Chris at eSpares says...

After your appliance has ran for around sixteen hours it needs to auto defrost. At this point it stops the compressor and fan and turns on the defrost heater. These heaters can fail and cause the tripping of the house earth trip. If this is occurring suspect the heater element. This is 'pushed' into the evaporator bracket and 'pinched in' to remove use a pair of side cutters to gently open the evaporator mounts and pinch back when fitted.