what size breaker for 3.7 hp air compressor

What Size Breaker for 3.7 HP Air Compressor? Choose the Right One


Figuring out the right breaker size for your 3.7 HP air compressor can be very frustrating. Especially when there’s little to no information available about it. You’re mostly left on your own to figure it out.

What size breaker for 3.7 HP air compressor?

You should use 20 amp breakers for your 3.7HP air compressor. Most manufacturers state that you’ll require a 15 amp breaker for a 3.7HP air compressor. But that’s just playing with fire. Electrical compressors pull extra current at the startup, which can trip your 15 amp breaker.

Not satisfied with the short answer? Then you better buckle up! This article will clear up all your confusion surrounding air compressor breakers.

Figuring out the Right Breaker for Air Compressors

Choosing the proper breaker size doesn’t only save you energy, but it’ll also keep you safe.  

Modern-day standard air compressors usually need around 15 amp breakers to operate. Manufacturers also recommend the 15 amp breakers for most of their selected air compressors. However, a closer inspection can bring out some hidden facts.

If your compressor doesn’t correctly fit the size of your breaker, it’ll frequently overheat. Your air compressor will also constantly trip the breaker. This damages your air compressor in the long run and carries significant risks of short circuits.

So how do you figure out the right breaker size for your air compressor?

The amperage ratings determine the size of the breaker. And you’ll require the right breaker size for air compressors.

Here’s how you can calculate the required amperage for your air compressor in two simple steps-

Step 1: Determine the Power Wattage

We’ll start off by converting the HP(horsepower) to watts. 1 Horsepower equals 745.7 watts.

Check the HP rating of your air compressor and multiply the value by 745.7. This will give us a rough idea about the power wattage your air compressor demands.

Step 2: Figure out the Amperage

You can find out the wattage value by multiplying the amperage with voltage. Hence, to figure out the amperage, you’ll need to divide the wattage with voltage.

Check the motor of the compressor to learn about its voltage requirements. Divide the wattage with the voltage value, and you have the amperage.

It’s that simple!

Compressor motors have a tendency to draw extra power at the startup. This means that you shouldn’t rely on breakers with the exact amperage requirements. Aim for breakers with a higher amperage to avoid tripping from the excess power draw.

Proper wiring of the circuit should always be emphasized. Failing to do so will render your double socket unusable.

Appropriate Breaker Size for 3.7 HP Air Compressor

We’ve learned how to measure the amperage requirement of an air compressor in the previous segment. It’s time to put that newfound knowledge of ours to the test.

We’ll figure out the breaker size for 3.7 HP air compressors using the same method-

A 3.7 HP air compressor will use about = 3.7*745.7 watts

                                                               = 2,759.09 watts.

Now, most 3.7 HP air compressors have a voltage requirement of 230V. We’re going to go with that value in this calculation.

Amperage required for a 3.7 HP air compressor = 2,759.09/ 230 amps

                                                                             = 11.99 amps

According to our calculation, a standard 3.7 HP air compressor requires almost 12 amps. The recommended 15 amps breaker should be able to fit just fine with it. 

But that’s not all. We’re yet to consider the extra power consumption at the startup.

The compressor motor can take up to 60% extra power at the start of the startup. In that case, the 15 amps breaker won’t be enough for your air compressor. So with that in mind,  we must secure a breaker with at least 80% more amps. 

That leads us to prefer the 20 amps circuit breaker for a 3.7 HP air compressor. With it, you won’t have to worry about your air compressor overheating or tripping the breaker. 

Electrical boilers also use somewhat similar voltage as the air compressors. So you might need to fit 20 amp circuit breakers with your electrical boiler as well. You can face problems with Hydro Shark boilers if you fail to meet the requirements.

Want to buy a 20 amp circuit breaker for your 3.7 HP air compressor? Have a go with these circuit breakers that we’ve picked for you-


These double-pole 240V circuit breakers can constantly meet the power demand of your air compressor. 

It’s important to maintain safety standards for using circuit breakers. You must follow the NEC(National Electrical Code) standards for establishing voltage supply to the circuit. 

The air compressor consumes high voltage. So it would be wise to have a dedicated circuit just for your air compressor. 

You should also only use extension cords that exceed the minimum specification requirements. Avoid series circuits as you’re not lighting garage lights in series.


Question: Should I get a 60 amp circuit breaker for a 5 HP motor?

Answer: Yes. 60 amp is the recommended circuit breaker for a 5 HP 230v motor. Always make sure to check if the motor has overload protection.

Question: How much time does a 60-gallon air compressor require to fill up?

Answer:  It’ll take about a minute for a 60-gallon air compressor to go from 90-psi to 125. The number will increase to around 5 minutes if it starts filling from 0-psi.

Question: Is a 60-gallon air compressor considered big enough?

Answer: Yes. A 60-gallon air compressor can handle high-intensity jobs. They are designed to last a long time and provide consistent service. You can find a lot of 60-gallon air compressors that are made for industrial jobs.


Hope this article answered your query on what size breaker for 3.7 hp air compressor. Establish all the necessary safeguards for safe circuit usage. Ask for your local electrician’s help for any electrical appliance-related inquiries.

Stay safe!

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