Kitchen Configuration

[CHarr]

I'm seeing my electrical contractor tomorrow. He has been rewiring our 'new' 1950s house (for the first time!), and has already renewed all the cabling to the lights and plugs, and will be fitting the consumer unit. That will complete phase 1 of our refurbishment.

The next phase is that we are about to start work on what amounts to a garage conversion to provide a new kitchen, and the builder has specifically excluded electrical works, knowing that we already have someone doing the rewire. We have settled on the kitchen design, and I'd welcome some views on the likely wiring configuration before my discussion with the contractor tomorrow:

Cooking Appliances: Two ovens (both described as needing wired-in installation with 13A fuses) + combi-microwave (just says 13A fuse) + gas hob (for ignition only).

Other appliances: Fridge, freezer, washer, dryer, dishwasher, cooker extractor, boiler.

Sockets 4 x Doubles

Lighting.

I'm guessing that the cooker circuit would be 6mm cable, but wonder whether the appliances need individual protection. I'd expect to put the washer, dryer & dishwasher on a separate circuit and I'd like to be able to use all three at the same time without risking tripping out the supply to the freezer! The other appliances (which won't draw very much) could be on a second circuit, along with the sockets (for counter-top appliances etc.).

Does this sound OK?

Lastly lights: the kitchen will have a vaulted ceiling, and we don't want fittings in the ceiling itself. Instead, we are planning uplighters on top of the kitchen cupboards (there will be about ten of them), throwing light up into the ceiling space to be reflected down, together with downlighters under the cupboards lighting work surfaces. We would like them switched from a two-gang light switch, but have no idea how the wiring would be organised for such a setup.

 

[securespark]

It would be helpful to have the loadings of the cooking appliances.

In an ideal world, each appliance over 2kW would have its own circuit, but that depends on whether the electrician has fitted a big enough board.

In your list, I would give the fridge, freezer and boiler their own circuits for convenience and all the appliances that are 2+kW also, totalling 9. But, if you've only got a 10 way board, that's an issue...

It would be nice to think he had fitted a board with room to spare, knowing you were planning a new kitchen.

Are you going to supplement the lighting with under-cupboard lighting too?

When you say "on top" of the wall units, are these wall-mounted fittings?

 

[CHarr]

It would be helpful to have the loadings of the cooking appliances.

In an ideal world, each appliance over 2kW would have its own circuit, but that depends on whether the electrician has fitted a big enough board.

In your list, I would give the fridge, freezer and boiler their own circuits for convenience and all the appliances that are 2+kW also, totalling 9. But, if you've only got a 10 way board, that's an issue...

It would be nice to think he had fitted a board with room to spare, knowing you were planning a new kitchen.

Are you going to supplement the lighting with under-cupboard lighting too?

When you say "on top" of the wall units, are these wall-mounted fittings?

In reverse order, we are using 233cm high cupboards on a 240cm wall, so I was planning to mount the uplighters on the cupboards themselves, just behind the cornice (so they will be invisible). The ceiling is vaulted, and slopes at 35 degrees, and is so high at the centre, that it would be completely inaccessible to change bulbs with conventional fittings without a very large pair of steps! Downlighters too, under the cupboards.

I don't know what size board he is fitting, but the rest of the house has 2 x rings + lighting. I've never encountered separate circuits for individual appliances. Our current (modern house) doesn't have them in the kitchen. Everything except the cooker is on a ring main with 13A sockets, and only the boiler is on a fused spur (I haven't checked, but I think it is a spur).

I don't have the individual cooking appliance loads, but the ovens (2 x identical) both have multi-function features and built in grills, but if the manufacturer suggests 13A fuses, I assume the maximum load is c3kW.

 

[PrenticeBoyofDerry]

I would supply separate circuit for your cooking appliances, even if you are intending loads not exceeding 13A, I would make provision for upgrades to higher output appliances. The cable size would depend on potential load, route and distance of cable, as de-rating factors may need applying.
Then a separate 32A circuits for appliance below worktop and above worktop.
Plus separate circuit for main lighting, under cabinet lighting can taken form above counter socket circuit via fused spurs or taken from main lighting circuit.

 

[CHarr]

I would supply separate circuit for your cooking appliances, even if you are intending loads not exceeding 13A, I would make provision for upgrades to higher output appliances. The cable size would depend on potential load, route and distance of cable, as de-rating factors may need applying.
Then a separate 32A circuits for appliance below worktop and above worktop.
Plus separate circuit for main lighting, under cabinet lighting can taken form above counter socket circuit via fused spurs or taken from main lighting circuit.

I'm sorry, but you have confused me. Do you mean separate circuits for each cooking appliance, or one for all four? (You wrote circuit, not circuits).

If all the under-worktop appliances were on a 32A ring, does that mean that the maximum combined load could be 7.3kW (32A x 230V)?

 

[PrenticeBoyofDerry]

Cooking appliance=oven and hob (exclude microwave)

 

[PrenticeBoyofDerry]

If all the under-worktop appliances were on a 32A ring, does that mean that the maximum combined load could be 7.3kW (32A x 230V)?

I simple terms yes.
I would also consider looking at your set up, having the boiler on it's own circuit via RCBO and even maybe the freezer.

 

[riveralt]

Put your cooker circuit on its own radial 6mm ² T&E with a 32A MCB or better still RCBO.
Put you kitchen on a 32A (MCB/RCBO) ring final circuit - tap of the kitchen RFC for you individual appliances using a grid switch system using 20A dual pole switches - thereby enabling you to isolate each appliance from the circuit.
If space in your CU allows put the kitchen lighting on its own 6A (MCB/RCBO) circuit - otherwise tap into the existing downstairs circuit.

In most cases given your ceiling design you cannot fit anything other than surface mounted lighting on the ceiling so your suggestion is okay.
Wiring will be for the electrician to worry about not yourself - for lighting it can get a little bit complicated but once you understand the principles it is relatively easy.
Have you thought about wall mounted track lights - especially when used with LED's - they can give a good spread of light and will support you under cupboard lighting.

 

[OwainDIYer]

Lastly lights: the kitchen will have a vaulted ceiling, and we don't want fittings in the ceiling itself. Instead, we are planning uplighters on top of the kitchen cupboards (there will be about ten of them), throwing light up into the ceiling space to be reflected down, together with downlighters under the cupboards lighting work surfaces.

continuus slimline fluorescent tubes would give more even light and be cheaper to run.

 

[winston1]

[/quote]


If all the under-worktop appliances were on a 32A ring, does that mean that the maximum combined load could be 7.3kW (32A x 230V)?[/quote]

Not quite. UK mains is 240V (measure it, only the arse sitters in Brussels think it is 230V). So max load is 7.68Kw.

If the washer, dryer, and dishwasher were all running at the same time it could well exceed this. Put the washer and dryer on one circuit and the dishwasher on another, say the above counter ring.

 

[echoes]

Put you kitchen on a 32A (MCB/RCBO) ring final circuit - tap of the kitchen RFC for you individual appliances using a grid switch system using 20A dual pole switches - thereby enabling you to isolate each appliance from the circuit.

Or a 32 A radial.

 

[JohnW2]

In your list, I would give the fridge, freezer and boiler their own circuits for convenience and all the appliances that are 2+kW also, totalling 9. But, if you've only got a 10 way board, that's an issue...

Have I got this right? Are you actually suggesting 9 circuits (I think 10, once you've included the sockets, and maybe 11 if the kitchen is to have its own lighting circuit) for what sounds like a pretty standard kitchen?

Kind Regards, John

 

[CHarr]

I'm just about to go over to the house for my discussion with the electrical contractor. I'll post his recommendations later.

 

[PrenticeBoyofDerry]

If the washer, dryer, and dishwasher were all running at the same time it could well exceed this. Put the washer and dryer on one circuit and the dishwasher on another, say the above counter ring.

I think a 32A ring/radial could quiet easily deal with the load of those appliances without any issues.

 

[bernardgreen]

It is sensible to have kitchen lighting and kitchen power on different RCDs.

Then if there is an accident that trips the power RCD you will still have lights to see to deal with the aftermath of the accident which may include having to give first aid for burns, scald or electrocution.