A ringless design... your thoughts please?

[Hibbo]

When I (if I ever get round to it) renovate my flat, I am not planning on using any ring final circuits, radials only. I'm sure a radial for sockets on a B20 RCBO will be fine (only two bedrooms and a living room), I'll run a 6mm/32A cooker circuit for possible future use, although I cook with gas.
Now for the kitchen, how does this sound:
a radial for appliances (washing machine, dishwasher (maybe!), fridgefreezer) and combi boiler on a B20 MCB (non-RCD cabling options t.b.c.)
a radial for kitchen sockets on a B20 RCBO

Does this sound OK? Does 20amps sound sufficient for kitchen sockets if the main appliances are powered separately?

Cheers

PS. All 20amp circuits will be in 2.5mm^2 T&E

 

[securespark]

There's no harm in using 4mm² radials on a 32A device.

 

[ricicle]

There's no harm in using 4mm² radials on a 32A device.

Although you might want to choose accessories that will accomodate 2 x 4mm² cables !

 

[Hibbo]

There's no harm in using 4mm² radials on a 32A device.

Although you might want to choose accessories that will accomodate 2 x 4mm² cables !

That's one of the reasons I'm sticking with 2.5mm/20amp. The other being that it makes any future additions so much easier, no need to mess around extending rings or utilising contrived allowances within the regs...

 

[plugwash]

Washing machines and dishwashers often come bloody close to (some may even exceed) the full 13A, I would not want to put both of them on the same 20A radial.

 

[mikhailfaradayski]

why don't you add up the power of the kitchen appliances you expect to use and make a judgement on whether 1 radial will suffice?

Maybe go a little further and supply the boiler from its own radial. If you plan to replace the C/U, there'll probably be plenty of space for additional mcb's

IMO your suggestion should be fine, ring finals are becoming increasingly un-necessary with greater circuit segregation in a modern C/U.

 

[Taylortwocities]

Maybe go a little further and supply the boiler from its own radial. If you plan to replace the C/U, there'll probably be plenty of space for additional mcb's

I

err, why? The boiler wil only pull a couple of amps. You need to concentrate on the power-hungry devices
Dishwasher
wash machine
tumble dryer
Hob
Oven
etc
etc

 

[mikhailfaradayski]

Maybe go a little further and supply the boiler from its own radial. If you plan to replace the C/U, there'll probably be plenty of space for additional mcb's

I

err, why? The boiler wil only pull a couple of amps. You need to concentrate on the power-hungry devices
Dishwasher
wash machine
tumble dryer
Hob
Oven
etc
etc

Im aware of that, but the idea was so he can keep heat and hot water in the flat in the event of one of his appliances goes belly up

 

[Paul_C]

Washing machines and dishwashers often come bloody close to (some may even exceed) the full 13A, I would not want to put both of them on the same 20A radial.

Agree on that one entirely. Do what is done in many other countries, and run a dedicated circuit for each of these major appliances.

A single 20A radial for the remainder of the kitchen may then suffice, but consider that many of the power-hungry appliances are likely to be in use simultaneously. Microwave oven, toaster, kettle etc. - Fairly easy to fully load a 20A circuit with those. I'd consider splitting the outlets between two circuits.

 

[Hibbo]

Thanks for the responses,

I understand what you mean aboot loading, and of course a separate circuit for each appliance (a la Johnny Foreigner) is the best way, but as I'm going to be using an all RCBO setup costs could quickly escalate.

Of course, with everything on, each 20A radial would be overloaded, but this would also be the case on a 32A ring. How many kitchens have W/M, D/W, kettle, microwave, health grill, toaster, (deep-fat fryer up here too!) etc all on a 32A ring? Lots I reckon, but due to the unlikelihood of everything being on at the same time (and most things being used for a short time only) this doesn't seem to be an issue.

As for losing the boiler, whilst I am determined to have the boiler non-RCD, I find it nearly impossible that a switched-off appliance could trip an MCB whilst I'm away thus losing the boiler.



Ah well, maybe I'll go back to a split load + RCBO(s) CU plan and run extra circuits to the kitchen.

(I've even thought about running a submain to the kitchen and having a flush mounted CU on the wall in there, but I think that's massive overkill for a wee flat like this!

 

[AndyPRK]

People get away with 32A on a kitchen as it is sensible.

That doesn't mean you will get away with 20A !

As said, only have 2 appliances on at the same time has potential to put it over the limit.

Why don't you either

a) Use a 2.5m ring
b) Use a 4mm radial
c) Use a 6mm radial

(for the kitchen only)

 

[SparkyNinja]

Why not install a 32Amp radial to a grid switch bank?

 

[1john]

I would opt for a 4mm radial circuit for the appliances to a grid switch and a 4mm radial for the sockets. Or have half sockets / appliances on one 4mm radial and the other half on another. Having the boiler on an individual, circuit is a good idea in my book too.

 

[ebee]

Why not run a ring final?

 

[Hibbo]

Why not run a ring final?

Because that would be too easy!


I am leaning towards 25A/4mm radials - will I get 2x4mm cables in to an MK Logic accessory?