How to Test a Circuit Breaker with a Multimeter (7-Step Guide)

Having a broken circuit breaker can cause a lot of issues for your home. Having said that, today, we are going to talk about how to test a circuit breaker with a multimeter.

To check a circuit breaker’s condition (good or bad), we can perform a voltage test using a digital multimeter. We can check the voltage difference between the breaker’s terminal screw and the ground screw.

This method is one of the effective processes for circuit breaker testing so, let’s get started.

7 Step Guide on How to Test a Circuit Breaker with a Multimeter

First, you will need some tools. So, make sure to get them ready before starting the testing.

Tools Needed

Step 1 – Take Some Time to Ensure Safety

First, make sure all the areas on the electrical panel are dry. Also, mop up groundwater if there is any. All of the water should be removed from the area before opening the panel.

Step 2 – Pick a Circuit Breaker

Now open the electrical panel using a screwdriver. There should be at least two screws. After removing the screws, keep them in a safe place because you will need them later to put the electrical panel back on. Then pick a breaker for the test circuit breaker process. 

Step 3 – Turn Off the Connections

After picking a circuit breaker, turn off all the appliances and lights powered by that circuit breaker.

Step 4 – Set up the Multimeter

As we mentioned earlier in the article, we will measure voltage in this process. So, you need to set up the multimeter for that.

  1. Plug the black probe to the COM, aka Common port.
  2. Plug the red probe into the port that displays the letter V and Ω symbol.

Note: Above two steps will set up the multimeter to voltage mode. When using the multimeter, make sure not to use damaged or cracked probes because electricity can travel through the cracks and might electrocute you.

Step 5 – Use the Two Probes 

Then, hold the red probe on the terminal screw of the circuit breaker. Also, hold the black probe on the ground screw. You should not touch any of these screws with bare skin and always hold the multimeter from its insulation covers. (1)

Step 6 – Check the Reading

Now you can check the voltage on the multimeter. Depending on the circuit breaker you picked, you might get various voltages. For instance, if you test a single-pole breaker, you will get a 120V. The reading can go low or higher slightly. Also, this means the circuit breaker is working.

On the other hand, if you test a double pole breaker, you will get a reading between 220-250V. This means the double pole breaker is working properly.

Step 7 – Identifying Faulty Breakers

If a single-pole breaker does not work properly, you will get a zero voltage reading on the multimeter.

On the other hand, a faulty double pole breaker will show a 120V reading

So, identify both of the above situations correctly and replace the faulty circuit breakers.

How to Replace a Broken Circuit Breaker?

After testing, if you encounter circuit breaker problems, it might be time for a replacement.

In this section, we will give you a step-by-step guide on how the circuit breaker replacement works.

Step 1 – Find a Matching Replacement Breaker

First, you might need to visit your local hardware store. So, go to the hardware store and find the exact sized circuit breaker that you need to replace. It should have the same voltage as the broken one.

Step 2 – Turn Off the Breaker 

You should then turn off the faulty breaker. Never try to remove the breaker from the panel board while it is still ON. You might get electrocuted.

Step 3 – Loosen the Screw 

After that, use a screwdriver to loosen the screws that are holding the wires. Pull out the wires completely.

Step 4 – Pull out the Old Breaker

Use your fingers to pop out the clips that hold the faulty circuit breaker. Then carefully pull out the old circuit breaker.

Note: Do not contact the metal bars located in the circuit box’s back. If you have already turned off the power, there is nothing to worry about. Otherwise, these bars can electrocute you. (2)

Step 5 – Install the New Breaker

Now gently push the new circuit breaker into the freed space. If you do it properly, you will hear the clips latching with the bar.

Step 6 – Tighten the Wires

Place the wires into the new terminals. Use the screwdriver to tighten the screws. 

Step 7 – Reattach the Circuit Breaker Panel

Position the panel correctly and tighten the screws using a screwdriver. Also, even after the new installation, the condition of the electric circuit breaker highly depends on one factor; circuit breaker maintenance.

Is It Possible for a Circuit Breaker to Fail without Tripping?

When the circuit breaker trips that means a bad circuit breaker or a short circuit. Therefore, you should understand tripped circuit breaker is a decisive indication of a broken circuit breaker. However, a circuit breaker can fail without tripping too. Use a multimeter or a circuit breaker tester to identify the reason correctly.

Wrapping Up

We hope that, with this article, you were able to get a good idea of how to test circuit breakers. Now you have the knowledge needed to initiate a breaker test at your home.






References
(1) skin – https://www.bhg.com/home-improvement/exteriors/curb-appeal/house-styles/
(2) electricute – https://www.healthline.com/health/electric-shock

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About Sam Orlovsky

b1d87d2ee85af3e51479df87928bdc88?s=90&d=mm&r=gI realized early on carpentry was a huge passion for me and I’ve stayed in the industry for over 20 years now. This gives me a unique ability to really be able to tell you what the best tools and recommendations are. I’m not only a carpenter but I also like machinery and anything to do with electrics. One of my career paths starting off was as an apprentice electrician so I also have a lot of experience with electrical products and anything related.