RCD-protected circuit that is not on a separate breaker

[ericmark]

Then I turn ON the second RCD and the loft sockets come up (all MCBs are still OFF). Is that normal?

No not normal, it would seem likely there is a fault, as @flameport says, but with my own house, can turn off all RCBO's and the freezers and fridge/freezers still work, and central heating still works, there are always exceptions to the rule, but seems more likely there is a fault.

 

[davelx]

No not normal, it would seem likely there is a fault, as @flameport says, but with my own house, can turn off all RCBO's and the freezers and fridge/freezers still work, and central heating still works, there are always exceptions to the rule, but seems more likely there is a fault.

Yes, but if you turn off all RCBOs AND MCBs surely nothing works? If something does then you have a similar problem!!!

 

[DetlefSchmitz]

Eric has a UPS.

 

[ericmark]

Eric has a UPS.

Yes and as you rightly say this is why

Yes, but if you turn off all RCBOs AND MCBs surely nothing works? If something does then you have a similar problem!!!

Is not true, all RCBO's all isolators, and all MCB's off and 4 sockets and a FCU still works, and I feel I do have a problem as the button I need to press to switch it off has no provision to lock it off, but I also have a certificate to say it is compliant.

I am reasonably sure @RookieTony also has a problem, however there may be an overload device within the required 3 meters from the CU we are unaware of.

So all we can say is it requires investigation.