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

Former Community Member
Former Community Member
Can I have an opinion please?


Now I fully understand this is not correct but struggling to code it.  I have just conducted an EICR on a domestic property.

The old cooker circuit (32A Type B on 30mA RCD) has at some part of its length, been turned into a very small 2.5mm final ring circuit. 

The end to end values would return an R1+R2 of 0.22 Ohms and the furthest socket back to the consumer unit has an R1+R2 of 0.41Ohms.

I know it's wrong, but cannot (apart from the connection being inaccessible) actually pinpoint how to code it and why.


Thoughts please?




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  • 0
    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.
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  • 0
    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.
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