Oven trips the household breaker or RCD as soon as it is turned on or when heating starts

Safety first: Turn off power at the main breaker. Do not repeatedly reset a tripping breaker without finding the cause.

• Isolate elements: Disconnect one heating element at a time (bake, grill, convection) and test the oven. If the breaker no longer trips with a particular element disconnected, that element is likely shorted and must be replaced.
• Insulation check: Visually inspect wiring looms for melted insulation or pinched wires against sharp metal edges. Repair or replace damaged sections and secure with high-temperature cable ties.
• Check for moisture: If the oven was recently cleaned with excessive water or steam, allow it to dry thoroughly (door open, 24 hours) before retesting.
• EMI filter: Inspect the mains interference filter (usually near the terminal block) for burn marks or cracking. Replace if suspect.
• Test carefully: After repairs, restore power and test each heating function separately to confirm the fault is resolved.