Could be the heating element - depends on when the trip trips (at which point in the washing cycle) - Usually a WM fills with water before the heating element is turned on - try a cold wash if you can & see what happens.
If the Trip takes out just a group of power sockets then it's an overcurrent problem - if the trip takes out the whole house - lights and power - then it's a potentially unsafe condition.
Peccavi, May 2009
