It can be challenging to test a fuse if you don’t know how to do it. With so many electric and electronic items that need to be checked, it is crucial to understand how to use a multimeter. There will be no need to call an electrician for simple tasks such as a blown fuse. The article will show you the steps involved to test a fuse with a multimeter despite the fuse type.
When testing a fuse using a multimeter, you should check these things to detect a good fuse and blown one:
- Measure resistance if a fuse is blown
- Consider the voltage of a fuse
- Check the current state of the circuits
- Check the fuses in the fuse box
- Measure the number of ohms
Why is it Necessary to Test Fuses?
- The test will allow you to know whether the fuses in your house are functioning correctly.
- Since some house appliances have complicated wiring systems, electricians can be costly to do the testing for you. But with a multimeter, it is affordable and easy to use.
- You can use a multimeter to check if the fuse has an issue rather than replacing it without knowing if it is blown.
- The process of testing a fuse saves both money and time.
Different types of Fuses
A fuse is a device that serves as a failsafe if an electric circuit overloads. Fuses are in almost all the home appliances and the breaker box. They protect machines and users from fire, overheating, and overloading, leading to severe and permanent damage.
They are divided by the current they are used with, i.e., AC and DC fuse. Some are used one time only, while others are reusable. They include:
- Automotive fuses
These fuses are found underneath the driving wheel, near the stereo and window raising system of a vehicle. They are also known as High Rupturing Capacity Fuses (HRC). They can withstand high current at a time. If the current is not removed in time, the fuse blows out and protects the car from damage. The fuses are designed from metal, glass, and ceramics.
HRC fuse handles up to 32 voltage of direct current. You can easily spot the fuse because of its bright color. Because of their low reaction time and affordability, the fuses are excellent choices for many car manufacturers.
- Cartridge fuses
The fuse is made of glass or ceramics and is cylindrical. It withstands a specific amount of current before breaking down. It is fixed between two caps on each side, and it is space inside. When it overheats, the wire inside it melts, disconnecting currency from flowing to the other side hence breaking the circuit.
It is categorized into 2 types; time delay and general-purpose fuse. They are mostly found in stereos, TV, kitchen appliances, and a multimeter, among other devices.
- Power fuses
These types of fuses are found inside the fuse boxes and handle very high currencies. The power fuses are made of durable material and come in various shapes and sizes. It tends in case thunder hits an electric pole in around home and currency reaches your house. It will protect you and your house from the currency.
How a Multimeter Works
A multimeter is a device that measures both DC and AC voltage and also power flow and electrical resistance. When testing a fuse, you can use an ohmmeter responsible for testing resistance and an ammeter to check the electricity flow.
However, a multimeter is a combination of ammeter and ohmmeter; hence can analyze resistance flow in the circuit and an appropriate amount of electricity to pass through the component.
Units used in the multimeter
Voltage: is the force provided by an energy source that allows current to flow. It is used interchangeably with “potential difference,” but they are different.
Amperage: is the electric current, and it is measured in amps or amperes and is mainly used by electricians.
What causes a Fuse to Blow:
As stated above, a fuse protects the circuit from a higher current than a circuit can handle. There are various causes that can lead a fuse to blow. They include
- If the device draws higher current than its required amount
- When a metal object falls or plugged into a power socket
- The wire harshness that goes into appliances bends, shorts, or pops the fuse related to brake lights and taillights
- A wiring harness connected to some component inside the engine rubs through and shorts the fuse.
- If you install the wrong bulb in one of the taillights, the headlight can also pop the fuse.
- A damaged or rubbed trailer harness shorts the fuse.
Steps to Follow when Testing a Fuse:
Step 1: Turn off the power before removing the fuse
The first thing is to turn off running electricity in the house before testing if a fuse is in good or imperfect condition. Now remove the fuse carefully by pulling it straight.
Step 2: Turn on the multimeter and set it.
Turn the multimeter on and set it on OHMS for resistance measurement before testing the fuse. Make sure you check out the negative and positive leads and check out the readings—the figure shown needs to be close to the one displayed after testing the fuse.
Step 3: place the lead on each fuse end and check the display
Next, place the lead on the fuse ends and look at the screen. You can place any lead either on the positive or negative side because the fuse has more than a distinct wire.
Step 4: test the fuse
If you are running the multimeter for ohm’s measurement, the reading should correspond to the one displayed when you tested the leads. It will not show any reading on the multimeter for a fuse blown, depending on the multimeter type and brand.
When testing a fuse using a digital multimeter, you should set it for continuity measurement and check as it continuously beeps while holding the leads on the fuse ends. The fuse will not have an issue if it beeps continuously since the circuit is complete. But if it doesn’t beep continuously, your fuse has blown and needs to be replaced.
Before using a multimeter to test the fuse, ensure it is working properly before holding the two leads together. It is also essential to check the number of circuits being generated. In case the energy is too much, as displayed on the multimeter, you should use a resistor to lower the power output.
Frequently Asked Questions (FAQs)
Can you test a fuse without removing it?
Of course, yes to test a fuse without removing it through continuity or voltage or checks.
Can a fuse test good but be bad?
It can be possible but under certain uncommon situations.
Knowing how to use a multimeter test a fuse, you be safer in your home. You will be able to test if the circuits are in good condition. From now henceforth, you need to be confident to use a multimeter while testing to tell whether or not your fuse is damaged or not.
Purchase a digital multimeter and enjoy testing the fuse with ease.