We have a stand alone Ikea induction hob which is rated at 2kW. Have had no problem with it tripping the circuit breaker when used on its own. However, if using the electric kettle (1.5kW) at the same time it will occasional trip. It is the circuit breaker for the ring main which trips and not the RCD for all the mains electrics. So presumably 3.5kW is at the upper limit of its rating. Switching it off and then back on resets it.