Oven trips the household circuit breaker or RCD as soon as heating is started.

Safety first: Do not repeatedly reset a tripping breaker. Disconnect the oven and verify no power is present before testing. Only qualified persons should perform insulation resistance tests.

• Visual inspection: Remove rear and top covers. Look for burnt wires, melted insulation, or signs of arcing to the metal chassis.
• Isolate elements: Disconnect each heating element in turn and test the oven. If the breaker no longer trips with a particular element disconnected, that element is likely leaking to earth and must be replaced.
• Insulation test: Use a megohmmeter (if available) to test insulation resistance between each element terminal and earth. Low resistance indicates a fault.
• Check mains filter: Inspect the EMI filter module for cracks or burn marks. Replace if suspect.
• Drying moisture: If the oven was recently cleaned with excessive water or steam, allow it to dry thoroughly for 24 hours before retesting.