What Size Breaker For 3.7 HP Air Compressor: Step-By-Step Guide

What Size Breaker For 3.7 HP Air Compressor


Many people get confused about the appropriate size of the breaker of an air compressor. Getting the right breaker size is important for the safety and efficient operation of your 3.7 hp air compressor. 

So, what size breaker for the 3.7 hp air compressor is appropriate? 

A 20 amp circuit breaker is appropriate for your 3.7 hp air compressor. Typically, A 3.7 hp air compressor would require a 12 amp breaker. However, as start-up surges demand up to 60% more power, a 20 amp breaker is the correct size. It will ensure safety and good function of your air compressor.

In this article, we will determine and explain to you the appropriate breaker size for your 3.7 hp air compressor. Keep reading!  

What Size Breaker For 3.7 HP Air Compressed 

A circuit breaker is an essential safety device for your air compressor. It  automatically disconnects the power when the current is too high.

However, if the circuit breaker is too small, it trips a lot and harms the compressor. On the other hand, if it’s too large, it can overload wiring and cause danger. So, choose the right size for safety and good function.

Now let’s determine the appropriate breaker size for your 3.7 hp air compressor step by step:

Step 1: Check the Compressor’s Electrical Requirements

Firstly, you have to review the manufacturer’s specifications to determine the electrical requirements for your air compressor. Note the information provided about voltage, amperage, and phase. 


Typically, a 3.7 hp air compressor will need 230 volts of voltage, while older models may need 240 volts of voltage. 

What Size Breaker For 3.7 HP Air Compressor

Step 2: Calculate the Required Amperage

To calculate the required amperage, first you will need to convert the horsepower to watts. This can be done by simply multiplying the horsepower by 746 watts. So, we can calculate the wattage  for your 3.7 hp air compressor: 

(3.7 hp × 746 w) = 2,760.2 watts

Now, let’s calculate the required amperage by using the following formula:

Amperage = Watts / Voltage

Considering that your compressor needs 230 volts,

Amperage = 2,760.2 watts  / 230 volts  = 12 amps

So, a 12 amp breaker is required for your 3.7 hp air compressor.

Step 3: Choose The Appropriate Breaker Size

After you have determined the required amperage for the breaker of your air compressor, it’s time to choose the appropriate breaker size.

When an air compressor starts up, its motor requires up to 60% of the total power that the compressor uses. That’s why it’s important to choose a breaker that is able to handle the electrical demands and start-up surges.

In general, the breaker should be at least 125% to allow these start-up surges. So, for your 3.7 hp air compressor, it would be 1.25 times of the required amperage which is 15 amp. 

In this case, we would recommend you to use a 20 amp circuit breaker as it is the next breaker size you can choose. It will allow for a safety margin to accommodate any start-up surges. Also, it will provide sufficient capacity to handle the electrical demands.
What Size Breaker For 3.7 HP Air CompressorSource: amazon

Step 4: Verify Wiring and Connection

It is essential to verify that the wiring and connection to the breaker and your compressor are correctly installed. You have to make sure that the wiring can handle the required amperage of your air compressor. 

Also, check that the connection is tight and secure. If you’re using a double sided socket to power your air compressor, make sure it can handle the required amperage for your air compressor.

Circuit Breaker Installation Cost 

Installing a 20 amp circuit breaker involves the cost of the breaker itself as well as the installation fee charged by a professional technician. The average cost of a 20 amp circuit breaker is between $6 to $80. 

In addition, a professional technician will charge you from $75 to $200 on average to install the circuit breaker. So, to install a 20-amp circuit breaker you have to spend anywhere from $80 to $300 or more in total.

Tips For Installing and Maintaining The Circuit Breaker

Here are some tips for installing and maintaining the circuit breaker for your air compressor:

  • Follow NEC Standards: You should always follow the NEC standards for establishing voltage supply to the circuit. This will ensure that your circuit is safe and meets the required electrical codes.
  • Use Dedicated Circuit: Using a dedicated circuit for your high-voltage air compressor is important to avoid electrical hazards and ensure optimal power supply.
  • Avoid Extension Cords:

Extension cords have the potential to cause fire when they do not meet the minimum requirements. If you still want to use it, make sure the extension cords exceed the minimum specifications.

  • Don’t Use Series Circuits: Series circuits should never be used for air compressors unlike garage series lighting as they can cause voltage drops and other electrical issues.
  • Perform Regular Maintenance: Clean the circuit breaker to remove dust. Check for any sign of damage and replace faulty breakers immediately to avoid any potential hazards.

By following these tips, you can ensure that your air compressor is safely connected to a properly installed and maintained circuit breaker. 

How to Install a 20 AMP Circuit Breaker / E3


How Many Amps Does an Air Compressor Use?

Small air compressors typically draw around 20 to 30 amps. On the other hand, the larger air compressor models can draw up to 50 amps or more. However, the amps used by an air compressor can vary widely depending on its size and specifications. 

What Size Breaker For a 220V 5 HP Air Compressor?

For a 220V 5 HP air compressor, you need a breaker of at least 30 amps. However, it’s important to check the manufacturer’s specifications for the exact current draw and recommended breaker size. Also, make sure the wiring and other electrical components are appropriately sized.

What Size Breaker Do I Need For A 7.5 Hp Air Compressor?

For a 7.5 HP air compressor , you will need a breaker around 35-amp to power it safely. Check the motor data plate for the full load amps and use the formula: Breaker size = (1.25 x compressor full load amps). 


In conclusion, it’s important to know what size breaker for the 3.7 hp air compressor is appropriate to ensure safety and optimal performance. A 20 amp circuit breaker is recommended due to the start-up surges that demand up to 60% more power.

Don’t forget to perform regular maintenance to ensure a safe and efficient operation of your air compressor. Good luck!

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