Contact us
Close contact box
Connect ID #
140 456 67
Connect ID #
140 456 67

Sorry, chat is currently unavailable

Don't wait on hold. We'll call you back when it's your turn to talk with the next available .
Please enter your name  
Please enter your phone number  
Please enter a message  

Calls may be recorded for training and quality control purposes.

We are located in Virginia USA.

Lead image

Car amplifier power wire fuses

How do you choose the right fuse for your amp?

Your amp power wire needs a fuse. What size fuse to use depends on the material, thickness (gauge), and length of the power and ground wires used for your amplifier's installation. In this article, we'll chart out which fuse you should use for your amp's wiring, and why.

A car amplifier's 12-volt power wiring can carry enough electrical current to burn up and destroy not only the wires themselves, but also your car. This could happen in the event of an accidental short circuit, like when a frayed power wire touches the vehicle chassis. 

To protect you and your car from an electrical disaster, a fuse must be installed on the amp power wire — as close to the car's battery as possible.

A fuse will protect you and your car from a catastrophic electrical disaster

It's dangerous enough driving around with a tank loaded with gasoline that could catch fire or explode in the event of an accident, you certainly don't want to add the threat of an electrical fire occurring under the same circumstances.  An in-line fuse on your amplifier's power wire will protect you and your car from almost any electrical disaster related to the amp's installation.

Charred wires in car

This could have been much worse

Fuse as close to the battery as possible

In the event of an accident, you wouldn't want a live power wire flopping around inside your car. The vehicle's chassis and metal body parts are all connected to ground, so when a loose power wire touches metal, a short circuit is created that produces runaway current flow and heat build-up. This is why we recommend installing your fuse as close as you can to the positive battery terminal, so no loose ends can cause damage.

Be sure to route the power wire around other things in the engine compartment so it doesn't get in the way. It's also a good idea to secure the power cable and fuse holder to the vehicle body (typically with wire ties) to keep it from bouncing around over time. (In this image, we sat the fuse holder on top of this fuse box simply to get a better photo.)

Fuse mounted by battery

Neatness counts for a power wire installation

What's current and why is it dangerous?

To help visualize the concepts, it's often useful to study an electrical circuit as if it were a closed arrangement of pipes filled with flowing water — because similar rules and limitations apply. You can think of electrical current, using the plumbing analogy, as the amount of water inside a given volume of pipe at a particular moment in time. As we pump more and more water inside that section of pipe in that same amount of time, the pressure inside the pipe increases until it reaches the maximum strain capacity of the pipe's construction material, and then the pipe bursts.

Electrical resistance generates heat

Instead of water-flow resistance raising the pressure inside a pipe, electrical resistance to current flow creates heat in the wire. Too much current flowing through a wire's resistance could overwhelm the conductor material or insulation and melt it or set it on fire. Every kind of wire has a limit to how much current it can safely handle before over-heating. 

Blown fuse

Crutchfield trainer JR shows a blown fuse

When a fuse blows, something is wrong

A fuse works by introducing a small weak metallic segment in the power circuit that's designed to pass a rated amount of current, but melt apart, safely breaking the circuit open, when that current rating is exceeded. The fuse is there to protect you.

When a fuse blows, you should thank it for saving your life, and then find out why it had to sacrifice itself, before you replace it. There's no sense in replacing a fuse that'll just blow again because the loose wire that caused the problem in the first place was never fixed.

Note: Sometimes you can't determine whether or not a fuse is blown by visual inspection, and a multimeter or continuity tester must be used to verify a broken connection or that voltage is not present on both sides of the suspect fuse.

Safety note: Never replace a blown fuse with a higher-rated fuse — that could allow the wires and your car to burn to the ground before the fuse blows.

Circuit breaker

PowerDrive 300-amp circuit breaker (#996PDSB300)

Circuit breakers

Circuit breakers are like fuses that can be re-set without needing replacement. Besides safety reasons, using a circuit breaker can come in handy if you regularly blast competition-level bass at or above your amp's power capacity, or you want a covert system-off switch so valets and mechanics can't play around with your sound system. Some people don't trust  circuit breakers because they take a little longer to trip open than would an equivalent fuse — but that really shouldn't make any difference in a car audio installation.

Maximum and minimum fuse ratings

The smallest fuse that'll work for your system should provide enough current to support your amplifier's maximum power output. The only penalty for using a fuse too small is the expense of replacing fuses that blow when the amp tries to produce its rated power. The largest fuse size to use will protect the power and ground wires from melting while also allowing maximum current flow to the amplifier, letting it produce its maximum output power.

To avoid danger, obey the limits

For safe installations, your power wire should use a fuse sized equal to or less than the maximum amperage ratings listed in the chart below. For information about what size wire to use for your amp installation, refer to our Wire gauge chart.

Power wire Max fuse size
00 AWG 400A
0 AWG 325A
2 AWG 200A
4 AWG 125A
8 AWG 50A
10 AWG 35A
12 AWG 20A
14 AWG 15A
16 AWG 7.5A
18 AWG 5A

Chart accuracy: The above chart should be used as a general guideline — many manufacturers spec their wires differently. When discrepancies occur, always use the wire manufacturers' fuse recommendations. If you're using an amplifier wiring kit, use the fuse that came with the kit.

Fuses in a fuse block

Some fuse holders use two fuses, wired together in parallel for the desired amperage rating 

Wire material: The chart is for stranded oxygen-free copper (OFC) wire about 15 feet long. Copper-clad aluminum (CCA) and solid copper household-type wiring have different current-carrying capacities, use different-size fuses, and are generally inappropriate for mobile audio applications.

Marine fuse

Kicker marine-grade ignition-protected MRBF 60-amp fuse (#20647RBF60)

Marine fuses: Regular fuses and circuit breakers often create a small spark when blown or tripped, so would be dangerous in most marine applications and wherever gasoline fumes are present. Marine-grade ignition-protected fuses and breakers are the safest way to protect your wiring when afloat.

What about the fuses onboard the amplifiers?

When fusing your main power wiring, ignore the onboard fuses your amplifiers and other devices may have. Plan your system fusing as if those fuses didn’t exist and use the fuse rated for the main power wire. Those onboard fuses are there to protect the individual devices themselves when something goes wrong internally — so even if an onboard amplifier fuse blows, the power and ground wires near it will still be electrically active and dangerous. Remember, the fuse on the main power wire protects the wiring and your life. When something goes wrong, you want power to shut off for the whole system, including the wiring.

Some amplifiers don't have onboard fuses — for whatever reasons the manufacturers have decided. In multi-amp setups that use power distribution block wiring, each amplifier without an onboard fuse will require, for safety's sake, an additional in-line fuse, rated for the amp's power wire capacity, mounted near the amp itself or the distribution block.

Which one's right for you?

Give us a call when you're purchasing an amplifier and its installation gear, so you can be sure you get the right power wire and fuse for your amplifier to safely play at its maximum potential.

  • Lyman from Owensboro, Ky

    Posted on 6/19/2023

    What size fuse do you need if you are running 2 amps off of one power supply, both amps takes 100s.

    Commenter image

    Buck Pomerantz from Crutchfield

    on 6/20/2023

    Lyman, Without knowing what "takes 100s" means or precisely what amplifiers you're referring to, we can't help you with advice. If you want a question answered about a system, you must identify the gear by brand names and model numbers so we can get the right information to you.
  • Bryan Johnson

    Posted on 6/4/2023

    Why is there a discrepancy between the recommended fuse in your table, and your wiring install kit? I bought the Crutchfield CK8 kit, which has a 60 amp fuse, but your table here recommends a maximum of 50 amp fuse for the 8 awg wire. I plan to use the fuse in the kit, but would like to know why it is oversized.

    Commenter image

    Buck Pomerantz from Crutchfield

    on 6/6/2023

    Bryan, The chart in this article is set up for maximum safety for custom-built power wiring. Different wire manufacturers spec their products differently and put together wiring kits that they feel is right for their products. Crutchfield's specs may differ - "erring" on the side of safety for our customers.
  • Alejandro Olivares from Barstow

    Posted on 4/12/2023

    I have 2 questions, first the shop I went to had installed a 60a blade fuse on both my 4 awg power wires for both my amps, is that right? Second question: I bought a 120a fuse for my pioneer amp (2400w max 1200w rms) but will I need a high output alternator for this setup?

    Commenter image

    Buck Pomerantz from Crutchfield

    on 4/14/2023

    Alejandro, It sounds like your installers know what they're doing concerning safety, no matter what amps you have. Even after adding another amplifier, you shouldn't consider adding an HO alternator unless your Headlights dim when the music plays.
  • Bob

    Posted on 4/9/2023

    I have the same amplifier as Kenneth. Rockford Fosgate R2 1200x1. According to your wire gauge fuse rating chart for the 4 gauge power wire needed for this amp it says I should run a 150amp fuse but manufacturer calls for 200 amp is it safer to trust the manufacturer rating?

    Commenter image

    Buck Pomerantz from Crutchfield

    on 4/10/2023

    Bob, Rockford Fosgate's fuse rating is for protecting the amplifier alone and not the wiring, which is more important for safety. Our fuse chart should be used as a safe general guideline - many manufacturers spec their wires differently. When discrepancies occur, always use the wire manufacturers' fuse recommendations. If you're using an amplifier wiring kit, use the fuse that came with the kit.
  • Kenneth Werwinski from Nj

    Posted on 3/18/2023

    My Rockford Fosgate, R2, 1200 Watt amplifier birth, sheet is rated at 1401 watts and it recommends a 200 amp fuse. I have that hooked up now on a four gauge to my secondary battery and it's starting to get warm. I wanted to know if that was normal and I believe for a four gauge wire and needs 150 amp fuse the question I have do you think I should switch and put the 150 instead of the 200 amp can you please help me and contact me as soon as possible thank you so much

    Commenter image

    Buck Pomerantz from Crutchfield

    on 3/20/2023

    Kenneth, You didn't say exactly what's "starting to get warm" - battery, fuse, wire, amplifier? Large current flow naturally warms up connected components and if you can keep your hand or fingers on it without getting burnt, it's usually okay. However, loose connections often result in current-cycling that produces tremendous amounts of heat and can melt wires and connectors and set your car on fire. Changing fuse size will do nothing - use the wire and fuse recommended by the amplifier manufacturer and make sure all connections are tight and secure.
  • ColinL from Wichita

    Posted on 1/30/2023

    Many hybrid vehicles today house their 12V battery under the rear seat or somewhere in the passenger cabin, and instead have jumpstart/accessory terminal connections under the hood where the battery would be found on a non-hybrid vehicle. Is it safe to connect a large gauge power wire to the 12V battery in the vehicle, or should it be wired instead to the accessory connector under the hood? Obviously the distance to the battery is far shorter than wiring to the accessory connector, so it's tempting for convenience alone.

    Commenter image

    Buck Pomerantz from Crutchfield

    on 1/31/2023

    Colin, The accessory connector may have the current-carrying capability needed for an amplifier's power cable, but connecting directly to the battery will guarantee a safer connection.

Looking for
amp wiring kits?

Amp Wiring Kits Shop our selection

Find what Fits your vehicle


Checking fit...

Compare the sound