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Electrical Safety
How to Tell if a Circuit Breaker Is Bad Download ArticleExplore this Article parts 1 Testing the Breaker with a Multimeter 2 Replacing a Defective Breaker Other Sections Expert Q&A Tips and Warnings Things You'll Need Related Articles References Article Summary Co-authored by Ricardo Mitchell and Hunter Rising
Last Updated: August 11, 2025 Fact Checked
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This article was co-authored by Ricardo Mitchell and by wikiHow staff writer, Hunter Rising. Ricardo Mitchell is the CEO of CN Coterie, a fully licensed and insured Lead EPA (Environmental Protection Agency) Certified construction company located in Manhattan, New York. CN Coterie specializes in full home renovation, electrical, plumbing, carpentry, cabinetry, furniture restoration, OATH/ECB (Office of Administrative Trials and Hearings/Environmental Control Board) violations removal, and DOB (Department of Buildings) violations removal. Ricardo has over 10 years of electrical and construction experience and his partners have over 30 years of relevant experience. There are 14 references cited in this article, which can be found at the bottom of the page. This article has been fact-checked, ensuring the accuracy of any cited facts and confirming the authority of its sources. This article has been viewed 526,969 times.
If you have a circuit that keeps tripping whenever you use electronics, it may be time to check if your breakers need to be replaced. Though they have a life expectancy of 30 to 40 years, breakers will eventually die and trip your circuits.[1]X Trustworthy Source US Occupational Safety and Health AdministrationU.S. government agency responsible for setting and enforcing workplace safety standards Go to source By opening your panel and using a digital multimeter to check the voltage levels, you can easily see if your breakers are the problem. Just be careful when you work with live electricity!
Steps
Part 1 Part 1 of 2:
Testing the Breaker with a Multimeter
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1 Unplug or turn off all devices connected to the breaker. Getting all of the electronics off of the circuit will prevent it from surging. If you have labels on your breaker box for what each switch controls, take the time to check what needs to be unplugged.[2]XResearch source
If you're not sure what each breaker controls, unplug the electronics in the area where the breaker tripped before working on it.
2 Unscrew the panel from the breaker box and set it aside. Use either a flathead or Phillips-head screwdriver depending on what screws are on the panel. There will at least be 2 screws, but there may be more. Set the screws aside in a safe place so you know where they are when you need to put the panel back on.[3]XResearch source
As you remove the last screw, hold the panel up with your non-dominant hand and slowly remove the panel cover.
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3 Turn on your digital multimeter. A multimeter is a machine that tests the voltage or current through electric components. Plug the black wire into the port labeled “COM” or “Common,” and plug the red wire into the port labeled with the letter V and the horseshoe symbol (Ω). This will ensure you're measuring the voltage of the breaker.[4]XResearch source
Multimeters can be purchased at your local hardware store or online.
Check the casing on the wires to make sure they have no cracks or damage. Electricity will travel through the cracks and possibly cause electrocution. If you see any damage, use a different multimeter.
4 Hold the red probe against the screw on the breaker you're testing. Hold the probe, the exposed metal end of the wire, so you aren't touching the exposed metal. Touch the end of the probe to the screw on the left or right side of the breaker.[5]XResearch source
5 Put the black probe against the neutral bar. Look for where the white wires leading from your breakers attach. Place the end of the black probe anywhere on the neutral bar to complete the circuit on your multimeter.[6]XResearch source
Do not touch the neutral bar with bare skin since it could cause electrocution.
If you have a double pole breaker, place the end of the black probe onto the second terminal screw of your breaker to get the correct reading.[7]XResearch source
6 Compare the reading on the meter to the breaker requirements. If you have a single pole breaker, check to see if the reading is around 120 V. It may be slightly above or below, but this is fine. If the breaker reads 0, it needs to be replaced. If you have a double pole breaker, make sure the reading is between 220-250 V. A faulty double pole breaker will read at 120 V, meaning it's only operating at half power.[8]XResearch source
The voltage of your circuit breaker depends on the size of the wire that comes into the circuit. For instance, if you have a number 10 wire, that's equivalent to 30 amps.[9]X Expert Source Ricardo MitchellElectrician & Construction Professional, CN CoterieExpert Interview
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Replacing a Defective Breaker
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1 Find a replacement breaker with the same voltage. Look in the electrical section at your local hardware store for breakers that are the same size as the ones you're replacing. Single and double pole breakers typically range from around $5 to $10 USD.[10]XResearch source
2 Turn off the individual breaker you need to replace. Push the switch into the off position before you start working on it. This prevents the current from traveling through the wires attached to that specific breaker.[11]XResearch source
If your breaker has a main circuit switch on the top or bottom, turn it off to completely shut off the electricity. If you only do this for a few minutes while replacing the breaker, foods in the fridge and freezer will keep.
3 Loosen the terminal screw and pull the wires out. Use the appropriate screwdriver for the type of screw holding your wires down. Turn the screw until the wires start to feel loose. Use a pair of needle-nose pliers to pull the exposed wires out from the terminal, making sure they don't touch any other wires or breakers.[12]XResearch source
Use tools with a rubber insulated handle to lower the risk of electrocution or shock.
4 Grab the front part of the breaker and pull out the old breaker. Place 2 or 3 of your fingers on the side of the breaker opposite of the terminals and place your thumb near the terminals. Pull up on the side with your fingers to pop the clips out of place and remove the breaker.[13]XResearch source
Do not touch the metal bars in the back of your circuit box if you did not shut off the main power. They are live and could cause electrocution.
5 Slide the clips of the new breaker in place and push it in. Put the side with the terminals into place first so the clips latch onto the bar. Push the opposite side down to lock the breaker into place.[14]XResearch source
Make sure your new breaker is in the off position before placing them in the box.
6 Use needle-nose pliers to hold the wires while you tighten the terminal screw. Hold the insulated part of the wire with the end of your pliers. Put the exposed end into the new terminal and use your other hand to screw it on. Make sure the screw is snug but not overly tight, or else you could strip it.[15]XResearch source
7 Turn your breaker on and reattach the panel to the breaker box. Flip the breaker switch to the on position and screw the panel back on to hide the wires again. Close the breaker box to wrap up.[16]XResearch source
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Expert Q&A
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Question How do I figure out what the voltage of my circuit breaker is supposed to be? Ricardo Mitchell Electrician & Construction Professional, CN Coterie Ricardo Mitchell is the CEO of CN Coterie, a fully licensed and insured Lead EPA (Environmental Protection Agency) Certified construction company located in Manhattan, New York. CN Coterie specializes in full home renovation, electrical, plumbing, carpentry, cabinetry, furniture restoration, OATH/ECB (Office of Administrative Trials and Hearings/Environmental Control Board) violations removal, and DOB (Department of Buildings) violations removal. Ricardo has over 10 years of electrical and construction experience and his partners have over 30 years of relevant experience. Ricardo Mitchell Electrician & Construction Professional, CN Coterie Expert Answer That depends on the size of the wire that comes into the circuit. If you have a number 10 wire, for instance, that's equivalent to 30 amps. Thanks! We're glad this was helpful.Thank you for your feedback. If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow Yes No Not Helpful 26 Helpful 6
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Tips
If you don't feel comfortable working inside your breaker box, hire an electrician to take a look and replace any breakers if necessary. Thanks Helpful 0 Not Helpful 0
Submit a Tip All tip submissions are carefully reviewed before being published Name Please provide your name and last initial Submit Thanks for submitting a tip for review! Advertisement
Warnings
If your breakers still do not work, you may have an issue with your wiring. Call a professional electrician to diagnose the problem. Thanks Helpful 12 Not Helpful 2
Be careful while working inside your breaker box since they are live and could cause electrocution. Thanks Helpful 5 Not Helpful 2
Never use a multimeter if the lining on the probes is cracked or damaged. This could cause electrocution. Thanks Helpful 4 Not Helpful 4
Make sure you always replace a breaker with one that has the same voltage. Thanks Helpful 6 Not Helpful 8
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Things You'll Need
Testing the Breaker with a Multimeter
Screwdriver
Digital multimeter
Replacing a Defective Breaker
New breaker with the same voltage
Screwdriver
Needle-nose pliers
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Co-authored by: Ricardo Mitchell Electrician & Construction Professional, CN Coterie This article was co-authored by Ricardo Mitchell and by wikiHow staff writer, Hunter Rising. Ricardo Mitchell is the CEO of CN Coterie, a fully licensed and insured Lead EPA (Environmental Protection Agency) Certified construction company located in Manhattan, New York. CN Coterie specializes in full home renovation, electrical, plumbing, carpentry, cabinetry, furniture restoration, OATH/ECB (Office of Administrative Trials and Hearings/Environmental Control Board) violations removal, and DOB (Department of Buildings) violations removal. Ricardo has over 10 years of electrical and construction experience and his partners have over 30 years of relevant experience. This article has been viewed 526,969 times. 82 votes - 87% Co-authors: 10Updated: August 11, 2025 Views: 526,969 Categories: Electrical SafetyArticle SummaryX
To tell if a circuit breaker is bad, start by unplugging or turning off all devices that are connected to the breaker. Then, unscrew the panel from the breaker box and turn on a digital multimeter, which is a small device used for testing voltage that you can find at your local hardware store. Next, hold the red probe on the multimeter to the screw on the breaker and put the black probe against the neutral bar. If the breaker reads "0" on the multimeter, it needs to be replaced. To learn how to replace a circuit breaker, scroll down!Did this summary help you?YesNo
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Reader Success Stories
Sandy Johnson
Jan 21, 2018
"Needed to replace an outlet so I shut off the breaker, replaced it, then went in to flip the breaker back on. It was loose and there was hardly a click at all, and my lights never came on. I Googled it and came to this article, and it explained it perfectly."..." more
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Yes No Advertisement Cookies make wikiHow better. By continuing to use our site, you agree to our cookie policy. Co-authored by: Ricardo Mitchell Electrician & Construction Professional, CN Coterie Co-authors: 10Updated: August 11, 2025 Views: 526,96987% of readers found this article helpful. 82 votes - 87% Click a star to add your vote
Sandy Johnson
Jan 21, 2018
"Needed to replace an outlet so I shut off the breaker, replaced it, then went in to flip the breaker back on. It was loose and there was hardly a click at all, and my lights never came on. I Googled it and came to this article, and it explained it perfectly."..." more
Steve P.
Dec 17, 2024
"I needed to brush up on the procedure for testing and replacing a breaker in a 200-amp breaker box. The instructions and procedures were thorough and accurate, and the language was clear. I found it very helpful."..." more
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Aug 20, 2017
"Don't know too much about electrical stuff. This page was very informative to me. Really helped me understand the situation."..." more
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Download Article Explore this Article parts 1 Testing the Breaker with a Multimeter 2 Replacing a Defective Breaker Other Sections Expert Q&A Tips and Warnings Things You'll Need Related Articles References Article Summary Co-authored by Ricardo Mitchell and Hunter Rising 
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Co-authored by: Ricardo Mitchell Electrician & Construction Professional, CN Coterie This article was co-authored by Ricardo Mitchell and by wikiHow staff writer, Hunter Rising. Ricardo Mitchell is the CEO of CN Coterie, a fully licensed and insured Lead EPA (Environmental Protection Agency) Certified construction company located in Manhattan, New York. CN Coterie specializes in full home renovation, electrical, plumbing, carpentry, cabinetry, furniture restoration, OATH/ECB (Office of Administrative Trials and Hearings/Environmental Control Board) violations removal, and DOB (Department of Buildings) violations removal. Ricardo has over 10 years of electrical and construction experience and his partners have over 30 years of relevant experience. This article has been viewed 526,969 times. 82 votes - 87% Co-authors: 10 Updated: August 11, 2025 Views: 526,969 Categories: Electrical Safety Article SummaryX
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1 Unplug or turn off all devices connected to the breaker. Getting all of the electronics off of the circuit will prevent it from surging. If you have labels on your breaker box for what each switch controls, take the time to check what needs to be unplugged.[2] 
2 Unscrew the panel from the breaker box and set it aside. Use either a flathead or Phillips-head screwdriver depending on what screws are on the panel. There will at least be 2 screws, but there may be more. Set the screws aside in a safe place so you know where they are when you need to put the panel back on.[3] 
3 Turn on your digital multimeter. A multimeter is a machine that tests the voltage or current through electric components. Plug the black wire into the port labeled “COM” or “Common,” and plug the red wire into the port labeled with the letter V and the horseshoe symbol (Ω). This will ensure you're measuring the voltage of the breaker.[4] 
4 Hold the red probe against the screw on the breaker you're testing. Hold the probe, the exposed metal end of the wire, so you aren't touching the exposed metal. Touch the end of the probe to the screw on the left or right side of the breaker.[5] 
5 Put the black probe against the neutral bar. Look for where the white wires leading from your breakers attach. Place the end of the black probe anywhere on the neutral bar to complete the circuit on your multimeter.[6] 
6 Compare the reading on the meter to the breaker requirements. If you have a single pole breaker, check to see if the reading is around 120 V. It may be slightly above or below, but this is fine. If the breaker reads 0, it needs to be replaced. If you have a double pole breaker, make sure the reading is between 220-250 V. A faulty double pole breaker will read at 120 V, meaning it's only operating at half power.[8] 
1 Find a replacement breaker with the same voltage. Look in the electrical section at your local hardware store for breakers that are the same size as the ones you're replacing. Single and double pole breakers typically range from around $5 to $10 USD.[10] 
2 Turn off the individual breaker you need to replace. Push the switch into the off position before you start working on it. This prevents the current from traveling through the wires attached to that specific breaker.[11] 
3 Loosen the terminal screw and pull the wires out. Use the appropriate screwdriver for the type of screw holding your wires down. Turn the screw until the wires start to feel loose. Use a pair of needle-nose pliers to pull the exposed wires out from the terminal, making sure they don't touch any other wires or breakers.[12] 
4 Grab the front part of the breaker and pull out the old breaker. Place 2 or 3 of your fingers on the side of the breaker opposite of the terminals and place your thumb near the terminals. Pull up on the side with your fingers to pop the clips out of place and remove the breaker.[13] 
5 Slide the clips of the new breaker in place and push it in. Put the side with the terminals into place first so the clips latch onto the bar. Push the opposite side down to lock the breaker into place.[14] 
6 Use needle-nose pliers to hold the wires while you tighten the terminal screw. Hold the insulated part of the wire with the end of your pliers. Put the exposed end into the new terminal and use your other hand to screw it on. Make sure the screw is snug but not overly tight, or else you could strip it.[15] 
7 Turn your breaker on and reattach the panel to the breaker box. Flip the breaker switch to the on position and screw the panel back on to hide the wires again. Close the breaker box to wrap up.[16] Advertisement 
Ricardo Mitchell Electrician & Construction Professional, CN Coterie Ricardo Mitchell is the CEO of CN Coterie, a fully licensed and insured Lead EPA (Environmental Protection Agency) Certified construction company located in Manhattan, New York. CN Coterie specializes in full home renovation, electrical, plumbing, carpentry, cabinetry, furniture restoration, OATH/ECB (Office of Administrative Trials and Hearings/Environmental Control Board) violations removal, and DOB (Department of Buildings) violations removal. Ricardo has over 10 years of electrical and construction experience and his partners have over 30 years of relevant experience.