1.Turn off all Sockets and light switch.

2.Unplug all appliances ( Fridge, Washing machine, Kettle etc. )

3.Turn off all MCB’s

Try to Reset RCD (turn ON)

If it is ON mean one of appliance faulty (try to connect appliance one by one and find faulty appliances)

Otherwise still tripping then wiring fault (call qualified electrician to find fault).