The first step is understanding if the problem is the socket or the appliance. Find an extension long enough to reach a different socket. Move the appliance to reach the power cord, and connect the dishwasher to a different power socket.
If the dishwasher does not trip the circuit breaker using a different power socket, then the problem is the power socket.
If the appliance still trips the circuit breaker, then there is an internal short.
The power cord is the first part to inspect. A test can be done using a multimeter like this:Multimeter.
With power cord not connected, with appliance off, and the multimeter set on impedance (Ohms), touch the prongs of the power plug and read impedance. Impedance must be infinity. If there is low impedance, then the power cord is shorted.
Since the problem happens immediately when you start the washer, there are few more parts that can be responsible. After testing power cord the main control unit must be tested. This is an electronic board enclosed in a plastic box. The control unit is part of the door assembly. When there is a short that is tripping the circuit breaker it is usually possible to spot burnt areas at the control board contacts or components.
If the circuit breaker trips shortly after starting dishwasher (one second or two), then the inlet valve located at the back of the appliance must also be tested.
Start checking if the problem is the power cord or the wall-socket. If problem is the appliance check warranty status by calling the number listed on the owners manual.