Indesit oven trips the RCD only after it has been heating for some time, not immediately.

Safety warning: Repeated RCD tripping indicates a potentially dangerous earth leakage fault.

• 1. Dry out elements: Sometimes moisture in elements can cause intermittent tripping. With the oven empty, heat at low temperature (e.g. 100°C) for 30–40 minutes under supervision. If tripping worsens, stop and proceed to testing.
• 2. Test elements cold and hot: With power off, disconnect each element and test insulation to earth with a megohmmeter. If possible, repeat after gently heating the element with a hot air gun. Replace any element with low insulation resistance.
• 3. Inspect high-heat wiring: Check wiring near elements and the top of the cavity for brittle or cracked insulation. Replace with high-temperature cable as needed.
• 4. Check mains filter: Replace the mains interference filter if there are signs of cracking or if insulation tests point to it as the source.