Car Amplifier Fuse [SIZE CHART & FORMULA]

Car amplifiers, or car amps (for short), are a popular aftermarket accessory for improving the audio quality experience in vehicles.

They are paired with the car’s audio system to provide the sufficient power needed to drive hi-fi speakers and deliver high-quality sound. However, amps are of different sizes and specs; you just need to use the right one for your car stereo.

Using the wrong fuse for your car’s audio enhancement can result in electrical faults and potential damage to the amplifier or other electrical parts of the vehicle. So, in this article, we will explore the importance of car amplifier fuse and other things you should know.

What is Car Amp Fuse?

A car amp fuse is a small, protective device designed to break an electrical circuit when excessive current passes through it. This tiny device comprises a metal strip or wire inside a protective housing.

When high/excessive current tries to pass through the fuse, the wire or metal strip would melt or break, thus, preventing the high current to continue its movement, and by so doing, the amplifier won’t get damaged due to the excessive power coming to it.

Car amp fuses play a huge role in safeguarding car audio amplifiers from electrical faults and potential damage by acting as a barrier between the power source and the amplifier.

More so, by interrupting the electrical flow when necessary, fuses help prevent fires and equipment failures. But then, you need the right fuse size and type for your need.

Care to know more? Car amp fuses have specific resistance levels, depending on the type and size. The fuse heats up when current flows through it, so, when the current is exceedingly high, the heat generated would be more than the fuse can resist, thus, causing it to break out and stop the current flow.

Types Of Car Amp Fuses

1. Blade Fuses

This is the most common type of car amp fuse used in vehicles today. Blade fuses, also called spade fuses, have a plastic body with two metal prongs that fit into slots in the fuse holder. Of course, they are available in different sizes and amperage ratings – very versatile and widely compatible.

2. Glass Tube Fuses

As the name implies, this type of car amp fuse is made with a glass tube with metal caps on each end. Inside the tube is the metal strip or wire that acts as the fuse element. You’d mostly find this fuse type in older vehicles.

3. Micro Fuses

Micro fuses are very small – smaller than the others mentioned above. They are more like a smaller version of blade fuses – commonly used in compact electronic devices and some car audio systems. They occupy less space and still provide good protection.

4. Maxi Fuses

Maxi fuses are the biggest you’d find out there; they are higher-capacity fuses used in applications that require higher current protection. You’d find this type of amp fuses in heavy-duty vehicles, RVs, and audio systems with high power demands.

Car Amplifier Fuse Sizes and Ratings

Car amp fuses are available in various sizes, and it is important that you choose the correct size for your specific amplifier. The commonest sizes in the market are mini (ATM), standard (ATO/ATC), and maxi (APX). Each size corresponds to a specific physical dimension to ensure compatibility with fuse holders.

Fuse ratings explained

Amplifier fuses are rated based on their current-carrying capacity; the rating is indicated in amperes (A). The amperes rating of a fuse indicates the maximum current the fuse can safely handle without breaking the circuit. So, it means that when the current exceeds the amperes of a fuse, the circuit will be terminated by the fuse.

When buying a new car amp fuse, it is important that you know the recommended amperes rating set by your car’s electrical system manufacturer. Usually, amplifier manufacturers will clearly state the power handling capabilities of each model. Nevertheless, there’s a way to calculate the fuse capacity needed by an amplifier.

Car Amplifier Fuse Formula

Here’s the general formula to use in determining the fuse size you need for your car amplifier or any other electrical setup.

Divide the maximum power rating of your amp by the voltage reading of the alternator, which is:

Max power rating of the amp ÷ voltage rating of the alternator = amp fuse rating

For example, if you have a 150W max power amp and your car’s alternator outs 14 volts, you will need an 11amps fuse.

150/14 = 10.75 amps.

So, basically, you need an 11A amp fuse.

Car Amp Fuse Size Charts

Power Wire SizeMax Fuse Size
0 AWG325A
2 AWG200A
4 AWG125A
6 AWG75A
8 AWG50A
10 AWG30A
12 AWG20A
14 AWG15A
16 AWG10A

The chart above shows the recommended fuse rating/size for different AWG measurements. In America, fuses are mostly classified with AWG (American Wire Gauge) – a unit-less US-standard measure to indicate the diameter of electrical conductors (mostly wires).

AWG ratings have an inverse relation with the diameter of the electric conductor, which implies that the higher the AWG, the lower the diameter. So, a wire with a 12-AWG rating will be thicker (higher diameter) than a 14-AWG wire.

Amp Fuse Chart By Wattage

Up to 100 Watts10 Amps
101 Watts to 300 Watts20 Amps
301 Watts to 500 Watts30 Amps
501 Watts to 800 Watts40 Amps
801 Watts to 1200 Watts60 Amps
1201 Watts to 1800 Watts80 Amps
1801 Watts and above100 Amps

Amp Fuse Chart by Fuse Size

Fuse SizeAmperage RatingCommon Applications
Mini (ATM)2A, 3A, 5A, 7.5A, 10A, 15A, 20A, 25A, 30ASmall amplifiers, speakers, and accessories
Standard (ATO/ATC)5A, 7.5A, 10A, 15A, 20A, 25A, 30A, 35A, 40AMost car amplifiers and audio systems
Maxi (APX)20A, 30A, 40A, 50A, 60A, 70A, 80A, 100AHigh-power amplifiers, heavy-duty applications

When Do You Need to Change a Fuse?

If you notice that your current fuse is blown, you should get it replaced with a new one. Some common blown fuse symptoms include a burning smell, loss of power to the amplifier, and no sound (due to a low power supply). So, when you notice any of these signs, it’s advisable to check the fuse and change it.

How to Replace a Blown Fuse

  • Turn off the amplifier and disconnect it from the power source
  • Look out for the fuse holder – you’d find this near the amplifier or in the vehicle’s fuse box.
  • Disassemble the fuse box and remove the blown fuse using a fuse puller or a pair of needle-nose pliers.
  • Put the new fuse you already got
  • Reconnect the amplifier to the power source and test the system.

Frequently Asked Questions

Can I Replace a Blown Fuse With a Different Type of Fuse?

If the new fuse has the same amperes rating as the old one you want to replace, then you can actually use it. However, it is always advisable to use the same type of fuse to ensure compatibility and fit.

Are Aftermarket Fuses Better than Stock Fuses?

Whether aftermarket or stock, you should buy your car amp fuses from reputable stores and always go for the top brands known to produce quality stuff. But then, many people believe aftermarket fuses from reputable manufacturers can provide better reliability and performance.

Can I Install Multiple Amplifiers With A Single Fuse?

Yes, it is possible but not recommended. The best practice is to use a single and separate fuse for each amplifier. So, if you have five amplifiers, you need five fuses that meet the power/circuit specification and power of those amps. 


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