If the trip that goes is the big one that switches off lights and sockets then it indicates an electrical fault where some current is going where it shouldn't - like to earth - an unsafe condition.
If the trip that goes is a smaller single-pole switch that just takes down all or just some of your power sockets then it's current overload. Might be too many devices on that circuit for the rating of the MCB (breaker) or it could be a fault in the dryer itself taking too much current - what's in a dryer? Drum motor, air blower and heating element - possibly one of those.
Does the trip go each time you use the dryer or just some of the time? What else is in use when it does trip?
Peccavi, December 2008
