Why is There A Metal Rack in the Microwave? 7 Tips For Use

What is the metal rack in my microwave for

It’s mind-blowing. We’ve been told NEVER to put a metal object in the microwave. But then, we look in a new microwave and it has a big ol’ metal rack right there in the middle! How can this be?

And what is the metal rack in my microwave for?

The metal rack that comes inside of new microwaves can be safely used for cooking multiple items at once (e.g. one on the rack, and one on the spinning tray). The metal grilling rack is also useful for more evenly cooking and defrosting because it heats the food from all angles.

But, doesn’t this metal rack cause sparking (like other metal objects in the microwave)? And how can you make sure that you are using the rack safely? We’ll cover these questions and a few others next:

What is the Metal Rack in the Microwave for?

The metal cooking rack in the microwave has a couple of different purposes and benefits.

  • Heat multiple items at once
  • Prevents hot spots and cold spots
  • More even cooking and defrosting
  • Decrease cooking time

The metal rack that comes inside of new microwaves can be safely used for cooking multiple items at once (e.g. one on the rack, and one on the spinning tray).

The metal grilling rack is also useful for more evenly cooking and defrosting because it heats the food from all angles.

When normally heating food, you can get cold spots in the middle of your food. By cooking the food on the metal cooking rack, you prevent these temperature differences because microwaves can heat the food from the bottom as well as the sides.

Now that we know what the metal rack is used for, let’s talk about some tips to use it best.

7 Tips for Safely Using the Metal Microwave Rack

There are a few important considerations for properly using the metal rack in your microwave. Here’s a video from Samsung (one of the biggest appliance manufacturers) which provides an overview of how to use the metal rack in their microwave ovens:

This video touched on a few of the most important points for safely using the metal grilling rack. We’ll cover these, and a few more next.

1. Make Sure the Rack Is Installed Properly

To avoid sparking and other issues, the metal shelf must be installed using the plastic hooks on the inside of the microwave.

The metal rack should not come into contact with the microwave’s sides (or back). If the rack gets placed incorrectly and does come into contact with the microwave’s metal sides, then this can create sparks.

But, don’t worry too much about this, because the rack was designed to slide right into place on these plastic hooks, so it’s pretty easy to get right.

What is the metal rack in my microwave for

2. Remove the Metal Rack When Not in Use

The microwave comes with a metal rack inside, but according to Frigidaire, you should avoid storing the metal rack in your microwave.

In other words, if you’re not actively using the metal rack, then you should go ahead and remove it from the microwave and store it on a shelf, in a cabinet, etc.

What is the metal rack in my microwave for

3. Remember to Rotate Food

The metal rack is fixed, unlike the spinning tray at the bottom of a microwave. As a result, if you are cooking or reheating a meal inside your microwave, you might need to rotate or turn the food partway through cooking.

If you miss this step, then your food may not cook fully or evenly.

If you are cooking a pre-packaged meal, like a TV dinner or Hot Pocket, the packaging will likely include instructions. Check the instructions to see if there is a specific time that they recommend turning the food.

4. Do Not Use a Browning Dish

According to GE Appliances, you should avoid using a browning dish on your microwave’s metal rack, because doing so could damage the rack.

As you’ve seen from the earlier points, the microwave racks are fairly specific in their design, and if the rack is damaged or warped that could cause other problems.

5. Avoid Popping Popcorn

It is also recommended that you avoid popping popcorn when the metal rack is installed.

One potential issue with popping popcorn is that when the popcorn bag expands, it could push the metal rack off of its hooks. This could then cause several issues, including potentially sparking.

6. Do Not Run the Microwave Without Food

When your microwave contains a metal rack, you should also avoid running the microwave if it’s empty (e.g. no food inside).

It’s probably good practice to avoid ever running the microwave when it’s empty, but this is especially true when your microwave contains a metal grilling rack.

7. Use Microwave Safe Dishes

The video from Samsung also mentioned the importance of using microwave-safe dishes. Just because you’re using the grilling rack, doesn’t make you exempt from other normal microwave safety precautions.

So, use microwave-safe ceramic, microwave-safe plastic, etc. And you should be all set.

Why Does Metal Spark in the Microwave?

Let’s talk about what causes metal to spark in the microwave.

Metal sparks in the microwave when it builds up an electrical charge. Food is made up of mostly water molecules which absorb energy slower than metal. So, metal will build up a charge faster than food.

Then, this charge is released when the electrical charge is discharged into other metal such as the sides of the oven or another piece of metal.

Sharp edges or multiple edges build up more energy than flat surfaces. This creates an interesting phenomenon that means a flat circle of aluminum foil may not cause a spark but a crumpled piece of aluminium foil with lots of edges will spark a lot.

Now that we know why metal sparks in a microwave, let’s spend a little time on why the metal rack might spark in the microwave.

Metal Rack Causing Sparks in the Microwave

why is there a metal rack in the microwave

If your microwave rack begins sparking, then it’s very likely that there is an issue with how it is mounted.

First, if you see sparking inside of your microwave, then you should stop the microwave immediately.

Then, check to see if the rack is improperly installed and if it is coming into contact with the walls of the microwave at any point.

Also, keep in mind that microwaves are usually designed to work with the specific rack that comes with the unit. So, using a different metal rack may cause additional issues. Avoid using a metal rack other than the original one that came with the microwave.

If you are using the original rack, it appears to be installed correctly, and for some reason, your microwave is still sparking, then there may be a mechanical issue. Reach out to the support line of your appliance manufacturer for more information.

How Can a Microwave Have a Metal Rack?

Alright, now for the curious minds, let’s talk about how a microwave can have a metal rack in the first place.

The metal rack that comes with a modern microwave is specifically designed to avoid the conditions required to create sparks.

Sparking in a microwave is usually caused when metal comes into contact with the microwave’s internal metal surfaces (back, sides, etc.), or when there is metal inside that has sharp points or edges. For example, forks, aluminum foil, or twist-ties, can all cause sparking in a microwave.

Microwave racks avoid contact with the microwave’s metal walls because it is elevated and held in place with plastic clips or rubber clips. Microwave racks are also designed to avoid the types of edges that encourage sparking.

There is a lot of science that goes into all of this, but that is the simplified explanation. If you’d like a deeper understanding, below is a great video from the Huffington Post, which illustrates how the microwaves emitted by a microwave oven, can create sparks with certain shapes of metal.

Before watching this video, add the classic “don’t try this at home” disclaimer. This is interesting for informational purposes, but please avoid putting any metal (other than the original microwave rack) inside your microwave oven.

Can I Leave the Metal Rack in My Microwave?

You should remove the metal rack from your microwave unless you are actively using the rack. You should not store the rack inside your microwave. And if you are only using the bottom spinning tray in your microwave, then you should also remove the metal rack because it can prolong cooking times.

Can I Put a Plate in the Oven?

Plates can go in the oven if they are labeled as oven-safe. This label is usually found on the bottom of the plate. Common plate materials that are oven-safe are glass, ceramic, metal, and cast iron. If you put a plate that is not oven-safe in the oven, it could crack or break.

What Happens if You See Sparks in Your Microwave?

Firstly, stop your microwave immediately. Typically it means metal has accidentally been placed inside the microwave like a knife or fork, or perhaps a mug with a metallic finish. Remove the item and try again. If it keeps sparking, replace everything in the microwave with a basic ceramic mug, and fill it halfway with water. Try it again. If it sparks again stop using your microwave. Unfortunately, you will need to have your microwave repaired or replaced, the heating element in the microwave may be damaged.


Leslie has lived in tons of different places that were all in different states of repair. She has experience remodeling and replacing just about everything in a home including the roof. When she's not working on a project, Leslie blogs about home improvement tips to pass on her knowledge to others.

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