How to Test a Circuit Breaker With a Multimeter: 5 Steps


Written by

Thomas Carter



Marcos E. Williamson

how to test a circuit breaker with a multimeter

Circuit breakers are an essential component of an electrical system, protecting against short circuits and electrical overloads. Any faults or malfunctions in the circuit breakers could spell electrical hazards.

It is essential to test circuit breakers periodically to ensure their proper functioning and reliability. One effective way to test an electrical breaker is by using a multimeter, a versatile tool that we think everyone should own.

In this guide, we will provide a step-by-step guide on how to test a circuit breaker with a multimeter. Read on to learn how to identify potential issues and maintain a safe and efficient electrical network for your homes or offices.

Testing a Breaker with a Multimeter: A Step-By-Step Guide

What To Prepare


  • A multimeter
  • A screwdriver
  • Protective Gears (Gloves, goggles, etc.)

Step 1: Turn off the Power


Working with electrical currents can be dangerous, so safety is a top priority when testing circuit breakers. Failure to take proper precautions can result in injury, electrical shock, and damage to your electrical system.

Before testing the circuit breaker, it is essential to turn off the power supply to the circuit. Proceeding the test without power is crucial to avoid any electrical hazards during the testing process.

Step 2: Set the Multimeter to Ohms


Set the multimeter to Ohms. This setting measures the resistance of the circuit breaker. If you do not know how to get to this setting, look for the Omega symbol and dial the knob.

Though there are other settings applicable to testing a circuit breaker, the Ohms setting is by far the best. This mode provides accurate reading to help verify the continuity of the circuit breaker via its resistance reading.

Step 3: Take the Circuit Breaker out of the Panel


Detach the circuit breaker from the electrical panel. This step is necessary to isolate the circuit breaker from the rest of the electrical system. You can enlist the help of a screwdriver.

Step 4: Touch the Multimeter Probes & the Multimeter Terminals

Touch the multimeter probes to the circuit breaker terminals. The red one should touch the power supply terminal. Ensure that both of the probes make a secure connection with the terminals.

Step 5: Get a Reading & Interpret It


Once the probes are in place, the multimeter will display a reading. A reading of zero indicates that the circuit breaker is functioning correctly. A reading other than zero indicates that the circuit breaker is faulty, thus should be replaced.

  • Note: You can use this process to test main breaker, GFCI breaker, DC circuit breaker, breaker fuse, etc.

Other Ways to Diagnose Issues of a Circuit Breaker

  • Mechanical Test: Repeatedly open and close the breaker to check that it closes and opens at the right speed and can function properly.
  • Thermal Test: Put the breaker through temperature rises, steady-state to check its thermal behavior is within the acceptable range.
  • Dielectric Test: Test the breaker’s voltage to check its power and impulse capacity.

Tests & Reading Evaluations

Test Good Bad
Continuity 0 ohms No continuity
Resistance Low High
Voltage Equal to supply value No voltage

Safety Tips for Testing Breakers With a Multimeter


When using a multimeter to test breakers, safety should always be the top priority.

  • Before starting, ensure that the device is properly calibrated and in good working condition.
  • Wear appropriate protective gear, such as insulated gloves and goggles.
  • If a circuit is overloaded (Indicated by an OFF breaker switch usually) or there are any signs of damage or wear on your multimeter or breaker, stop testing immediately and seek professional help.

Remember to never test for voltage without proper precautions, especially with a live circuit as this can lead to electrocution! fd, safely testing breakers with a multimeter will help prevent accidents while ensuring accurate results every time.

Troubleshooting Common Circuit Breaker Problems

1. Common Circuit Breaker Issues


Some common circuit breaker issues include tripping frequently, not tripping at all, or not resetting after tripping. These issues can result from short circuits, overloading, or faulty circuit breakers.

2. Troubleshoot Circuit Breaker Issues Using a Multimeter

To troubleshoot circuit breaker issues with a digital multimeter, you need to follow these steps:

  1. Turn off the power to the circuit breaker you want to troubleshoot.
  2. Set the multimeter to the continuity or ohms setting.
  3. Check for continuity across the circuit breaker terminals.

If you detect an open circuit, it means that the circuit breaker has tripped and needs to be reset or replaced. If the circuit is closed, but the issue still persists, you may need to investigate other components of the circuit.

3. The Signs to Determine If a Breaker is Bad


One common indication that a replacement is necessary is if the breaker trips frequently or fails to trip at all when there is an overload. It may indicate that the breaker has worn out over time or has become damaged.

Additionally, rust, corrosion, or visible signs of damage on the circuit breaker panel could also signify that it needs replacement.

4. How to Replace a Broken Circuit Breaker

Replacing a broken circuit breaker may seem daunting at first, but it is actually a fairly straightforward process.

  1. First, turn off the main power switch and carefully remove the panel cover to access the breakers.
  2. Use a voltage tester to verify that there is no current flowing through the breaker you will be replacing.
  3. Once you have confirmed it is safe to proceed, unclip the old breaker from its housing and remove it from the panel.
  4. Take note of how many wires are connected to it before detaching them one by one and transferring them over to your new circuit breaker.
  5. Then, snap your new circuit breaker into place, reattach any wires in their correct positions, and restore power by turning on the main switch again.
  6. Finally, test out the circuit to ensure everything is functioning properly before closing up the panel cover again.

Voila! You have successfully replaced a broken circuit breaker!

5. Pros & Cons of Using a Multimeter


Using a multimeter for circuit breaker testing has several advantages and disadvantages.

One of the primary benefits is that it allows professionals to quickly determine if a breaker is good, without having to physically open the circuit’s electrical panel or rely on visual inspection alone. This can save time and increase efficiency when troubleshooting electrical issues.

However, there are also some potential drawbacks to using a multimeter.

For example, if the device is not used correctly or calibrated properly, it could provide inaccurate readings that could lead to misdiagnosis or errors in repair work.

In addition, relying too heavily on multimeters may cause technicians to overlook other important indicators of malfunctioning breakers, such as sound or smell.

Frequently Asked Questions (FAQs)


What is the importance of testing a circuit breaker?

Testing your circuit breakers regularly is a vital part of maintaining the safety and performance of your electrical system.

By using a multimeter, you can quickly and easily identify any issues and take corrective action. Remember to always follow safety guidelines and turn off the power before testing your circuit breakers.

Testing circuit breakers is important to ensure that they are functioning correctly and protecting your electrical system from potential hazards.

If a circuit breaker fails to trip when it should, it can lead to electrical fires and other safety hazards. Regular testing can help identify any issues before they become a problem.

Can a breaker go bad without tripping?

Yes. A breaker can be faulty without tripping. It might be bad because of other issues, such as loose or exposed wiring.

How often should I test my circuit breakers?

It is best to check to see if a breaker is bad every 1 to 3 years and conduct a trip test every 3 to 5 years. You should also check the circuit breaker whenever it is near its rated capacity or experiences interrupted current.

How do I know if my multimeter is accurate?

You can test the multimeter by measuring its fuse performance and checking how it reads voltages. You canf also see if your multimeter is properly calibrated. It should be 0 ohms when you touch the black ground point and red lead point at the lowest ohms setting.

Can I test a circuit breaker without a multimeter?

You can look for indications, like constant tripping and frequent mode-shifting. Weird smells and excessive heat are also signs of a faulty circuit breaker.

What else can you test with a multimeter?

Besides the main purpose: test a faulty breaker, you can use a multimeter to check amps and check voltage at the breaker box.

So, for example, you can test a 220 breaker showing signs of damage or measure amps on a 240V circuit.


Testing a circuit breaker with a multimeter is an essential part of maintaining an electrical system. It can help identify issues before they become major problems and ensure the safety of people and property.

By following the steps outlined in this blog post on how to test a circuit breaker with a multimeter, you can test your breakers with confidence and maintain the optimal performance of your electrical system. Remember, always prioritize safety when working with electricity and follow proper safety procedures.

5/5 - (2 votes)