Kitchen Configuration

[PrenticeBoyofDerry]

I normally look at this configuration:
Main house:
Upstairs socket
downstairs lights (with smoke alarms)
downstairs sockets (DP isolator to outside socket and spur for intruder alarm)
upstairs lights
Boiler(where ever located)
Garage
Outside lights
Shower (if electric required)
Kitchen:
Above worktop appliances (FCU for under cabinets and FCU for ex-fan)
Below worktop appliances
Cooking appliances (hob/oven)
Freezer if possible.


I do like to keep a least couple of spare ways.
So not unusual to be putting in 12-15 way board.

 

[CHarr]

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

He wants to see more information about intended appliance ratings, but I think the advice is to have:

6mm radial for the (3) ovens + hob ignition & extractor.

4mm radial for washing machine + tumble dryer + dishwasher

2.5mm ring for sockets with spurs to fridge/freezer + boiler

Lighting

The rest of the house is on 2 x rings & 2 x lighting and the CU has capacity for 10 circuits, leaving 2 spare.[/list]

 

[SimonH2]

For the cooker circuit, you need provision for two connection units. Depending on what you fit, each will be either a connection unit or an FCU. The hob for example will most definitely need a fused circuit - though it seems standard for kitchen bodgers to connect them straight to (what for it is) an oversized cooker circuit. However a high powered oven or hob will need an unfused supply.

However, getting 2x6mm cables plus the appliance flex into a connection unit is an interesting challenge. However (and that's something for your spark to design) it might only need to be 4mm cable now you're on MCBs instead of rewireable fuses.


For the main lighting, consider carefully the fittings you use.
Mains frequency flouros with magnetic ballasts are notorious for humming - which will be worse if they are mechanically mounted to wooden cupboards to act as sounding boards. High frequency ballasts should be OK in that respect (as well as starting in a much "cleaner" way) - but can still cause flicker that some people can detect. With any luck, having multiple fittings should mean that the overall effect is largely flicker free.
But overall, I think the effect should be very good - nice even light filling the whole room.

 

[CHarr]

getting 2x6mm cables plus the appliance flex into a connection unit is an interesting challenge. However (and that's something for your spark to design) it might only need to be 4mm cable now you're on MCBs instead of rewireable fuses.

There will be 2 x conventional ovens + a microwave combi-oven. If they are connected on a radial circuit, would there be any need to run 6mm cable beyond the 1st connection unit? If each appliance had its own CU, then I'm guessing that 4mm cable would be OK to continue to 2nd & subsequent? The hob is gas, so the only requirement is to power the ignition, and similarly the extractor fan will only draw a very small current. They might be better connected from fused spurs from the ring (or the fan, even from the lighting circuit?).

 

[riveralt]

However, getting 2x6mm cables plus the appliance flex into a connection unit is an interesting challenge.

http://www.alertelectrical.com/prod...5a-easyfit-dual-appliance-cooker-outlet-plate

 

[riveralt]

There will be 2 x conventional ovens + a microwave combi-oven. If they are connected on a radial circuit, would there be any need to run 6mm cable beyond the 1st connection unit?

No see the above Click mode unit.

If each appliance had its own CU,

I'm sure you don't mean that.

If you use the Click mode unit with an extended double gang back box inset a bit further than normal you can add a single socket next to the Click mode unit for your microwave oven.

Alternatively you can use a single deep single gang back box for the Click mode unit and put a normal double gang back box next to it and feed 2.5mm ² T&E for a double socket taking your gas ignition and your microwave oven.

 

[securespark]

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

The regs advise 2kW+ on their own circuit. Plus, separate circuits for fridge, freezer and boiler.

Oh, hang on, I've added up wrong.... I'd put 2 circuits for appliances plus the three for criticals.

 

[JohnW2]

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?

The regs advise 2kW+ on their own circuit.

Do the regs advise that anywhere other than in Appendix 15 (which is only 'informative'), where they make such a suggestion (only for cookers, ovens and hobs) specifically in relation to ring final circuits (as one of the measures taken to avoid overloading RFC cables). Even in Appendix 15, there is no such comment;/advice in relation to radial finals.

Plus, separate circuits for fridge, freezer and boiler.

Do the regs actually say that?

Oh, hang on, I've added up wrong.... I'd put 2 circuits for appliances plus the three for criticals.

Be that as it may, how often have you seen a 'standard kitchen' which has anything like as many circuits as you were talking about? I'd go as far as suggesting that a substantial proportion of domestic properties don't have as many (or more) circuits for the whole house as you were suggesting for just the kitchen.

Kind Regards, John

 

[securespark]

We obviously don't see eye to eye on this.

What I'm saying is in these cases where the whole house is being rewired and a new board installed, I'd like to think the electrician would plan for the future (and the now, seeing as in this particular case he is aware a new kitchen is looming).

Do the regs actually say that?

In view of this and the fact that the regs do say segregate stuff as much as possible so as to avoid inconvenience etcetera...., plus Appx 15, it makes sense to separate these appliances, not only from a loading POV, but so that if in the future a fault occurs, he doesn't wind up with a whole heap of appliances going off.

You can appreciate that if a tripping occurs, it would be far better to have critical appliances like the fridge, freezer and boiler unaffected by it?

how often have you seen a 'standard kitchen' which has anything like as many circuits as you were talking about?

Believe it or not, I have seen a few!

 

[JohnW2]

We obviously don't see eye to eye on this. What I'm saying is in these cases where the whole house is being rewired and a new board installed, I'd like to think the electrician would plan for the future ....

I wouldn't say that we don't see eye to eye - one can obviously produce arguments for having virtually every significant load on its own dedicated circuit. The point I was making was (perhaps just because of my limited experience), I've never seen or heard of anyone having anything like as many circuits as you've been suggesting in a 'standard' domestic kitchen - even though you say that you have.

... the regs do say segregate stuff as much as possible so as to avoid inconvenience etcetera...., plus Appx 15, it makes sense to separate these appliances, not only from a loading POV, but so that if in the future a fault occurs, he doesn't wind up with a whole heap of appliances going off. ... You can appreciate that if a tripping occurs, it would be far better to have critical appliances like the fridge, freezer and boiler unaffected by it?

Sure, those are the considerations I mentioned above. Having said that, I personally think that the arguments about segregation to 'avoid inconvenience' are perhaps overplayed, particularly given the rarity of the situations we're talking about. It certainly makes sense, from the safety viewpoint, to have lighting segregated (e.g. RCD-wise) from other circuits in the same part of the house. It also probably makes sense to have a freezer on a dedicated circuit when a house is unoccupied for appreciable periods - although, as we've often discussed, when a house is occupied, unless there are alarms having a freezer on a dedicated circuit (particularly if it's in a garage, cellar or whatever, and particularly if it is RCD/RCBO-protected) may actually be counter-productive, so even that is not totally clear-cut. In most other situations, IMO, it really is a matter of 'convenience' in the literal sense (even,usually, for fridges and boilers), and I wonder how much effort and cost in relation to the electrical installation is really justified in order to avoid very occasional 'inconveniences'.

Kind Regards, John

 

[securespark]

That's exactly my point.

Where the job is a rewire, it's not a great deal more effort, or cable or whatever to run another circuit in or double up on a cable run, or whatever.

 

[JohnW2]

... I wonder how much effort and cost in relation to the electrical installation is really justified in order to avoid very occasional 'inconveniences'.

That's exactly my point. Where the job is a rewire, it's not a great deal more effort, or cable or whatever to run another circuit in or double up on a cable run, or whatever.

Hmmm. Interesting - we seem to be 'making the same point' but with opposite interpretations

It's obviously just a judgement regarding the balance between time/effort/cost (even if you think it may be small) and the 'avoidance of very occasional inconvenience' - so I guess it's inevitable that different people will come up for different answers.

FWIW, I don't recall (certainly not in the 26 years I've been in my present house) anything in my kitchen (or utility room) other than an (abused!) toaster ever having resulted in any protective device operating and 'taking out' anything else ... so, in my case, the level of 'inconvenience' to be reduced by having a large number of circuits is already incredibly low. ... and all I have is one general sockets ring (also serving D/W and a small fridge), a radial for W/M and dryer, and a radial serving a couple of sockets (one for a microwave) (freezer is elsewhere )

Kind Regards, John

 

[securespark]

Well, that's just it. The time/ effort/ cost is low when you're doing a rewire anyway.

And if you have a fault, it's well worth having things like the boiler on its own circuit when all else is off.

 

[JohnW2]

Well, that's just it. The time/ effort/ cost is low when you're doing a rewire anyway.

Yes, fairly low - but, as I said, one has to make a judgment as to whether even that fairly low cost is justified in order to avoid what will probably be minor inconveniences occuring extremely rarely. As I said, opinions/judgements will obviously vary.

And if you have a fault, it's well worth having things like the boiler on its own circuit when all else is off.

As above, it's an individual judgment call, based on consdierations of 'cost' (widest sense) vs. inconvenience. In the final analysis, one could obviously minimise the risk of any inconvenince by having every load on a seperate circuit.

Kind Regards, John

 

[securespark]

Yes, you could....

But I only do this for criticals.