A circuit breaker is an electronic safety device that prevents the flow of current when an over-current event occurs. Most air compressors have a built-in circuit breaker that performs these functions to protect the air pump and compressor. When a circuit breaker trips, it will completely remove power from the system, thereby shutting down the air compressor.

There are many reasons why your air compressor keeps tripping the circuit breaker, but the most common problem is a failed start capacitor. It could also be a clogged or blocked air filter, a damaged extension cord, a clogged compression cylinder, or even a bad motor. Other things that could cause this problem are a failed pressure switch, a bad circuit breaker, or a bad unloader valve.

If your air compressor is constantly tripping its built-in circuit breaker, then there is definitely some sort of problem with your machine. In this article, we will go over all the top reasons why your air compressor keeps tripping the circuit breaker. We will also discuss some things you can do to resolve this problem.

Air Compressor Trips Circuit Breaker

When the air compressor tank is drained down to a certain point, the pressure switch is activated, which turns the compressor pack on. The air compressor will then continue to run until the tank has reached its set pressure level.

When the pressure switch is activated, current flows through the pressure switch and into the compressor motor, where it then flows to a capacitor to start the system.

Some small compressors don’t need starting capacitors, so not all compressors have them. A compressor with a larger motor, however, will require the capacitor to support the higher amount of inrush current.

If there is something that is preventing your compressor motor from turning over, the motor will draw more and more power to try and fight this resistance. If it pulls enough amps, it will exceed the capacity of the built-in breaker. This will make the breaker will trip.

Why A Compressor Circuit Breaker Trips

There are several different reasons why your circuit breaker trips when using an air compressor. Here are some of the most common ones:

  • Clogged or blocked air filter
  • Damaged extension cord
  • Clogged compression cylinders
  • Bad Motor
  • Failed pressure switch
  • Failed capacitor
  • Bad circuit breaker
  • Bad unloader valve

Air Filter

An air compressor circuit breaker can trip if you have a clogged air filter. In fact, the air filter doesn’t have to be completely clogged for this to happen. Remember, the more an electrical motor’s operator is resisted, the power it has to draw to keep spinning.

When an air compressor has a dirty air filter, the air compressor motor has to work harder than it normally would have to. If this effect is pronounced enough, such as in the case of the filter being extremely dirty, it may just cause the motor to work hard enough to trip the circuit breaker.

So, if your air compressor is always tripping the circuit breaker, take a look at your air filter. If it’s dirty, either clean or replace it and see if your air compressor is working normally again. If it’s not, then continue troubleshooting.

Bad Extension Cord

Most air compressors are powered by electricity, but they don’t include very long cords. So, most of the time, an air compressor is used with an accompanying extension cord. An extension cord that has any kind of break or loose connection in it poses a serious fire risk. As you remove material from a conductor, it lowers its ability to handle a given current. 

So, if there is a break in the line somewhere, it can cause your equipment to consume far more amps than it otherwise normally would. This kind of fault in an extension cord will trigger the circuit breaker to prevent a fire.

Also, if you are not using the right extension cords, it will function a lot like a broken or damaged extension cord. So, you could be under powering your compressor motor, which over a long period of time, will cause damage.

For these reasons, it’s best to not use an extension cord and to rather use a long air hose to get the compressed air to where you need it.

If you rely on an extension cord to get your air compressor closer to your work area, you run the risk of damaging the equipment, while using a long air hose to achieve the same result does not.

Clogged Cylinders

If you have a reciprocating air compressor, there is a possibility that one or more cylinders are partially or fully clogged. A partial clog will hurt performance of the compressor and it will cause it to draw more current than usual. As you would expect, this can cause the circuit breaker to trip.

Faulty Circuit Breaker

Even though the circuit breaker is a device used to prevent failure to other devices, there is a chance that the circuit breaker itself is the device that has failed.

The great news is that air compressor circuit breakers are easy to find and simple to replace.

Faulty Motor

This one is pretty much the worst-case scenario. Air compressors are made with some of the highest-capacity, low current draw induction motors you can get. If you have a faulty motor, this can cause the circuit breaker in your air compressor system to trip. 

There are many motor windings or any other electrical components inside the motor. Over time, these components can become overheated and fail. This can cause a short in the motor or a number of other intermittent electrical issues.

Bad Pressure Switch

A failed pressure switch is a less likely culprit as to what’s causing your air compressor to trip the circuit breaker, but it’s still worth mentioning.

This can happen because when the pressure inside the tank drops to a certain point, the pressure switch force responds and closes a circuit to make a connection. This signal then turns on power to the compressor motor so it can start.

So, check the following steps to see if your air compressor has a bad pressure switch:

Step 1: Turn off and unplug the air compressor 

Step 2: Purge all the air from the tank

Step 3: Remove the pressure switch cover 

Step 4: Reset the circuit breaker

Step 5: Monitor the the pressure switch to see if there is an electrical ark or any kind of sparking when you try to turn the compressor on

If you see any kind of spark in your air compressors’ pressure switch when you are trying to turn the machine on, then that is a sign that your pressure switch is more than likely the problem. If this is the case for you, then replacing the pressure switch will likely stop your air compressor from tripping the circuit breaker.

Bad Capacitor

If you have a large enough air compressor to need one, your start capacitor could likely be the cause of your breaker tripping. In fact, this is the most common reason for a air compressor circuit breaker to trip. 

Bad Unloader Valve

An air compressor’s unloader valve can fail at times, which can cause the circuit breaker to trip. This is because when the valve stops working, compressed air gets trapped in the cylinder.

This drastically increases the load on the compressor motor when it’s starting. So, this addition can make the motor pull too many amps. When that happens, you guessed it, the breaker trips.

Luckily, it’s super easy to test your air compressor’s unloader valve. Just follow these simple steps:

Step 1: Turn off and unplug the compressor

Step 2: Purge the air tank

Step 3: Plug the compressor back in and turn it on

If your air compressor is now able to start and no longer trips the circuit breaker, then that means your unloader valve is bad.

Will a Bad Compressor Motor Trip A Breaker?

Absolutely. If your compressor motor is seized, locked up, or otherwise ‘bad,’ it will draw too many amps. This will cause the internal circuit breaker to trip.If the circuit breaker did not trip, then it could cause a fire. 

Why Is My Air Compressor Tripping The Breaker As Soon As It Starts

While there are many possible causes for this, it’s most likely due to a bad unloader valve or start up capacitor. These two components are related to the starting of the air compressor, and they are both known to cause the circuit breaker to trip

Testing Air Compressor Capacitors

There are several different ways to test a capacitor and there are many different tools out there to do so. There is, however, a method of testing a capacitor that the average person already has the tools for.

When a capacitor fails, it fails in one of two ways. They either become an open circuit, or a short circuit. When they fail and become a short circuit, they will trip the breaker on your air compressor. If the breaker does not trip, the capacitor can start a fire or even explode.

Capacitor Connection Failure

The easiest capacitor problem that you can notice is a connection failure. All you have to do is take a look at the terminals where the capacitor connects to the board or wiring harness. 

Check to see if those connections are loose, rusty or corroded. Also make note of any discoloration that you may see. If the color of the capacitor pins looks distorted a bit, that could be a sign that it overheated.

Equipment Needed For Testing Air Compressor Capacitors

The only thing you need to check the capacitor in your air compressor is a multimeter and a phillips head screwdriver.

Check Voltage

The first thing to do is to check the voltage of the capacitor. Set your multimeter to DC volts, and if it’s not an auto-ranging model, set it to 200VDC. Turn the compressor on and then immediately back off again. 

Turning it off will more than likely be automatic in your case, seeing as you are having a problem with the circuit breaker tripping. The point of doing this is to make sure the capacitor was attempted to be charged recently. Now that that’s out of the way, you can test the capacitor’s voltage.

You will see a marking on the capacitor indicating which connection is positive and which is negative. To test the capacitor’s voltage, simply connect your multimeter’s black connection to the capacitor’s negative connection, and attach your multimeter’s red connection to the capacitor’s positive connection. 

If you see zero volts on the multimeter, then that means your air compressor capacitor has an open-circuit failure.

If you are getting no voltage on the capacitor, that could be for several different reasons. It doesn’t necessarily mean that your capacitor itself is damaged. So, it’s good to remove it from the circuit to test it on its own.

To do that, make sure there is absolutely no power in the air compressor capacitor. You can do this by touching the terminals together with a screwdriver. After that, remove the capacitor and then set your multimeter to read ohms. 

Connect the multimeter in the same way before, and see what you get on the screen.

Once you do this, the meter should go to zero ohms. After that, swap your probes to the opposite terminals of the capacitor. Now, this charges the capacitor in the opposite way from what you are measuring. So, you should see a negative number on the multimeter for a moment, then it will scale back up to zero and then eventually to infinity.

Repeat Probe Switching

Repeat this process several times. If you are able to get the reading to cycle through the negative and positive ranges in that way, then that means your capacitor is good and the problem lies elsewhere in your air compressor.

Conclusion

A circuit breaker is a safety device that prevents an air compressor from causing a fire in the event of an electrical problem. 

The most common reason why an air compressor keeps tripping the circuit breaker is a failed start capacitor. It could also be something like a clogged or blocked air filter, a clogged compression cylinder, a bad motor, or something as simple as a damaged extension cord. Other things that could cause an air compressor to keep tripping a breaker is a bad unloader valve, or even a problem with the circuit breaker itself. 

We know this issue can be really annoying, so we hope this article helped you resolve any issues that you may be having with your air compressor. Thanks for reading!