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What Size Fuse for 1500 Watt Amp? – Ensure Amp Safety

Written by Edwin Jones / Fact checked by Andrew Wright

what size fuse for 1500 watt amp

A fuse is a must-have for an amplifier to prevent irreparable harm if an accidental overload or short circuit occurs. Now, you’re wondering, “what size fuse for 1500 watt amp?”

A 1,500-watt amp for a car typically requires a 125-amp fuse. But it might not be the case for some amplifiers.

Here, you’ll learn how to calculate the right fuse with an amp. Continue reading, and you’ll also look into the factors affecting fuse size selection.

Fuse Size for 1500-Watt Amp


You can use math to determine the fuse size needed for a 1,500-watt amp. The formula to use is the following:

\[ \text{Current} = \frac{\text{Wattage}}{\text{Voltage}} \]

Generally, a car amplifier requires 12 volts to run. Using the given values, modify the formula to find the current needed for the fuse, so it becomes the following:

\[\text{Current} = \frac{1500 \, \text{watts}}{12 \, \text{volts}}\]

So, the current that your fuse should handle is 125 amps. However, car stereo fuses typically require more than the maximum current potentially generated.

Next, you must determine the amp’s class efficiency. For example, a Class C amplifier is usually 80% efficient. Now, multiply 125 amps by 20% to get 25 amps. Add this result to the previous answer to get 150 amps, which should be the max fuse size.

Apart from manual calculations, you can use an online amp fuse size calculator to help discover the correct model. Alternatively, you may look into the amp’s owner’s manual for information about the correct fuse.

Factors Influencing Fuse Size Selection

Note that using math to find the right fuse for amplifier is generally only one step of the entire fuse-selection process. Consider other factors to help ensure you’re using the correct fuse for your 1,500-watt amp.

1. Wire Gauge


The amp’s wire size can affect the fuse needed for the system to run safely. Look into the American Wire Gauge (AWG) of the cable used in the amp. Here’s a wire size chart to help you gain an idea of the maximum current that a cable can handle:

AWG Gauge Maximum Current
0 300 amps
1 238 amps
2 188 amps
3 150 amps
4 120 amps

2. Amp Class Efficiency


As mentioned earlier, the amp’s class efficiency can affect your fuse-buying decision. Here’s a list of some different amplifier classes and their estimated efficiency ratings:

  • Class A: 30%
  • Class B: 50%
  • Class AB: 5% to 10%
  • Class C: 80%
  • Class D: 100%

Frequently Asked Questions

What Size Fuse Do I Need For A Subwoofer?

Determining the subwoofer fuse to use typically follows similar rules in searching for the right amp fuse. Still, a 60-amp fuse for a subwoofer can be a good starting point.

What size fuse do I need for a 3000-watt amp?

For a 3000-watt amp, we suggest using a minimum 25 Amp fuse.


Remember, finding out what size fuse for 1,500 watt amp is critical to safeguard the system against potential harm. A 125-amp fuse can be an ideal starting place for a car amp.

But don’t forget to check other factors, such as the amp’s class efficiency and wire gauge used, before buying and installing a fuse for the system. You can use manual calculations to find the right fuse. Alternatively, online calculators exist for this purpose.

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