Never test a fuse on equipment that is still on. All of these fuses can be installed and removed by using a special tool, a fuse puller. How To Test A Fuse Using A Multimeter? The first test is to do a visual check of the fuse. The fuse box is typically mounted under the dashboard on the driver's side, or near the glove box on the passenger side. If you want to use the meter as an ammeter, keep reading! 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. They come in 15, 20, and 30-amp sizes and are... Cartridge Fuses. 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. It is usually grey in color and mounted near the outdoor AC unit. Turn the meter to ohms, then touch the positive and negative leads together and check the reading. What do I do if the reading is 00.00 when I touch the leads to the ends of the fuse or together? It won’t burn off … They have metal contact or terminal points on either end and consist primarily of a tube that contains the wire. If it is, then the fuse works properly. We use cookies to make wikiHow great. Learn what each of these fuses is and how to test each of these fuses below. ", "Found out that the door was not closing properly, no electrical/electronic was burnt. you will see a fuse usually located in the Ac input area or power supply section. These fuses are used in fuse panels and disconnects for amperages over 30 amps. They vaguely resemble the plug of a power cord, with two metal prongs emanating from a plastic housing that contains the wire. If the fuse is good, the test light will light up on both sides of the fuse. The rating ensures that the current can pass through the wiring safely. Testing fuses can be done using a multimeter, and doing so is both fast and easy to learn. Remove the Plug Fuse. There is no polarity so you can use any lead for either fuse cap. 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. Never replace a blown or suspect fuse with one of a higher rating. 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. When a fuse is broken, what does it read on a multimeter? Open the door on the fuse panel and look for the fuse you want to test. ", "It was precise and to the point. Get daily tips and tricks for making your best home. 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. Any reading other than OL or a blank screen tells you the fuse is good. It's big brother, the knife-blade cartridge fuse, is similarly shaped with blades on each end. When a fuse is broken, it reads the circuit is not complete, so it reads an open line. Instructions Identify the Plug Fuse. 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. This is because the blown fuse allows there to be a voltage differential between the two sides. Yes, you can, provided that the source is cut-off from the fuse itself. Look closely at each fuse. 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. If the fuse is bad, only one side will illuminate the test light. Set the multimeter. If you really can’t stand to see another ad again, then please consider supporting our work with a contribution to wikiHow. It mimics the shape of the fuse and snaps over the fuse for easy removal. Cartridge fuses come in a cylindrical shape and have contacts points at each end. Most plugs will have a fuse inside them. The Ferrule-type fuses are rated up to and including 60 amps. A charred wire or defective device in the circuit will probably need replacement. The Ferrule-type cartridge fuse is generally used for the main feeder and range protection. Blade fuses plug conveniently into banks, and relatively little space is required to house a large number of them together. The difference is that they protect circuits above 60 amps up to 600 amps. First, you need to know what fuses are and just exactly what they are designed to do. It is easier to test fuses than it is to test other electrical equipment. They control the amount of amperage to the circuit it connects to. All fuses have two terminals, positive and negative one. Can I not remove the fuse from a control board? 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. If the reading is close to the one you got when you touched the positive and negative leads, the fuse is fine. Once you have located the poles, take the probes and place them on the negative and positive sides of the... Additional check. Plug fuses control 120-volt circuits that normally feed lighting and receptacle loads throughout your home. If the fuse turns out to be good, you can use a circuit tester to trace the wiring path and find out what's gone wrong. Household installations these days shouldn't really be protected by just fuses. 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