How to isolate a wiring
Your fuse box will contain either miniature circuit breakers (MCBs) or rewirable fuses.
With the trip switch on and the fuse box switched off, switch off all the MCBs or remove all the fuses in the fuse box.
Switch on each MCB replace each fuse one by one, making sure you switch off the fuse box each time you switch on an MCB or replace a fuse.
Once you have switched on an MCB or replaced a fuse, turn the fuse box back on and check if the trip switch operates.
If the trip switch does not operate, continue to switch off the fuse box and switch on the next MCB or replace the next fuse. The faulty circuit will eventually cause the trip switch to operate again.
When this happens, turn the fuse box off. Turn off the last MCB or remove the last fuse and turn the tripswitch back on. Leave this MCB switched off or fuse out and restore the rest.
You will now need to unplug everything on the circuit that you have isolated as being faulty and turn the fuse box off.
When you have unplugged all the appliances on the remaining circuit you should switch on the MCB or replace the fuse of the faulty circuit and then turn the fusebox back on.
If the trip switch trips it is possible there could still be something plugged in on that circuit, or there could be a fault with the wiring on that circuit.
When you have reset the trip switch with all the MCB's switched on and the fuses replaced, you should plug the appliances on one by one.
When the trip switch trips again, the last appliance you plugged in should be isolated and the trip reset.