All people can do is to guess what might be causing the trip to happen - the machine needs diagnosis to find the cause.
Either a leak to Earth is causing the trip - multiple circuits drop out - or an over-current is causing it - just the power circuit trips.
Of passing interest is at what point in time the trip happens - as soon as a programme is selected? As soon as it gets power applied to it - perhaps 10 minutes into the washing cycle - each of these will point towards a particular cause - respectively - Water Inlet Solenoid - Power supply - Heating Element. There are other component areas - pumps - detergent door etc.
It will not be the spray arm - it's plastic and does not connect to the electricity.
A visit from the dishwasher doctor might be a good idea.
Good Luck...
January 2016