Microwave Sparkling: What it Means and How to Fix it

Do you happen to notice a tiny spark in your microwave today while baking the potatoes? If yes, then on the surface level you might not see a problem or you might have ignored it but that doesn’t mean there is no problem. There is some minor or major problem with your microwave unit that needs to be rectified ASAP.

What is a Microwave Spark?

Microwave spark is an emission of fire or electricity inside the microwave. This can be easily noticed while doing microwave-based cooking. 

However, this situation is not for you to panic but to go ahead and take the necessary steps. Sparking inside a microwave is very common and doesn’t always lead to damage to your microwave. Sometimes it can be just an alarming sight.

Basically, there are few reasons why your microwave might misbehave and can end up leaving a spark. They are –

Worn Rack Support

Some microwaves come in with a cooling rack. These cooking racks happen to have a smallholding placed in it. The supports are made up of metal and coated with plastic to provide extra protection.

The plastic material is not very high maintenance and thus can wear off easily. Once the plastic is worn off, metal is then exposed which makes your microwave spark while cooking your favorite food.

How to Fix it?

If anytime, you happen to notice this, run off to the market and get a new covering. Remove the old one and replace it with the new one. If you do not like to do it yourself, hiring a professional is always a good option.

Beware of the Piece of Metal

The tiniest piece of metal in your microwave can make it spark. A forgotten spoon, fork, or knife might not be there anymore but do not forget to look for the smallest piece of aluminum foil or such other thing.

Microwaves are absorbed by fat and sugar in the foods. When a piece of metal is left inside the appliance, it makes the electrons move around in the microwave. These produce sparks and heat that can damage your microwave. The damage can be either permanent or repairable.

How to Fix it?

As soon as you remove the metal from the microwave, sparking will stop instantly. Just switch off the microwave and inspect properly, remove all the metal pieces and your microwave will not give any more sparks.

Keep Waveguide Cover Clean

A waveguide cover is designed and is placed in to protect the electronics in the microwave oven. Look carefully in your microwave, you will notice a small mesh square halfway on one of either side. This plastic-covered metal is called Waveguide cover.

Waveguide’s job is to direct the waves towards the food that you are cooking. While in the process, the cover gets soiled with food splatter which provokes your microwave to spark.

How to Fix it?

In case if you happen to notice a spark, and find that the waveguide cover is at fault, make sure you clean the waveguide cover. You can either use a damp sponge or simply a paper towel.

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High-Voltage diode is at the Fault.

The last time you baked the cake, it only took 3 minutes but now it is taking forever. Do you also face such issues with your microwave? If yes, then the high-voltage diode is the one who is at fault.

High-voltage diode supplies power to magnetron to heat your favorite food and beverage in the microwave. If your microwave is consuming more time in cooking than before then its time to replace the high-voltage diode.

How to Fix it?

You can get a new diode from any local hardware shop and replace it easily by following the instructions given on the packaging. If you are not too comfortable doing it, take your microwave to any local appliance repair shop and they will do the needful for you in exchange of few bucks. Of course!

How to Test the Diode with Multimeter?

Not sure whether a diode is at the fault? Well, here is what you can do –

  1. Unplug your appliance from the power source and now it is time to handle electrical components.
  2. Remove the outer cabinet and make sure you discharge the capacitor to avoid electric shocks.
  3. Now carefully spot and remove the high-voltage diode to test it for continuity.
  4. You will be required to check for continuity in both directions. If the outcome shows continuity on both directions and there is absence of continuity in either direction, you will have to replace the high-voltage diode.

How to Test the Diode with Multimeter

Say No to Grapes

We know this may have come to you as a shock but its true. Cutting a grape in to nearly half and then microwaving it can cause a formation of plasma and balls of light in your microwave.

This can harm your microwave a lot and you might not be able to use the appliance in future. So, do not try it at home and keep your microwave away from the grapes.

How to Fix it?

The solution is very simple, switch off the microwave and remove the piece of grape.

Incompatible Cookware

You might have noticed that many companies advertise their products as microwave friendly. But still there is a high chance of getting confused about what to use and what to avoid. In this scenario, you may end up using incompatible cookware.

This might become the reason for the spark in your microwave. Therefore, it is very essential to use the right utensils while cooking in the microwave.

How to Fix it?

Do not make the same mistake twice. Switch off the appliance and remove the respective utensil. From next time make sure you are using the compatible ones.

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Faulty Stirrer

Job of the stirrer is to ensure that all food gets heated properly. It ensures the even distribution of energy in your microwave. If your microwave is not working properly or you notice that the energy is getting concentrated on one place then the same can lead to sparking and burning. This might happen due to the fault in the stirrer belt.

How to Fix it?

This fix gets a little tricky. First things first, you need to disconnect the power to your source in order to find out the actual fault. The next step requires you to remove the outer cabinet. Usually, you can find the stirrer belt on the upper side of the microwave.

Now you need to examine the belt so that you are sure that it is not blocking any movement. In case you notice any burning or such other damages, then you need to replace the stirrer belt.

Broken Drive Motor

This one is very easy to identify as all the latest models are designed with a default turntable. So, if the plate is not roaming that means there is a problem that requires to be fixed. Not turning of tables may or may not produce sparks.

How to Fix it?

Now this is something that gets a little too technical. So, the best option is to leave this job to the professionals.

Chipped Paint

Microwave is painted from the inside and there are chances of paint getting chipped. When the paint is chipped, the metal is exposed and causes a spark. Scrutinize the interiors properly for any such chipped-away spots.

How to Fix it?

Once you have successfully spotted the spots, touch them up with microwave paint. You can buy the paint or just dial-up for a professional.       

How Dangerous can a Sparking Microwave Be?

Microwaves are very kind to humans. Even if you notice a spark, you are not going to get hurt by it. All you have to do after you notice a spark is to go ahead and switch it off immediately. Sparks does have some cons; it may damage your appliance permanently.

Microwaves even while sparking are not dangerous to you, they only harm themselves.

However, there is one exception to this. If the sparking is caused by broken electronics, then there are chances of getting an electric shock. To avoid this situation, it is always better to just unplug the appliance. This way you will be safe and you can later investigate the problem closely.

Can I Use Microwave Post Spark?

Yes, you can. Most of the sparking issues are just because of carelessness and lack of knowledge about the appliance. It gets rectified easily. However, if the issue is bigger, make sure you consult a professional before using the microwave again.

Is Radiation Leakage a Problem?

Generally, due to old or loose doors, microwaves happen to leak radiation. However, radiation leakage does not result in sparking. But in case if you wish to avoid this, make sure you clean the microwave properly so that no crusty food gets choked up inside the door gasket.

How to Stop a Microwave from Sparking?

We have already discussed what is microwave sparking and how to fix it. But once you have figured out the original problem, it gets important to fix the problem. Listed below is the standard procedure that one should follow in order to stop a sparking microwave. They are –

  1. The first step is to unplug the microwave immediately. If the sparks are too bright or seemed to come from the walls of the microwave, unplug and turning it off is the smartest move.
  2. Check your microwave thoroughly. If you find cutlery or left a metal dish inside the microwave, you already know how to stop the sparking. Just remove the items that were causing the problems.
  3. In case if you do not find any metal wire, then go ahead and check the waveguide cover. If you notice a crack or damage, then that might have caused the spark. Just replace it and you are good to go.
  4. Nor the metal is the problem neither the waveguide cover, then the culprit is the faulty diode. In that case, just go and call a professional to solve the problem. There are chances that a professional might surprise you with another problem.

Materials that Attract the Spark

There are few materials that you would like to keep away from your microwave to keep your microwave safe. Given below are some of the materials that will definitely cause a spark.

  1. Metal Cutlery – Anything that a has a metal substance is the bad news for your microwave.
  2. Tin Foil – Tin foil is an aluminum foil that is used to wrap the food. This can become a cause for the accidental spark. Remember to unwrap your food before you decide to warm it up in a microwave.
  3. Pop tart Wrappers – Pop tart wrappers are like tin foil. They are used in wrapping breakfast and bakery items. Just like tin foil, remove the wrappers before you heat your food.
  4. Steel Wool – Steel wool is two steps ahead in the game. It is flammable in nature and can be more dangerous than metal and foil. It is highly inadvisable to use such fabric while cleaning your microwave.


If we overview the article, one thing gets very clear. In most cases, the spark is provoked by the metal. Either you have left the metal inside or depreciated parts have exposed the metals. No matter what has caused the problem, the solution is to stay composed and take the necessary steps.

We hope we were able to help you get out of the microwave sparking problem. If you have more issues, we are more than happy to help. Just nudge us with a comment and we will back with a quick fix for you.

Mila Patel

Mila Patel is an expert in consumer technology and household appliances who earned her degree in industrial design from Georgia Tech. She brings over a decade of experience from her time at Consumer Reports and as a freelance product reviewer. Her professional journey includes working with major appliance manufacturers and contributing to home improvement magazines. Her hobbies include interior design and staying updated with smart home trends. She also enjoys cooking and experimenting with the latest kitchen gadgets in her free time.

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