It is usually made out of plastic. All of these fuses can be installed and removed by using a special tool, a fuse puller. With the main power still off, unscrew the blown fuse and remove it. The newer style, Edison-based, have a plastic thread with a spring-type contact and a center contact. Exactly what I wanted. Manually test the breaker first. Touch the probes to both end of the fuse. When testing resistance in a circuit, the meter will transmit a small quantity of electricity from its own battery and then measure the amount that passes through the circuit or object. L ocated inside or outside of your home is a circuit breaker panel (sometimes called a fuse box) that contains circuit breakers for each of the circuits in your home. How To Check a Fuse Box How To Replace a Fuse. The rating ensures that the current can pass through the wiring safely. Touch the metal caps at each end of the fuse with the metal tips of the testing leads. This article was co-authored by Ricardo Mitchell. Flip it back and forth, and if it does not stay in the "on" position, the … Without a fuse or circuit breaker with this specific rating, there would be nothing to protect the wiring, devices, or the operator running things like power tools. Evaluating Electrical Loads Place the fuse on a non-conducting surface such as wood, laminate or plastic. Again, you should see the … Step 1 Open the panel on the front of the fuse box by prying back its latch with your hand. When the circuit in your home quits working, and you suspect that it is likely a blown fuse, you can test that theory by using a multi-meter for testing fuses. Before you test a fuse with a multimeter, turn off the equipment and remove the fuse by pulling it straight out of its slot. They have metal contact or terminal points on either end and consist primarily of a tube that contains the wire. Look closely at each fuse. To double-check that diagnosis, try disconnecting some of the electrical loads on that circuit, reset the breaker and wait a few minutes. Normally, range feeds will have 50-amp fuses, and the main fuses are generally 60 amps, being more common in older homes. % of people told us that this article helped them. If the fuse can be removed from the circuit, then the easiest way to determine if it has blown is a continuity test. Step 5: If a fuse continues to blow after it has been re-­wired, check for faulty appliances by unplugged all appliances and plugging them in one by one after replacing the fuse. Introducing "One Thing": A New Video Series. Then put the probes on either side of the fuse and check if the reading is similar. We can check the fuse visually to see if it's broken or we can do an electrical test on the fuse using a multimeter to see if it's good or blown. Step 2. If you want to use the meter as an ammeter, keep reading! Next, touch one lead to the center point of the fuse, and touch the other lead to the metal threads on the side of the fuse. Next, put one lead on each end of the fuse and check the reading. If the circuit doesn’t blow, turn the lights back on and plug in appliances one by one to check for the overload or short circuit. Thanks! If the positive path is intact, you can also use the test light to check the grounding points of the circuit. With the ignition switch in the ON position, touch or clamp the black test lead to a good known ground. Here is the part on how to test a fuse. Fuses take time to heat up and blow, and when that happens, you have to purchase and install replacements. The difference is that they protect circuits above 60 amps up to 600 amps. Thanks a million. If the fuse is bad, only one side will illuminate the test light. Breaker Tripping Frequently or Not Staying Reset. Always replace a fuse with the same rating as (or a lower rating than) the old one. Testing the fuse using a multimeter Locate the terminals. About the Book Author Gary and Peg Hedstrom are self-taught repair masters with experience in carpentry, plumbing, appliance repair, and more. Fuses provide protection against overloading, short circuits, or device load, etc. Approved. If the fuse is blown, the meter will not read anything at all, or the meter may say “Open Loop” or "OL." If too much power runs through the fuse, it will "burn out," quite literally, and open the circuit, preventing the current from flowing through the circuit. This article has 11 testimonials from our readers, earning it our reader-approved status. Other components in your car or home involve complex wiring systems that run on for some length. To test a fuse simply touch one lead to each of the electrical contacts on the fuse; if the light bulb lights up the fuse is good. On the end cap of a blade fuse, you'll see two exposed areas of metal designed for testing. You can use it to check any positive circuit, from your cigarette lighter to your headlights and taillights. L ocated inside or outside of your home is a fuse box that contains a fuse for each of your home's circuits. Sometimes these fuses require testing to check that they are still in good working order. Open the door on the fuse panel and look for the fuse you want to test. Plug fuses are common fuses used in a home's fuse panel. Now, you need to locate the blown fuse. Many types of fuses allow for visual confirmation that the fuse is still functional. Set the multimeter. It is easier to test fuses than it is to test other electrical equipment. When this happens, no current can flow, and the circuit is disconnected from the power supply. This protects against short circuits and overloads that may damage electrical wiring and cause house fires. Cartridge fuses are cylindrical and have the contact points at either end. Step 1. If the multimeter reads "Open" or "Not complete," it means the fuse is broken. Please help us continue to provide you with our trusted how-to guides and videos for free by whitelisting wikiHow on your ad blocker. Ricardo has over 10 years of electrical and construction experience and his partners have over 30 years of relevant experience. They come in 15, 20, and 30-amp sizes and are screwed into the electrical panel. This article has been viewed 712,848 times. 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. There are 2 tests we can use to check to see a fuse is good or blown. 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. When a fuse is broken, it reads the circuit is not complete, so it reads an open line. ", "Found out that the door was not closing properly, no electrical/electronic was burnt. Now that we know the basic terminology, we finally come to the steps to test a fuse using a multimeter. Using a test light to check a fuse that appears not to work but changing the connection to a positive source touching the same fuse and the test light goes on. In addition, most car parts can only be tested at repair shops, and to do so will usually cost quite a lot of money. Use a pair of pliers, if needed; popped fuses can melt into the socket. Consider having an old fuse installation upgraded to modern standards. These fuses supply the branch circuits in your home to run lights, outlets, and appliances. Plug fuses screw in and come in 15, 20, and 30-amp ratings. What should I do if I have a circuit that reads 0 ohms but continually blows fuses? The meter will read OL if the fuse is bad. They come in 15, 20, and 30-amp sizes and are... Cartridge Fuses. Ensure to make good contact by touching a clean metal surface on each cap. There are thousands of different types of fuses, but they all essentially perform the same function. 1. Fuses come in different styles, cartridge, and screw-in. A ceramic fuse, however, shows no damage upon visual inspection. This will measure the resistance of the fuse link, if intact. Understand fuses. By setting the selector switch to ohms and setting it on a lower range, you can test the resistance between the two points of the fuse. By using our site, you agree to our. Touch the red test lead to the first metal square, then to the other. Testing fuses with a multimeter is comparatively simple to do, and the equipment involved is cheap and easy to operate. This article really helped me on how to, "This article instantly gave me the info I needed with the minimum of extraneous detail. If it doesn’t trip again then the problem is too many things on one circuit, or a single appliance—like a portable space heater—that draws more current than the rating of the breaker. When working with anything electrical, shut the power off to the device that you'll be working on and check with a tester to make sure it is not live. The Spruce uses cookies to provide you with a great user experience. Turn the meter to ohms, then touch the positive and negative leads together and check the reading. If you get no reading or “OL”, then the fuse has blown. Step 3: If the wire is broken, replace it with fuse wire of the same amp rating. Well, your circuit is putting out too much power for your multimeter to read. 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. I would recommend lowering your power source's output through resistors or adding additional places for electricity to flow. So if you get 00.00 your fuse is good. Open the door of the service panel and see if a circuit breaker is tripped (or a fuse is blown). You've heard the term blown fuses, but what is this exactly? Timothy Thiele is an electrician who advises residential DIYers on how to make home installation projects safe and easy. You should see a voltage reading in the 12-14 volts range. Open the box door and turn on the flashlight to inspect the fuses. If so, reset the breaker (or replace the fuse). If a fuse blows does that mean there's problem with the amp? The best way to test for a blown fuse is by using a voltmeter. If the fuse is good, the test light will light up on both sides of the fuse. In the case of a short or overload, causing too much current to flow, the ribbon will melt and open the circuit. This is because the blown fuse allows there to be a voltage differential between the two sides. By using this service, some information may be shared with YouTube. ", "I wasn't sure how to test my household's cylindrical fuses, you showed my how. Regarding car fuses, most cars use a colored 'blade' type fuse, and looking at the top of the fuse in situ in the fuse box will show that the metal strip that runs along the visible top of the fuse will either be intact (fuse good) or broken (fuse blown). Get a voltage tester that’s rated for up to 500 volts. They have a fuse link connected to the two ends and are rated for 240-volt circuits and protect the circuit from over-current. test a fuse and hopefully save me hundreds of dollars in repairs by just replacing a blown fuse. Watch for … Step 4: Reinstall the fuse and turn the main switch back on. This article has been viewed 712,848 times. Plug fuses come in a screw-type configuration. Last Updated: November 18, 2020 Blade fuses plug conveniently into banks, and relatively little space is required to house a large number of them together. Perform a quick test of the meter to ensure it’s functioning properly by touching the leads together until you hear a … The older type fuses have a brass screw thread on the side and a center contact point. The blade fuse is a common type of automotive fuse that has come into use in the last 20-30 years. Most plugs will have a fuse inside them. Previously, most vehicles also contained small glass cartridge fuses. Some homes have more than one circuit breaker panel, there may be a main panel plus one or more sub panels in other locations. Remove the Plug Fuse. Instructions Identify the Plug Fuse. The cartridge fuse is a cylindrical fuse that has been common in a wide variety of devices for many years, from homes to small electronic devices. By signing up you are agreeing to receive emails according to our privacy policy. They control the amount of amperage to the circuit it connects to. A good fuse would have shown zero volts. Never replace a blown or suspect fuse with one of a higher rating. Cartridge fuses come in a cylindrical shape and have contacts points at each end. ", "It was precise and to the point. If you want to measure the ohms, use the multimeter setting that has the omega symbol (Ω). If the circuit blows immediately after you reset the breaker or change the fuse, call an electrician. Never test a fuse on equipment that is still on. If the reading is close to the one you got when you touched the positive and negative leads, the fuse is fine. If the fuse has a broken or melted connector, it is blown. Plug fuses control 120-volt circuits that normally feed lighting and receptacle loads throughout your home. The Edison-type base has an advantage over the older style. 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. These testers are available at most home improvement or electronic supply stores. Your home's electrical wiring must be protected from short circuits and circuit overloads. Turn off the main power switch to disconnect power to the fuse box. How To Test A Fuse Using A Multimeter? All fuses have two terminals, positive and negative one. One place to check is at the connections in the fuse boxes, using a 12-volt test light. wikiHow marks an article as reader-approved once it receives enough positive feedback. What do I do if the reading is 00.00 when I touch the leads to the ends of the fuse or together? A homeowner can determine if a glass fuse in blown by performing a visual inspection and looking for a break in the thin wire and a brown discoloration in the center of the fuse. Twist them counterclockwise to remove them from the socket. A fuse provides protection for each of your electrical circuits by stopping the flow of current if an overload or fault occurs. It mimics the shape of the fuse and snaps over the fuse for easy removal. However, there are many settings on a multimeter to measure amperage, voltage and resistance in several different ranges. First, you need to know what fuses are and just exactly what they are designed to do. Fuses are really just wires that are designed not to last, but their purpose is to prevent damage to more valuable electrical equipment or prevent fires (especially in homes) caused by power surges. Cars and older homes that don’t use modern circuit breakers use fuses to prevent damage from electrical surges. How to Reset a Circuit Breaker. Before you test the fuse, you need to know what it is about. Put on a pair of rubber-soled shoes and make sure the area around the circuit box is dry. Grab a multimeter and select the continuity or resistance setting. you will see a fuse usually located in the Ac input area or power supply section. If the translucent area is blackened, it is. Learn what each of these fuses is and how to test each of these fuses below. The Ferrule-type fuses are rated up to and including 60 amps. Testing a Fuse With a Multimeter. To verify that you have a blown fuse on hand, the first step is to locate the disconnect box. It only allows the appropriately sized fuse to be installed, unlike the old style that you could install a 30-amp fuse in a 15-amp socket. We know ads can be annoying, but they’re what allow us to make all of wikiHow available for free. ", "What volt meter setting to touch both leads was helpful.". Include your email address to get a message when this question is answered. The Ferrule-type cartridge fuse is generally used for the main feeder and range protection. Thanks to all authors for creating a page that has been read 712,848 times. Plug fuses have a metal alloy ribbon inside that carries the current of the circuit. 2. How to Test Fuses Using a Multi-meter Plug Fuses. If you’re using a digital multimeter set to measure resistance, touch the probes together to get an initial reading. By using The Spruce, you accept our, How to Troubleshoot and Fix Holiday Christmas Lights, How to Determine the Size of Your Main Electrical Service, 4 Reasons Why Circuit Breakers Trip and Fuses Blow, Using a Neon Circuit Tester to Check Receptacles for Proper Grounding, How Electrical Service Panels Have Evolved, How to Turn Off the Power at Your Home's Breaker Box or Fuse Box, Calculating Electrical Load Capacity for a Home. Inspect the socket, which is very similar to a lamp or light socket and locate the single standard screw in the very bottom. 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