About to get some quotes for a new CU.

Any sparks know if a combined up & down ring has to be split to comply with 17th edition ?
Lights are split already but info I can find just says CU needs “configuring to lessen impact”…

Thanks.

There is a maximum square meters a single circuit can cover but from memory (several years since my 17th) you don’t have to split. It all depends on load and diversity. In a modern house this would mean that you would want two circuits.

There is no need to split the ring. The square meterage is a recommendation but as long as you design the circuit balance the loads across the two two legs and meet the Zs requirements for the breaker you’re ok.
The 17th edition requires you to make suitable provision for dividing circuits in a way that doesn’t provide undue risks as a consequence of tripping. Ie a single 30mA rcd as the main switch is not really ideal. I would be looking to ensure lighting circuits are split across RCDs or better still put on RCBOs such that if there is a trip there is still borrowed light from another area of the house.

Rich.

As many as you want on a ring, do not exceed 100M square per circuit.