The ability to test fuses is crucial, as they are an integral part of almost every electronic system.
The ohmmeter feature on a multimeter can be used to test a fuse for spikes or surges. It is also a good idea to test its resistance to see if it allows proper current flow.
Fuses are a vital component of your home’s electrical system. When functioning properly, they can save lives, but a malfunction could have dire consequences.
The process of testing a fuse with a multimeter is not particularly difficult, and you may find that it is necessary to perform before installing new fuses.
As a first step, check that you are in possession of a suitable meter for testing fuses. You’ll need one that can switch between AC and DC power, and whose voltage can be adjusted to between 200 and 600 volts, or even higher, in order to test the fuses you intend to use.
Contents
The Importance of Fuse Testing
It’s never a pleasant surprise when a fuse blows. Fortunately, most of us know how to swap out a blown bulb and get going again as soon as possible.
However, some fuses can be quite costly, so if you don’t have any spares on hand, you might have to make an unwelcome trip to the auto parts store or the hardware store.
As someone with years of experience in this field, I can attest to the frequency with which such incidents occur, so it’s not just smart to carry around a few spare fuses in case one blows, but it’s also essential, especially given the low cost of fuses in comparison to other repair services like auto maintenance.
If you discover that your lights have gone out, you should always check the fuse before frantically searching for replacements. There are financial and time benefits to testing a fuse as well.
The cheapest way to see if an electrical problem, like a blown circuit breaker, has affected the electricity in your home is to turn on a single light bulb in the suspected area.
When an electrical overload occurs, it is able to break the fuse in half. When this occurs, we typically know whether or not there is electricity still flowing through the device by listening to its sound.
When you’re testing one last thing up against the wall socket as soon as possible after turning off any nearby circuit breakers, you might not know if your home has been disconnected from all power sources yet because fuses have tiny windows with small wires and it’s often hard to see inside their casings without really looking closely for long periods of time.
What Causes a Fuse to Blow?
A fuse prevents damage to an electrical circuit from current that is too high for the circuit’s capacity. A blown fuse usually indicates an issue with power and ground, or between two wires (car body).
A jammed wiper motor, for example, will cause the fuses to pop because it is using too much electricity, which is why they are there to begin with.
If a winding inside the motor is shorted, the same thing can happen. Common causes of blown fuses that we observed include the following:
- The most common cause of problems with your car’s taillights or brake lights is a short in your car’s wiring, which can occur when something (like a coin) falls onto or is plugged into the front accessory power socket.
- When you turn off a light switch near these sockets in the back of the trunk lid or liftgate on both sides, the wire harness will break at the bend, breaking contact between the circuits and causing the corresponding fuses to blow instantly. This is ideal for road trips.
- The fuse can also blow if you install the wrong bulb in your vehicle’s headlights or taillights.
- Let’s say your older Mercedes-engine Benz’s bay wiring harness is damaged, causing a wire to lose its insulation and short out to other wires. This issue will also arise as a result. If you’re cruising around at night and you notice sparks coming from under the hood every time you brake, something may have caused a fuse to short out and blow, so you should check the fuse again.
Testing a Fuse with a Multimeter
It is possible to measure voltage, current, and resistance with an electronic tool called a multimeter. It’s similar to a continuity tester, but with far more capabilities!
Some meters feature digital settings for measuring all three variables with varying degrees of precision, while others use analog dials and needles.
Whatever model you’re working with, it’s likely that you’ll have to measure resistances or before proceeding to any other measurements.
Typically, this dial is set to a range of roughly 200, but it can go as high as 2K (K stands for thousand, therefore 2K = 2000).
If the readings are less than 1 ohm, the fuse is OK; if the readings are infinite instead of a low reading, the fuse is blown and you should try again by jiggling the probes on both contacts to make adequate contact.
Check the Ohms With a Multimeter
If you want to test the ohms, you’ll need a multimeter with a resistance reading. You can tell if the fuse is blown or not by measuring the ohms.
Turn the Multimeter up to 20k.
You can gauge electrical resistance with the multimeter by using the ohms setting. Turn your device’s setting to 20k and examine the dials to see where they are centered.
Connect the Test Plugs
Verify the ohmmeter’s reading by making sure the testing probes are connected.
Probes Testing
When the resistance reading on a multimeter is close to 0, there is almost little resistance. If you press the points together and receive a reading of 1 or 100%, that shows your leads are solid.
Look for a Non-Metal Place
It is recommended that you first locate a surface that is not made of metal.
Remove the Fuse
Taking off the fuse will prevent the multimeter from blowing up during testing.
Fuse Inspect
Even if the fuse seems to be in good shape on the exterior, a broken wire on the inside could be the cause of the problem. You’ll need a new wire if you find any damage in that one.
Use the Test Leads to Make Sure the Fuse Is Working
The multimeter can be used to determine whether or not a fuse has been blown. The resistance between the probes should be near to zero ohms when placed on either end of the fuse, unless the car is more than 30 years old.
If you’re not confident about the accuracy of your measurement, touch the ends of the wires together with your probes; if they’re at ground potential (0V), you’ll find that the resistance between the points you contacted is exactly zero all the way back to the terminals.
Conclusion
The fuses in your home’s electrical system are an essential safety feature. They save lives when they work as intended, but if something goes wrong, it could be disastrous. Turning on a single light bulb is the cheapest way to test the electricity in your home after suspecting an electrical problem. A blown fuse indicates an electrical problem between two wires or with the power and ground (car body). The fuses will blow, as an example, if the wiper motor becomes jammed and draws too much current.
Changing the wrong bulb in your car’s headlights or taillights can also cause the fuse to explode. The ohms setting on a multimeter is used to measure electrical resistance. To find the device’s center, set it to 20k and look at the dials. It’s safe to assume your leads are good if pressing the points together gives you a reading of 1, or 100%.
Content Summary
- The ohmmeter feature on a multimeter can be used to test a fuse for spikes or surges.
- Fuses are a vital component of your home’s electrical system.
- You may need to test fuses with a multimeter before installing new ones.
- As a first step, check that you are in possession of a suitable meter for testing fuses.
- It’s never a pleasant surprise when a fuse blows.
- There are financial and time benefits to testing a fuse as well.
- A fuse prevents damage to an electrical circuit from a current that is too high for the circuit’s capacity.
- A blown fuse usually indicates an issue with power and ground or between two wires.
- Common reasons for blown fuses: When something (such a coin) falls on or is plugged into the front auxiliary power socket, it might cause a short in your car’s wiring.
- The fuse can also blow if you install the wrong bulb in your vehicle’s headlights or taillights.
- If you’re cruising around at night and you notice sparks coming from under the hood every time you brake, something may have caused a fuse to short out and blow, so you should check the fuse again.
- It is possible to measure voltage, current, and resistance with an electronic tool called a multimeter.
- If you want to test the ohms, you’ll need a multimeter with a resistance reading.
- You can tell if the fuse is blown or not by measuring the ohms.
- You can gauge electrical resistance with the multimeter by using the ohms setting.
- When the resistance reading on a multimeter is close to 0, there is almost little resistance.
- Taking off the fuse will prevent the multimeter from blowing up during testing.
- The multimeter can be used to determine whether or not a fuse has been blown.
