CU Replacement - Upstairs and Downstairs Rings Connected

[SW1970]

Hi, newbie here. Done a domestic PIR and Consumer Unit replacement is required (damaged, lighting circuit not earthed or RCDd, plus other reasons). However, another finding was that the upstairs and downstairs ring final circuits are connected (currently installed as the 2 live cables going into the circuit breaker).

Cable size is 2.5mm2.
Total floor area served is 85m2.
Circuit breaker is 32A (RCD protected).

After finding out rings were connected I did cross connected line conductor resistance test at each socket and it looks like the rings are connected at the extremity and not bridged half way round. I've deduced this as the resistance readings are almost identical to within 0.01ohm.

Customer doesn't want to fund sorting out the rings (tricky as laminate flooring and fitted furniture everywhere).

I'd appreciate views on whether it OK to proceed with CU replacement and re-energise with the rings remaining connected as they are now? Clearly it doesn't meet the suitable segregation of circuits requirement, but this appears to be the only failing. Any thoughts?

Many thanks
SW

 

[Octopus]

How many circuits are there in the house in total? If there aren't many maybe you should go down the RCBO route.

 

[topquark]

Are you sure it's two rings connected. Many older houses only had one RFC.

 

[SW1970]

Hi, CU replacement is required anyway because the existing one is damaged, but circuits are:

Cooker
Downstairs lights
Upstairs lights
Garage lights
Garage sockets
Upstairs and downstairs sockets
Utility room sockets

Cheers
SW

 

[SW1970]

Topquark - could be. House is 1963 build. Utility room is an extension so that would explain why it's on a separate circuit.

 

[Octopus]

I'd talk to the customer about a set of RCBO's, rather than a dual RCD unit.

 

[topquark]

As your readings are all pretty much identical my first guess would be only one ring. How many cores do you have back at the CU?

 

[Des 56]

As your readings are all pretty much identical my first guess would be only one ring. How many cores do you have back at the CU?

(currently installed as the 2 live cables going into the circuit breaker).
SW
Same question as topquark,
I dont quite get what that description is suggesting

 

[Guest123]

Definitely sounds like a single ring final serving up & down.

 

[SW1970]

Two 2.5mm2 cores going into the MCB labelled sockets upstairs and downstairs. So if it is a single ring installation, ok to proceed with CU replacement and identify the segregation deviation from BS7671? Cheers, SW