How to Test House Fuses with a Multimeter

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How to Test House Fuses with a Multimeter

Older homes and cars do not use modern circuit breakers but instead, make use of use fuses to avoid damage resulting from electrical flows. If your house circuit fails to work correctly, this means there is a problem with your house’s fuse. This thus means you need to run a test using a multimeter to test your house’s fuse to check whether it is working or not. 

Therefore, if you are looking to learn how to test a house fuse with a multimeter, you have come to the right place as in this article, you will be taken through a step by step process on how to do this. Without wasting much time, let us dive in on the procedures you need to follow when testing a house fuse with a multimeter. 

Understanding the fuses

The objective of fuses is to avoid damage to the more crucial electrical equipment and consequently resulting in a fire breakout caused by excess current flow. However, with a fuse in place, whenever there is surplus power flowing, it will automatically break down hence opening the circuit and stopping power from flowing through it.

Moreover, it would be best if you also took note that fuses come in a variety of numbers, which are distinguished primarily by their appearance. These categories include:

  • The blade fuse: This is the most popular fuse, and it has been in use for the past 20-30 years. They incorporate a vague resemblance of the power cord plug with two metal prongs proceeding from malleable housing that contains wires. Additionally, it can house numerous wires in a relatively small space.
  • The cartridge fuse: This fuse has, for many years, been used in numerous devices, that is, from electronic as well as home devices. They are usually made of terminal points on both ends with pipes that hold wires and are cylindrical.

Have basic knowledge on how a multimeter works

A multimeter is vital as it allows you to measure both D.C. and A.C. voltage, as well as the flow of power and electrical resistance. However, when testing a fuse, you can either use it as an ammeter that is responsible for checking the flow of electricity or ohmmeter for testing resistance. Typically, a multimeter has both negative and positive lead. Therefore, when you are analyzing resistance flow in the circuit, there will be a transmission of a minimal quantity of electricity from the battery then measure appropriately the amount that passes through the object.

Understanding why it is necessary to test fuses

Why must you run a test on your house fuses? Well, these tests are essential as they allow you to know whether the fuses in the electrical systems of your house are still functioning correctly. Whereas it is often difficult to test electrical tools, the same does not apply when it comes to the testing of fuses, as the process is usually very straightforward.

Some house components incorporate complicated wiring systems, thereby necessitating you to visit a repair shop, which is generally costly. However, this does not have to be the case when using a multimeter since it is not only cheap but also straightforward to use.

Most types of fuses usually show whether or not the fuse is still functional. This is because they have been made to display for your visualization to know if the wires are still functioning. Therefore, in case the wire turns black, this means that your fuse is damaged, and other fuses produce a black stain on them after overheating even slightly.

Typically such an incident can take you probably long to notice. Therefore, if the fuses are not appropriately, make sure you run a test on each of them, and if they are still working, there is a possibility that there is a serious problem that needs an expert.

Steps to follow when testing the fuse

Turn off the house’s power before you remove the fuse

Turn off electricity running in your house before you even decide to start testing whether or not the fuse is still working. Afterward, carefully remove your fuse by pulling it straight out of its position.

Turn on your multimeter and set it

Set your multimeter on OHMS for resistance measurement before you run your test on your fuse. Put the negative and the positive leads altogether and check out the readings; the figure shown needs to be close to that one displayed when you run the test on the fuse.

Put the lead on each end of the fuse and observe the display

During this process, put the lead on each end of the fuse and observe the screen, do not worry about which side will receive the negative or positive lead since fuses usually have more than just a distinct wire.

Test the fuse

In case you are using a multimeter for ohms’ measurement, you should have a reading that corresponds to the one displayed when you tested the two leads. If your fuse is blown, it will not have any reading or an open-loop(O.L.) that will be displayed on your multimeter depending on the type and brand of the multimeter that you are using.

In case you are running your test using a digital multimeter, you are supposed to set it for continuity measurement, and observe as it continuously beeps while holding the leads on the end of the fuse.

If it beeps continuously, it means that your circuit is complete and does not have a problem. However, if it fails to beep continuously, your fuse has probably blown and needs to be replaced immediately. Any time you want to run your test using a multimeter, always make sure you examine if your multimeter is working appropriately before going ahead to holding the two probes together.

Thus, when you hear a beep from your multimeter, it means it is functioning appropriately. Moreover, check whether your circuit is generating too much energy to display a reading on your multimeter if it is so you should lower the power source’s output using a resistor.

Conclusion

Having read through the article, you now know how to test a house fuse with a multimeter, which is often the best option when it comes to testing the house fuse. Therefore, with the above information, you should now feel confident enough to use your multimeter while still observing the extremely important safety measures. Consequently, you will be able to quickly tell whether or not your house fuse is damaged or not.

About the Author Dan

Just a random guy who likes to build things. Providing tool knowledge, appliance/device testing tips, and DIY project info in an easy-to read & non-intimidating style.