17th edition CU arrangement

[Yanni]

I've got the following circuits in a small terraced 1906 house and I'm in the middle of a rewire.

1. Downstairs lights
2. Upstairs lights( includes staircase light)
3. Downstairs ring
4. Upstairs ring
5. Washing machine( Also feeding Cooker hood and boiler via an MK grid )
6. Cooker


Downstairs ring feeds kitchen and fridge.

Could someone help me group these circuits on a 17th edition CU ?

Last rewire I did was on a split load 16th edition so not greatle familiar with 17th edition arrangement.

 

[nozspark]

Something like......

MAIN SWITCH

RCBO Smokes

RCD1
D/S sockets
Washing machine sockets
U/S Lights

RCD2
U/S sockets
Cooker
D/S Lights

 

[ericmark]

The bit everyone is looking at is:-
(iii) take account of danger that may arise from the failure of a single circuit such as a lighting circuit.
(iv) reduce the possibility of unwanted tripping of RCDs due to excessive protective conductor currents produced by equipment in normal operation.

Most people put upstairs lights with all other down stairs circuits except for downstairs lights.

And downstairs lights with all upstairs power circuits.

Although this is norm it is not always correct. After having twin RCD on my house for last 18 years if redoing I would not group lights with sockets and all sockets would be on RCBO's

In your case with only 6 circuits I would use all RCBO's unless you have used Ali-tube cable then maybe MCB on downstairs lights?

 

[Yanni]

Thanks a lot ericmark. I think ideally I would have all circuits on RCBOs but I bought a split load MK CU last year and didn't realise that they would sell RCBOs for £30+ each !

I think I will go for what nozspark suggested and it might be cheaper to buy a new 17th edition CU. It is a buy to let property anyway.