Microwave trips the house circuit breaker or blows a fuse when starting a cook cycle.

Safety warning: Repeatedly resetting breakers without fixing the cause is dangerous. High-voltage components may be shorted.

• Step 1 – Stop using the unit: Do not continue to reset the breaker and attempt operation.
• Step 2 – Visual inspection (qualified persons): Disconnect power and remove the cover. Look for obvious burn marks, melted wiring, or damaged components near the HV section and line filter.
• Step 3 – Component testing: Using a multimeter, test the HV capacitor, diode, and magnetron for shorts per Thermador service specifications.
• Step 4 – Replace failed parts: Replace any shorted component with Thermador-approved parts. Also replace the internal line fuse if blown.
• Step 5 – Verify circuit: Ensure the microwave is on a properly rated circuit and that no other heavy loads share it.

Recommendation: Due to shock risk, have a professional perform these tests and repairs.