Microwave Sparking or Arcing Inside
Likely causes
- ✓Metal or foil left inside the microwave
- ✓Worn or damaged waveguide cover
- ✓Food debris burning on the guide cover or interior wall
- ✓Damaged interior paint exposing metal underneath
- ✓Failing magnetron
The short answer: stop using it right away. The most common cause is metal inside, or a burned waveguide cover on the inner wall.
That part is cheap, but it must be replaced before the unit runs again.
What usually causes it
- Metal inside. Foil, metal trim or twist-ties.
- Damaged waveguide cover. Burned splatter causes arcing.
- Food debris on the wall. Burns and sparks.
- Chipped interior paint. Exposes bare metal.
- Failing magnetron. Can cause arcing even when empty.
What you can check yourself
- Stop and unplug it. Sparking can damage the unit and start a fire.
- Check for metal. Look for foil, metal racks, metallic dish trim or twist-ties.
- Look inside. Check the small panel on the right wall for burn marks and the walls for chipped paint.
- Wipe off food residue with the unit unplugged, since burned splatter can arc.
How to prevent it
- Clean spills right away.
- Use only microwave-safe dishes.
- Cover food to reduce splatter.
When to call a technician
Call us if:
- It still sparks when empty and clean
- The waveguide cover looks burned or pitted
- There is smoke or a burning smell
These repairs involve live voltage, gas or hidden parts, so we recommend leaving them to a professional.
Service call: $89, waived when you go ahead with the repair. Warranty: 90 days on every repair.
Frequently asked questions
Why is my microwave sparking?
Metal, burned food or a damaged waveguide cover are the most common causes.
Is it safe to use after sparking?
We recommend not using it until it has been checked.
Can a waveguide cover be replaced?
Yes. It's an inexpensive part, but the unit shouldn't run until it's fixed.
This is one of the issues covered under our Microwave Repair service.