6mmT&E Radial - 2.5mm T&E Ring

I'd suggest that while it's somewhat unconventional, it's not "wrong".  I could be looked at as a 6mm sub-main feeding a 32A MCB, which then feeds a conventional ring - but that the ring's MCB has been omitted as upstream devices already give sufficient protection (as permitted by BS 7671).


Actually it's not that unconventional anyway - that arrangement is quite common both in kitchens (converted cooker circuit) and in IT classrooms where a single point of isolation is wanted for all the sockets in a room (radial to isolator, then ring to the sockets), and often termed a "lollipop" circuit.


Testing wise, it's probably easiest to treat as two distinct circuits - a radial feeding a ring.


   - Andy.

It is a lollipop/ lassoo  circuit, quite common in just this situation, even if  not one of the examples in the annex of BS7671..

Not 'wrong' as such, and no  code required if done neatly; unless it is showing signs of thermal distress, given  as you have shown, the Zs and so on checks out.

The same sort of rules that govern a ring apply, just the fuse is further back. you;ll do ring-round tests from a socket, but R2 back to the board.


Of course if the joints are taped choc block and hanging out the wall then its a C2...

Mike.

Mike,


Thanks buddy - Brill

Andy,


Many thanks buddy - every day is a school day!

A ring final circuit is defined in BS 7671 as  "a final circuit arranged in the form of a ring and connected to a single point of supply", and 433.1.204 allows accessories to be supplied via a ring circuit with >=2.5mm, 30/32A protection etc. Since the load end of the 6mm cable could count as a single point of supply, that seems to tick all the boxes.