Some Electrics Have Stopped Working

[Murdoch]

Switch each circuit on, about 1 minute apart

Have you unplugged everything?
What where you using when it tripped

 

[poni]

could be a neutral to earth fault, i would normally be looking for water ingress ,but as we are going into a drought, this is unlikely,
if its a neutral you will not find it by turning off single pole MCB's , you will need an electrician,

 

[monkey5]

You need to physically unplug all plugs on the circuits that not working, not just switch off, actually unplug all you can, if you have a boiler or hot water tank with an immersion they should have a switch with a fuse In so turn them off, then try the breakers then, if it stays up, plug one thing in at a time with probably a couple of minute in between each and see if anything trips it. Then might help narrow it down, 9 times out of 10 I find it's an appliance if it's just happened rather than any work being done.
Is the garage fed from the circuit not working, if so id turn off the main switch in there too just to illuminate that.
Let us know how you get on.

 

[ProDave]

It is probably a neutral fault somewhere. In which case turning off individual breakers will not help identify it. Probably time for an electrician.

One last test, go round and unplug absolutely EVERYTHING in the house yes all the hidden behind something sockets as well, and see if it will reset, just to make sure it is not a faulty appliance plugged in.

 

[Mike P]

So, it’s either a Neutral earth fault of one of those circuits or possibly a faulty RCD.

 

[michael8554]

The RCD trips when the Earth Leakage, as MCBs 8, 9, 10, 11, 12 are switched on, exceeds the RCD 30mA rating.

So without 8 (the cooker) and/or 12 (the outside?) the RCD doesn't trip.

I'd try resetting 9, 10, 11, 12 (not 8) and leave for a while.

If that's okay, try 8, 9, 10, 11 (not 12).

And then 8, 10, 11, 12 (not 9).

Then if one MCB is now suspected, try with all the switches and devices on that circuit disconnected/switched off.

Or RCD on the right is faulty ?