair of speakers rated at 100 watts will overkill the wires.

Poor Car Audio Design or Installation.

Although I have never seen this happen on any car audio system, the ground wire should be bolted down to the vehicle’s chassis and not somehow attached to the metal panel.

If you do not want to bolt a ground wire to the chassis, another way is to make a solid connection of the ground wire directly with the car battery.

Low-Grade Wiring Is Used for the Power Cable.

Many “no-name” manufacturers use low-quality materials in their power cables, resulting in overheating when carrying high currents.

When a strong amplifier relies on a low-grade power cable, this will eventually result at least in the melting of the insulation.

Driving Multiple Amplifiers of the Same Power Wire.

Two amplifiers sharing the same power wire may result in the melting of one power cable, so make sure the wire is thick enough to support their combined power.

How to Prevent Car Amp Wires From Melting?

These are few key points you have to remember if you want to enjoy the car audio without burning your power wires:

Make Sure You Are Using a High-Quality Power Cable.

You can buy amplifier power cables at many Car Audio stores, but be aware that some shops may not offer you the highest quality products. 

Instead, they might sell you low-grade power cables, so be careful and look on the package for “power wire,” NOT “speaker wire.”

Keep Your Power Cable Runs as Short as Possible.

The shorter the path of the current, the less resistance there is in it. This means that if you carry twice the same current through two wires with half the cross-sectional area, they will heat up to almost double degrees.

Use the Correct Wire Gauge for Your Amplifier Wires.

The thickness of the wire should be directly related to the total RMS power from the amp.

For example, if you use an amplifier only for direct replacement of your factory speakers, then 10AWG or 12AWG wires should be acceptable.

However, when you power a strong subwoofer (or several of them), you should use wires not thinner than 6AWG.

The table below shows the relation of the power and ground wires thickness to the total RMS power for your amplifier:

Wire GaugeTotal Amplifier’s Wattage (RMS)
12 AWG40 – 100 W
10 AWG100 – 200 W
8 AWG200 – 400 W
6 AWG400 – 600 W
4 AWG600 – 1,000 W
2 AWG1,000 – 1,500 W
0/1 AWG1,500 W or more
How Many Watts Can Amplifier Wire Handle Depending From the Gauge

Bolt Your Ground Cable With Bare Metal.

If the ground is bad, then it can cause overheating as well.

Use a star washer, lock washer, and nut to ensure good grounding. Make sure that ground wire has the same thickness as the power wire.

Keep Your Amplifier Clean From Dust.

If the amplifier heats up too much due to a lack of proper ventilation or condensed dust, this can also lead to overheating and melting power wires.

Why Does My Fuse Holder Keep Melting?

Fuse holders can also melt, but the reasons are a bit different.

If you have just connected a new power cable to your amplifier and fuse holder, but this connection is loose, this place will have too much resistance, and the plastic fuse holder will melt due to overheated wire.

It can also happen due to moisture if you live in a humid climate and the power wire is not connected correctly and insulated.


Power wire will melt when the current flow through it is more than it can handle. This can happen due to higher voltage applied to the amplifier or incorrect wiring in the electrical system.

It also happens due to short circuits or ground wires that are too thin and not doing a good job of grounding the car amplifier.

The power source for car audio amplifiers is complicated to manage because power cables draw so much current and create heat almost immediately, even if they’re no faults anywhere in your installation.

To solve this, make sure your power cable is large enough and rated for the amplifier you’re powering. This will help prevent melting and allow you to enjoy lower power consumption and better efficiency from your car amplifier.

Another thing that might cause wire-melting issues is incorrect wiring or grounding of the car audio system. You could also be dealing with a short circuit resulting from faulty installation or poor wires choice.

If you have found yourself wondering, “why does my amplifier keep melting its power wires?” consider getting new high-quality power wires and be sure the amp is correctly grounded.