Why Are There Sparks in my Microwave?

If you witness sparks appearing in a microwave it can be a rather alarming sight.

However, the first thing to do in this situation, is not panic. This problem is usually relatively easy to fix if you can find the cause.

Sparks in the microwave are usually caused by the microwaves hitting a metal object inside the appliance. Metals conduct electricity with lots of electrons which move freely.

Microwaves are absorbed by fat and sugar in foods. If metal is put into the appliance, the microwaves cause the electrons to move around, producing sparks and heat.

Sparks occur simply due to a build-up of charged particles which produce a concentrated electric field at the edge of the metal object.

Read on to find the most common causes of sparks in a microwave and what to do in this situation.

Metal in the microwave

The mistake of putting a cup of coffee with a spoon into the microwaves. Metallic objects cannot be put into these devices.

It is important that in all cases when sparks are sighted inside your appliance, that the device is stopped, and the power is turned off. This will prevent further damage and help to prevent a fire breaking out.

In most cases where sparks appear in the appliance, it is likely because you have accidentally left a piece of metal in the microwave.

When the appliance is working, this will cause sparks to fly, and the metal should be taken out as soon as possible. If removed quickly enough this can usually prevent damage such as holes being burnt into the walls.

However, it is a good idea to get your appliance checked by a professional microwave repair technician before using it again.

Other metals that can cause issues in your microwave are foil or crockery items with metal trim – both of which should be avoided.

Broken microwave waveguide cover
In rare cases, if the microwave oven receives a lot of use, or is bashed or knocked, the waveguide cover – which allows energy waves to cook through your food –  in the device may become loose.

In addition, if food explodes inside the machine, something can become trapped under this cover and get into the inner workings of the microwave.

If this happens, then sparks can occur, and this should be looked at by a repair professional who can get the device running again, while keeping your home safe.

Faulty diode

Girl cleaning oven in the kitchen

A microwave diode is an essential part of your device and is used for generating, mixing, detecting and switching your microwave signals.

As they are heavily used, they can occasionally be worn down or split in two. This can then cause sparks, and if the diode has shorted, it will be accompanied by symptoms such as a loud humming.

If the diode is faulty but not shorted, no heat will be produced and there won’t be a humming noise. There can also be visual signs and a burning smell if a microwave has a faulty diode.

If either of these issues occur with your appliance, then it means that a microwave diode will need to be replaced by a professional

For more information on how to keep your machine running correctly, you may want to refer to our article on how microwaves work.

If you need further assistance with your appliance, don’t hesitate to get in touch with us as we are always delighted to help!