Electric oven

It is very unlikely to be the thermostat. A thermostat is just a mechanical/electronic switch that regulates temperature, so it rarely breaks down under heat to create an earth fault. Most Likely Causes: Faulty Heating Element (Most Common): The bake, grill, or fan element expands as it heats up. Micro-cracks in its casing allow current to leak to earth under thermal expansion, tripping the RCD. Moisture in Element: If the oven is new or unused for a while, trapped moisture inside the element's insulation lowers resistance and trips the RCD as it warms. Cooling Fan Motor: The cooling fan kicks in once the oven reaches a set temperature. A shorted fan motor will trip the circuit as soon as it gets powered. Next Steps: Isolate the oven and carry out an insulation resistance (IR) test on each heating element to confirm earth leakage before replacing parts.

It could be the thermostat, but if the oven trips only when it gets warm, the fault could also be with the heating element or another component breaking down under heat. It would need proper electrical testing before replacing any parts. I’d recommend keeping the oven switched off until it has been checked by a qualified electrician or appliance engineer.