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Microwave Trips Breaker When Door Opens – Here’s the Reason!

Written by Edwin Jones / Fact checked by Andrew Wright

microwave trips breaker when door opens

Do you lose power when you try to use your microwave? Do you want to know why the microwave trips breaker when door opens?

If your microwave keeps tripping breaker, there might be a problem with your circuit or the microwave itself. When you have a microwave tripping breaker when its door is open, you may have an issue with the door interlock switch. However, if the microwave trips breaker on startup, there might be some internal electrical problems.

Continue reading this article to get an idea of how to troubleshoot your circuit and your device.

Circuit Breaker Trip When the Microwave Door Opens

Door interlock switch location

If your circuit breaker gets tripped when you open your microwave door, it is likely related to the door interlock switch. A damaged door interlock switch may develop a fault when it activates. This fault is then detected by the circuit, which causes the breaker to trip immediately.

The door interlock switch is connected to latches or hooks. So it’s good to check them first before considering replacing the interlock switch. This interlock switch and latches are placed in the inner side of the cabinet where your monitor and timer are.

How to check?

Using a multimeter.


  • The door switch has cords that are connected to terminals. Connect the two probes of the multimeter to each terminal.
  • Check it for continuity with both the door opened and closed.
      • There should be no continuity if the door is open.
      • And if the door is closed, you should get a continuity reading.
      • If you get the opposite result from any of those, then the interlock switch is damaged.
  • Make sure your microwave is unplugged to avoid accidents.
  • DO NOT touch the capacitor as it may be fully charged even if you have unplugged the microwave.

Hearing the clicking sound.

Another way of checking for a damaged interlock switch is by listening for the clicking sound it makes. Meaning, if the switch has a good click sound, it may not be damaged, but if you hear a very tiny click sound or not having a click sound, you can consider the item is damaged.

However, this method could be inaccurate. You should only use this if you don’t have a multimeter. Checking the resistance reading is still the best way to diagnose your appliance.

Microwave Trips the Circuit Breaker on Startup


There are many possible causes why your microwave trips the circuit breaker on startup. Here are some of the most common reasons.

1. Circuit Overload

Sometimes you don’t notice that the circuit is overloading, especially if you don’t know which outlets are connected to which breaker. You should know if your outlet’s breaker has enough capacity to support all the appliances plugged into it. One of the best ways to do it is to have a particular circuit for each high-power device.

2. Faulty Turntable Motor


When cooking or heating foods in the microwave, sometimes some liquid flows under the turntable. This may then seep into the turntable motor, which could cause it to get damaged. To prevent this kind of problem, always clean the microwave and avoid spilling any liquid inside.

3. Broken Door Latch


A microwave has a door latch mechanism connected to the switches. The fuse may blow, or your breaker might trip when using your microwave with a broken latch. The best way of checking damaged latches is by using a multimeter.

4. Faulty Capacitor


A capacitor is one of the most important things microwaves have. If your microwave has a problematic capacitor, it may produce a loud noise when being used. It could also cause its fuse to blow and trip your breaker.

Before checking the capacitor, it is good to disconnect the power and short-circuit the capacitor using an insulated device.

5. Faulty Transformer


A transformer amplifies the electric current for the microwave’s magnetron. If the transformer is defective, this will cause a loud noise while you’re using it. It will also result in blowing a fuse or tripping the circuit breaker.

6. Faulty Timer


If your microwave’s timer gets jammed or damaged, it will immediately blow a fuse or trip a circuit breaker.

When any of these problems occur with your microwave, you should consult a certified electrician first. This is especially true if you’re not comfortable working with electronic devices or are unsure of what needs to get done.

If maintenance is done improperly, this could result in making your microwave inoperable altogether. And more than that, an improper repair could result in property damage or physical injury.

Is It the Circuit Breaker or the Microwave? How to Identify the Problem


The first thing you should do is to find the problem’s source. Is it with your microwave? Or with your circuit? To find out, try plugging in other appliances with the same power draw as the microwave into the particular circuit.

  • If it still trips even if you’re using a different device, then there’s a high possibility that the circuit has an issue. The tripping might be caused by an overload—which means that the breaker doesn’t have enough capacity to provide the required amperes. Read now this guide to calculate the most proper breaker amps for your microwave.
  • Now, if the breaker doesn’t trip at all with the previous test, you should check your microwave.

To do that, you need to plug the microwave into a different circuit with the same power rating. If the breaker trips, then the microwave might be the problem.

Generally, two common microwave problems cause tripped breakers. These are either a damaged fuse or faulty switches.


  • The first and easy way of troubleshooting a microwave is to check its fuse. If it’s burnt, has broken glass, or broken wire, then it needs to be replaced. If not, you should check the switches next.
  • Typically, a microwave contains three switches—one for the door, one for monitoring its systems, and one as the primary switch. Any of these could also be responsible for tripping your circuit breakers.


Knowing basic troubleshooting techniques for microwaves and circuit breakers will help save money and time. Some of these problems, like circuit overloading, also apply to any device.

Does this article give you a better explanation of why microwave trips breaker when door opens? If you have more follow-up questions, drop them in the comments section below! It would be a pleasure to help you.

Related guide: Detailed Steps to Reset a Tripped Circuit Breaker.

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