A fuse is working if your multimeter shows continuity or near-zero resistance

A multimeter is a handheld tool that measures electrical properties. When you touch its two probes to a fuse, it tells you whether electricity can flow through it. A working fuse shows continuity (a beep or a reading close to zero ohms). A blown fuse shows no continuity (silence, or a reading of infinity or OL, meaning "open line").

You do not need to remove the fuse from the circuit to test it, though removing it makes the test safer and clearer. The test takes about 30 seconds once you know which setting to use.

Key Takeaways

  • Set your multimeter to the continuity setting (often marked with a sound-wave symbol) or to the 200-ohm resistance setting.
  • Touch one probe to each end of the fuse; a beep or a reading near zero means the fuse is good.
  • A blown fuse shows no beep and a reading of infinity or OL; replace it with one rated for the same amperage.
  • Remove the fuse from its holder before testing if you are uncomfortable working with live circuits.

Locate the continuity or resistance setting on your multimeter

Most multimeters have a dial with multiple settings. Look for a symbol that looks like a sound wave or musical note — that is the continuity setting, and it usually beeps when electricity can flow. If your multimeter does not have a continuity setting, use the resistance setting instead, usually marked with the Greek letter omega (Ω). Start with the 200-ohm range if your dial has multiple resistance ranges.

Turn the dial to your chosen setting. If you are using resistance mode, the display should show a number — usually between 0 and 200 — when the probes are not touching anything.

Remove the fuse safely from its holder

Fuses sit in clips or cartridge holders, usually in a fuse box or panel. Turn off the main power switch to the circuit you are testing if you can identify it. If you cannot, or if you are testing a fuse in a car, you can test it while it is still in the holder, though removing it is safer.

Grasp the fuse by its body (not the metal ends) and pull it straight out. Some fuses have a small handle or tab to grip. Set it on a clean, dry surface. Do not touch the metal ends with your bare fingers while testing, as oils from your skin can affect the reading.

Touch the multimeter probes to each end of the fuse

Hold the fuse steady with one hand. With your other hand, touch the red probe to one metal end of the fuse and the black probe to the other metal end. Press firmly so the probe tips make clear contact with the metal.

If you are using continuity mode, listen for a beep. If you are using resistance mode, look at the display. A working fuse shows a reading between 0 and 10 ohms, or a beep in continuity mode. A blown fuse shows no beep and a reading of infinity, OL, or 1 on the display.

Understand what the reading means

A continuity beep or a resistance reading close to zero means the fuse is intact and electricity can flow through it. The fuse is good and can go back in its holder.

No beep and a reading of infinity, OL, or 1 means the fuse is blown. The metal filament inside has broken, and no electricity can flow. You need to replace it with a new fuse rated for the same amperage. The amperage is printed on the fuse body — common ratings are 5A, 10A, 15A, 20A, and 30A. Using a fuse with the wrong amperage can damage equipment or create a fire hazard.

Replace a blown fuse with the correct rating

Before you insert a new fuse, find out why the old one blew. A single blown fuse can happen by chance, but repeated blown fuses usually mean a short circuit or an overloaded circuit. If you replace the fuse and it blows again within days or weeks, the circuit has a problem that needs professional repair.

Insert the new fuse into the holder with the same orientation as the old one — the metal ends should face the clips. Push it in until it clicks or seats fully. Turn the main power back on if you turned it off. Test the circuit to confirm it works.

Test a fuse while it is still in the holder

If you do not want to remove the fuse, you can test it in place. Set your multimeter to continuity or resistance mode as before. Locate the two metal ends of the fuse where it sits in the holder — they may be slightly recessed or hard to reach. Touch one probe to each metal end and read the result the same way you would for a removed fuse.

Testing in place is less reliable because dirt, corrosion, or a loose clip can give you a false reading. If you get an unclear result, remove the fuse and test it on a clean surface.

Frequently Asked Questions

Can I test a fuse without removing it?

Yes, you can touch the probes to the metal ends while the fuse is in the holder, but the result may be less clear if the clips are dirty or loose. Removing the fuse gives you a more reliable reading and is safer if you are not sure whether the circuit is live.

What does OL mean on my multimeter display?

OL stands for "open line" and means there is no continuity — no electricity can flow. A fuse showing OL is blown and needs to be replaced.

Can I use any fuse as a replacement?

No. Always replace a fuse with one rated for the same amperage, printed on the fuse body. Using a higher-rated fuse can let too much current flow and damage equipment or start a fire. Using a lower-rated fuse will blow immediately.

Why does my fuse keep blowing?

A single blown fuse is usually random, but repeated failures mean the circuit is drawing too much power or has a short circuit. Stop replacing the fuse and have the circuit inspected by an electrician or technician, depending on whether it is in your home or a device.

Do I need to turn off power before testing a fuse?

Turning off power is the safest approach, especially if you are new to using a multimeter. If you cannot turn off the circuit, you can still test the fuse in place, but avoid touching the metal clips or any other part of the circuit.