Hello Everyone and I'm new to the Site so Greetings and hope your'e all well.

I've recently moved house. The rings are continuous but the drops to most sockets (apart from the kitchen) are spurs via JB's with a single 2.5T&E drop in 16mm oval conduit. I'd figured on a certain amount of re-wiring anyway but as opposed to re-chasing and new conduit, which I've done before, I had the idea of jointing the 16mm oval via a 20mm extender/convertor to a circular conduit box and running in single core 2.5mm thereby removing the spurs and making each socket part of the continuous ring. I'd continue the runs in 20mm conduit/ single 2.5mm covering all the affected sockets which aren't many. Any new sockets could be added via 2.5 T&E and appropriate conduit. I calculate 2.5mm single stranded cable in less than 3metre straight 16mm conduit runs has a cable factor of 43 and 6 cables x 43 gives 258 which seems suitable for 16mm conduit which has a cable factor of 290.

Just a couple of notes:- The existing 16mm oval conduit protrudes above the plasterboard into the loft and the 2.5mm existing ring is 2.5 with a 1.5mm CPC. The 16mm conduit is continuous into the socket backboxes. It's a dormer bungalow and all the upstairs sockets are on internal stud walls so can be easily converted using 2.5T&E. The kitchen has already been re-wired.

Any comments or suggestions welcome as I've always chased out and replaced conduit in the past.

Best regards,

Michael