Two rings in one room

[Amp David]

Absolutely agree, where do you stop?
If someone opens up a socket then they should be able to confirm isolation.

Glad to see someone else thinking the same

 

[Amp David]

We Still need to protect those who may switch off the breaker for one ring, test one socket in the room with a plug tester then treat all the sockets as dead. Remember you also might do a proper isolation on one board and not realise that some of the sockets are being fed by the installation next door. Nothing will show up on the board you have proven dead

Thats why you would prove dead at the point you are working at. Not just one socket, but every one you work at. Thats why locking of is a good idea too