Washing machine

Sounds like you may have a corrosion issue or water ingress, causing a short. Could be a corroded heater, water in the main control board, water in the pump motor - the list is endless. Most washers tend to run the pump to ensure drum is drained before starting the cycle, so it would be probable that the problem is in the pump area.

You don't say if the main switch is an RCD or an ELB. I presume it's an RCD.