The first thing to
do is test the RCD, you can do this by turning off your main switch and try
to reset the RCD or RCCB, if it does not reset you will need to
call a Electrician, if it does reset go to step
of your appliances, this is unplug not just turn off (don't forget your dish
washer, InSinkErator, rang hood, ect) Turn the main switch back on and Try to reset if the RCD resets the start
plugging the appliance back in until you find the one that trips the RCD.
Make shore you do not have any pumps, leads, lights plugs into outdoor
If non of the above helps then you will need to call a Electrician.