Why My Microwave Blows Fuse When Started

We have some appliances that you must have in your house. One of these units is a handy microwave. Owning such an appliance not only proves that you are up-to-date, but also shows how you love your family. Like any other electronic appliance, microwaves are equipped with several fuses to serve a certain role. This means that when one of the fuses fails, the unit is likely to misbehave.

Blown fuse in microwaves can be as a result of high-voltage capacitor, poor installation, and external faults. Fuses play a critical role of sensing common problems to your microwave like power surges and unclosed doors. Fortunately, such problems can be fixed and that’s why we are here.

It is possible for microwave fuses to blow when you start your appliance. Let not these misfortunes scare you from owning a microwave because they make work easier as well as upgrading your kitchen. Everything has been packaged in this article for you; continue reading!

Quick table:


Reason/how it works


High-voltage capacitor

How to replace a capacitor in microwaves

Step 1: Shut down the microwave.

To detach your microwave from the source of power


Step 2: Unscrew the mounting screws.

Eliminate the cabinet screws

A Screwdriver

Step 3: Remove the access panel

To access the entire microwave unit

a screwdriver

Step 4: Detach the wire harness.

So that you remain with a plain microwave unit

A Needle-nose pliers

Step 5: Remove the bad hi-voltage capacitor

To replace the bad capacitor

Hi-volt microwave capacitor

Step 6: Test the capacitor

To examine the well-being of the high-volt capacitor to know whether you need a replacement or not

A digital multimeter

Reasons and solutions for blown fuses in a microwave when started

microwave blows fuse when started

I don’t know the exact problem with your microwave, but it may be one of the following. Under this section, we will enlighten you about the factors for blown fuses in microwaves when started. Let’s explore me:

1. High-voltage capacitor

High-voltage capacitors might be the suspected issue, posing challenges like a blown fuse in your microwave.

Capacitors are always essential for electrical storage before supplying it to the unit. Electricity is released faster for quick use.

Based on the name, the high-voltage capacitor abridges large amounts of electricity. Therefore if your appliance is operating with a problematic hi-voltage capacitor, the fuse is likely to blow when a microwave is powered on.

Opting for hi-voltage capacitor replacement can be the reason for its miseries. Sometimes the installation process of the new capacitor may be the root cause for blown fuses; maybe the technician “slept” on the job. Or maybe the capacitor was damaged during transportation.

On the other hand, an old capacitor can be the source of a blown fuse in your microwave. Aging is normal in any appliance and because of natural wear and tear; your appliance’s fuses may become flawed.

Furthermore, power surges pose a challenge to microwave’s fuses, and when you turn on your appliance, it is likely to blow.

How to replace a capacitor in microwaves

Substituting the capacitor remains the most reliable healing actions to unceasingly blowing fuses when you start your microwave. Since we have different microwave types, changing the capacitor may differ to some extents. For instance, you may be forced to remove various parts like access panels using a handy screwdriver.

Sometimes, you may also be forced to disconnect the control panel or grille. Follow these steps;

Step 1: Shut down the microwave

There is no big deal in this step because it involves detaching your microwave from the electricity source.

Step 2: Unscrew the mounting screws

This action is only significant if your microwave was initially installed in the cabinet.  Eliminate the screws and put the appliance on a safe surface for the repair process. A handy screwdriver should help you out. Check on amazon for the best screwdriver.

Step 3: Remove the access panel

Under this step, you’re required to disconnect the access panels to your microwave from the cabinet. Just ensure you take out your appliance from its location.

Step 4: Detach the wire harness

Before you arrive at this step, it is advisable to wait for something like 12 minutes before powering on your microwave.

Step 5: Remove the bad hi-voltage capacitor

Take your needle-nose pliers and remove the capacitor wires. You’re advised to confirm the safety warnings before you discharge the capacitor. Check on amazon for the best needle-nose pliers.

Unscrew the screws holding the capacitor mounting bracket before disconnecting the capacitor from your appliance.

Step 6: Test the capacitor

This step involves using a digital multimeter to examine the well-being of the high-volt capacitor to know whether you need a replacement or not.   

2. Power-outlet problems

Power-outlet problems

Sometimes, microwaves misbehave or blow their fuses when connected to another power socket. Yes, it’s possible due to the wirings of the power route being meant to support only lighter appliances such as TVs. You can try this solution and see if it works for you;

Easy fix:

Step 1

Plug your microwave to another available power source and observe the behavior. It may reveal to you the issues with your faulty electrical wiring, leading to blown fuses in the unit.

Step 2

For this case, it is advisable to call an expert to review and correct the electricity wiring in your house.

3. Poor installation

Poor installation

Many people overlook this mistake and end up regretting it in the future. The fuse blows continuously when it wasn’t properly installed. Alternatively, the blows might be due to the technician installing an incompatible fuse type; incompatible one.

This is now the reason why experienced electricians will advise you to opt for compatible fuse replacements whenever your device becomes defective.

Therefore, immediately when you power on the microwave, there are high chances for it to blow. This is hectic, especially when you are about to warm your after-work food. Well, you use the following easy fix to solve the issues;

Easy fix:

Step 1: Buy a quality fuse

To prevent such faults from occurring, I would urge you to invest in a high quality microwave fuse.

Step 2: Contact an experienced electrician

Secondly, seeking the advice of an experienced electrician is highly recommended so that you don’t end up buying the wrong fuse for a replacement.

Step 3: Properly install the fuse

Thirdly, ensure that the fuse is installed correctly; you may take your microwave to a trustworthy fellow.

Failure to do so will leave you with a lot of regrets, incurring unnecessary costs like buying replacement fuses. Opt for good quality and let it be installed properly to save future expenses.

4. Defective parts

Maybe your microwave is operating with a broken or faulty part. As a result of this, fuses will be blow whenever you place your finger on the ON button. The magnetron and the defective high-voltage capacitor are some of the root causes to be held responsible under this section.

Easy fix:

The best thing you can opt for is the replacement, but you should first make sure this is the exact problem. Start by testing these components before replacing them. In Particular, they are hazardous and therefore I’d advise you to call an expert.

5. External problems

Since you already know that power surge is the common culprit for blown fuses in microwaves, it is wise to work on it immediately. Power surges are known for either executing your electrical circuit breaker panel or blowing the main fuse.

Easy fix:

Handling this complication is very simple since it only involves substituting the fuse. However, you should start by checking your electrical panel. If the circuit breaker is tripped; this action may solve the issue.


  • Does my microwave require a special fuse?

Yes, these appliances come with various fuses, designed to perform specific functions. They are the ones to determine safe operation, for example a main fuse will cut the electricity flow if it’s too much. On the other hand, thermal fuses are responsible for preventing fuse blows during a too hot situation.

  • Can a 20 amp fuse work in my microwave?

Yes, but you’ve to make sure the ratings are compatible; they should match. However, the most preferably fuses are the Ceramic ones over glass fuses since they are associated with thermal protection and arc.

This is the exact reason why they’re fitted in high-current units such as microwave ovens.

Final words

Manufacturers are always trying to ensure that what they produce is safe and best for consumers. This applies similarly to microwaves; they feature safety mechanisms like fuses for safe and better operation.

In this article our aim has been to educate you on various factors that could lead to Microwave blows fuse when started. That wasn’t the end, we move ahead to provide you with a reliable guide on how to correct microwave blows fuse when started.

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