How to Test a Fuse with a Multimeter
Two meter tests for home fuses, plus the fuses inside your meter.
Compiled by DIY Repair Guide · reviewed 2026-09-14 ·how we research these
To test a fuse with a multimeter, turn the power off, take the fuse out of its holder, and set the meter to continuity or resistance mode. Touch one probe to each end cap of the fuse. A continuous beep or a resistance reading of zero ohms or close to it means the fuse is good. No beep or a reading of over limit (OL) means the fuse is blown and must be replaced.
Before You Touch the Fuse
Turn off all power to the circuit before you remove any fuse. Per Fluke's fuse testing guidance, ensure the circuit is fully powered off and disconnected from any live power source before testing. The Fluke 15B/17B user manual warns to disconnect circuit power and discharge all high-voltage capacitors before testing resistance or continuity.
In home electrical panels, the U.S. Consumer Product Safety Commission (CPSC) notes that you will encounter Edison-base plug fuses, S-type plug fuses with S-type socket inserts, and cartridge fuses housed in pull-out fuse blocks. In electronics, appliances, and vehicles, you will commonly find glass tube fuses, ceramic fuses, and plastic blade fuses. Always shut off the main panel power before unscrewing a plug fuse, and leave main cartridge fuses to a licensed electrician.
Before setting up your meter, look at the metal rim or end cap of the fuse to find its rated amperage. The CPSC points out that in older 60-ampere residential panels, most branch fuses should be rated for 15 or at most 20 amperes. Note the rating so you can buy the same size if the fuse tests blown. To understand socket ratings and panel configurations, see our guide on circuit breakers vs fuses.
Method 1: Continuity Test
A continuity test on a fuse provides the fastest check because the meter gives an audible tone when the electrical path is complete. Plug the black lead into the COM jack and the red lead into the voltage and resistance jack, as shown in our guide on how to use a multimeter.
Turn the meter dial to the continuity position. Fluke notes this mode is often combined with the sound symbol on the dial. Test the meter first by touching the tips of the two probes together. If the meter is functioning properly, it should emit a clear beep. Continuity mode works the same way on switches and cords, as shown in checking continuity with a multimeter.
Place one probe firmly against one metal end terminal of the fuse, and place the other probe against the opposite terminal. Make stable, solid contact on both ends. If the meter beeps, the fuse has a complete internal path and is good. If the meter remains silent, the internal element is broken and the fuse is blown. As documented in the Fluke 15B/17B user manual, the continuity beeper sounds when circuit resistance is below 50 ohms (Ω). Other meters use different beep thresholds, so a beep only means the resistance is under that meter's limit.
Method 2: Resistance (Ohms) Test
A resistance test gives a numerical measurement of the fuse element. Turn the meter selection dial to the resistance setting, marked with the Greek letter omega (Ω). For a full breakdown of dial markings, check our reference on what each dial marking means.
Keep the fuse isolated and disconnected from any power source. Hold the red probe on one terminal and the black probe on the other terminal. Observe the digital display.
According to Fluke, an intact fuse displays a low resistance reading, usually 0 ohms or close to it. An open, blown fuse displays an infinite resistance reading. On digital multimeters, this often appears as over limit (OL) or a display of 1. Any reading showing infinite resistance confirms the fuse is bad.
Multimeter Fuse Readings
Whether testing in continuity or resistance mode, multimeter readings for fuses fall into two distinct categories.
| Meter mode | Good fuse | Blown fuse | Source |
|---|---|---|---|
| Continuity | Audible beep | No beep (silence) | Fluke fuse testing guide |
| Resistance (Ω) | 0 Ω or close to it | OL or "1" (infinite resistance) | Fluke fuse testing guide |
Visual Inspection Limits
You can sometimes tell if a fuse is blown simply by looking at it. Fluke notes that visual signs include a visibly broken wire inside the fuse or a darkened, burnt appearance on the body. This applies readily to clear glass tube fuses, clear-window plug fuses, and automotive blade fuses.
A visual inspection alone is not reliable. Opaque ceramic bodies hide the internal element, making visual confirmation impossible. A clean-looking glass or blade fuse is still not proof that the element is intact.
Testing with a multimeter eliminates this uncertainty. If a fuse looks clean and unburnt but yields no beep or shows OL on the meter display, the fuse is blown and must be discarded.
Replacing a Blown Fuse
A fuse opens once and must be replaced to reconnect the circuit, as noted in the CPSC Guide to Home Wiring Hazards. When replacing any fuse, use a fuse with the same amperage rating. Never install a fuse with a higher ampere rating than specified for the circuit.
The CPSC explains that consumers sometimes replace a repeatedly blowing fuse with a higher-rated one. A higher-rated fuse may not protect the branch wiring, and the CPSC warns the overloading that follows can lead to fire. The CPSC also warns that you must never insert any object other than an approved fuse into a fuse holder.
If a newly installed fuse blows right away, stop and call a licensed electrician. The CPSC advises tracking which circuits and appliances are active when a fuse blows. If a fuse blows when a particular switch, light or outlet is used, the CPSC says to get help from a qualified electrician.
Your Multimeter Has Fuses Too
Digital multimeters contain internal fuses to protect their sensitive measurement circuits. As Fluke explains in its guide to tester fuses, the current-measuring inputs route electricity through a very low-resistance shunt. A common accident occurs when someone measures current, leaves the test leads plugged into the amps jacks, and then tries to measure voltage across a live source.
This mistake places a direct short across the voltage source. High-energy meter fuses are designed to keep the energy of that short inside the fuse enclosure. Replacing them with unrated fuses or wrapping wires around blown fuses creates what Fluke describes as a thermal hand grenade.
The meter's fuses protect only the current-measuring inputs. For example, the Fluke 15B and 17B feature a 10 A input terminal and a separate terminal for milliamps (mA) and microamps (µA) up to 400 mA, both clearly marked FUSED. You can test these internal fuses without opening the meter case by following the procedure in the Fluke 15B/17B user manual.
Turn the dial to resistance mode, plug one test lead into the voltage/ohms jack, and touch the probe tip directly into the A jack or the mA/µA jack. On the Fluke 15B/17B, a good 10 A fuse reads between 000.0 Ω and 000.1 Ω, while a good mA/µA fuse reads between 0.990 kilohms (kΩ) and 1.010 kΩ. If the display reads OL, that fuse is blown. Remove the test leads before opening the case and fit the exact specified replacement fuse. These exact values are specific to the Fluke 15B/17B, so always consult your own meter manual for model-specific figures.
When to Call a Licensed Electrician
A homeowner can safely test a fuse once it is removed from a disconnected circuit or powered-off panel. Work inside the main service panel, however, requires distinct caution. If your fuse box displays scorch marks, contains damaged wiring, or uses main cartridge fuses you are unsure how to handle safely, contact a licensed electrician.
According to the CPSC, call a qualified electrician if fuses keep blowing. For persistent circuit overloads or obsolete service boxes, an upgrade may be warranted, as outlined in our breakdown of electrical panel replacement costs.
Never pull or insert fuses in an energized electrical panel. Turn off the main disconnect before servicing panel fuses, and call a licensed electrician if you observe arcing, burning, or repeated circuit failures.
Common questions
What should a fuse read in ohms?
According to Fluke, an intact fuse should read 0 ohms or close to it on a digital multimeter. A blown fuse will display an infinite resistance reading, shown as OL or 1 on the screen.
Will a multimeter still work with a blown fuse?
Multimeter fuses protect the current-measuring input jacks (A and mA/µA). If an internal meter fuse blows, current measurements on that input will not work, while other functions may still operate. Check your meter manual to test the meter fuses directly.
How can you tell if a fuse is blown?
With the power off, remove the fuse, set your multimeter to continuity mode, and touch a probe to each end. An audible beep means the fuse is good, while complete silence means the fuse is blown.
Can you do a continuity test on a fuse?
Yes, Fluke recommends continuity mode because it provides an immediate audible signal when an electrical path exists across the fuse terminals.
How can you tell if a fuse is bad by looking at it?
Visual inspection can reveal a broken internal element wire or darkened, burnt glass in transparent tube and blade fuses. Opaque ceramic fuses cannot be checked visually, so testing with a multimeter is always the reliable method.