Kitchen Installation

Hi, I'm new here.

I'm planning a kitchen installation, going to install electric oven, gas hob, cooker hood, fridge, separate freezer, possibly under cabinet lights. My plan is as follows, I'd welcome any comments and criticisms please!

Electric oven & gas hob
2500W oven, so planning a 16A radial from CU to cooker outlet in 2.5mm t&e.
Both hob (for igniter) and oven will be hard wired into the cooker outlet plate.
There will be a fcu above worktop level adjacent to hob containing 13amp fuse
Wiring will probably be surface run under cupboards, but chased into wall behind tiles for the fcu
Due to the short length of concealed wiring, as I understand current regs the cable needs to be RCD protected, so planning a 16A type B RCBO supplying only that radial

Fridge & Freezer
Dedicated radial supplying both appliances in 2.5mm t&e from 16A RCBO via 13A fcu above worktop level
Unsure from research whether f/f on rcd is a good idea, but due to concealed wiring to fcu I don't have much choice unless I start burying steel pipe in the walls.

Cooker hood
Spur from ring main, to fcu located in kitchen cabinet adjacent to hood, hood hardwired to this

Under cabinet lights
Haven't really thought about this yet, I think only option is to take a new run from existing lighting circuit? It'd be much easier to use the ring main but not sure this would be allowed?

Thanks!
Richard

What do you plan to do about testing?

Do you know what tests you would carry out on the new and modified circuits - what sequence you'd do them in and at what point you would energise them, and for each test do you know what is being measured, why it is important, how you would carry out the test, and with what equipment, and what sort of results you would expect to get if everything was OK?

Hi ban-all-sheds,

Thanks for quick reply! No I don't know much about testing the circuits, but I will be working with a friendly qualified spark who does. I'll be running my plans by him too before I start buying any parts, this is just the first sanity check to make sure I've not overlooked anything glaring...

Cheers
Richard

rcsdiy said:

Fridge & Freezer
Dedicated radial supplying both appliances in 2.5mm t&e from 16A RCBO via 13A fcu above worktop level
Unsure from research whether f/f on rcd is a good idea, but due to concealed wiring to fcu I don't have much choice unless I start burying steel pipe in the walls.

Click to expand...

Are you going to hard-wire those appliances - and, if so, why? If you simply plugged them into sockets, you wouldn't need an FCU, although you might decide that you want to have switch(es) for them above worktop level. As for the wisdom of having a freezer on an RCBO, I think people probably worry too much about that. If, as in your case, the RCBO is dedicated to just that one appliance, then the chances of a 'nuisance' trip is very low - and most situations which would cause 'genuine trips' would be those in which the freezer had, or was about to, stopped working already.

rcsdiy said:

Under cabinet lights
Haven't really thought about this yet, I think only option is to take a new run from existing lighting circuit? It'd be much easier to use the ring main but not sure this would be allowed?

Click to expand...

An FCU (say with a 3A fuse) off the ring would be acceptable. Probably quite a good idea, in fact, since it would mean you would still have some lighting of the main lighting circuit were to fail.

Kind Regards, John

Hi John,

Sorry, that bit wasn't very clear. I was going to use a single un-switched socket for each of the fridge and freezer. They're integrated appliances so the fcu above the worktop was really just to provide an accessible means of isolation. I realise now there's no need for the fuse, so i could just use a switch there.

Taking you're point into account I could ommit the switch entirely - if I did this to isolate the appliance you'd have to either unplug it, switch it off at its (now switched) socket behind the appliance, or switch the rcbo for the circuit. Would that be deemed accessible means of isolation?

I agree with your comments on the freezer/rcd issue, wasn't sure if the stuff on the web was just scare mongering!

I like your justification for cabinet lights off ring main too, makes logical sense and will save me a lot of digging in walls.

Cheers
Richard

rcsdiy said:

Sorry, that bit wasn't very clear. I was going to use a single un-switched socket for each of the fridge and freezer. They're integrated appliances so the fcu above the worktop was really just to provide an accessible means of isolation. I realise now there's no need for the fuse, so i could just use a switch there. ... Taking you're point into account I could ommit the switch entirely - if I did this to isolate the appliance you'd have to either unplug it, switch it off at its (now switched) socket behind the appliance, or switch the rcbo for the circuit. Would that be deemed accessible means of isolation?

Click to expand...

There is some merit in a local switch, but there are millions of examples out there of appliances plugged into sockets behind them which are essentially inaccessible until one has pulled the appliance out. As you say, one can always use the RCBO. That will only give single-pole isolation, but that's probably enough for 'emergency' situations. The apliance could then be puleld out and unplugged, if necessary.

rcsdiy said:

I agree with your comments on the freezer/rcd issue, wasn't sure if the stuff on the web was just scare mongering!

Click to expand...

There obvioulsy is a thereoretical risk, but I think the degree of that risk is probably very much overplayed.

rcsdiy said:

I like your justification for cabinet lights off ring main too, makes logical sense and will save me a lot of digging in walls.

Click to expand...

It makes sense to me.

Kind Regards, John

Thanks for all your help John, plans are coming on well!

I don't know what the Scottish regulations are. Likely most of the English electricians will also be lacking the local knowledge also. But I would assume you will need some local authority approval?

I would be looking at Ali-tube for the fridge and freezer supply so that they do not require RCD protection so will not have a problem when you go on holiday.

I would assume the local electrician will need to satisfy the local authority and I would be more interested in what he has to say than any one on this forum.

rcsdiy said:

Electric oven & gas hob
2500W oven, so planning a 16A radial from CU to cooker outlet in 2.5mm t&e.

Under cabinet lights
Haven't really thought about this yet, I think only option is to take a new run from existing lighting circuit? It'd be much easier to use the ring main but not sure this would be allowed?

Click to expand...

You or a future resident might want an electric hob in future; the extra cost now of putting in a 32A circuit is minimal but could save a great deal of inconvenience later.

You can use a FCU off the socket ring for the under cabinet lights if you wish.

ericmark said:

I don't know what the Scottish regulations are. Likely most of the English electricians will also be lacking the local knowledge also. ...I would assume the local electrician will need to satisfy the local authority and I would be more interested in what he has to say than any one on this forum.

Click to expand...

I may be wrong, but my understanding was that 'the regulations' (in relation to electrical installations) were identical throughout the UK, essentially amounting to BS7671. What obviously does differ in Scotland is the requirement for, and (when required) mechanism of obtaining, 'approvals' for electrical work - something which has not been discussed in this thread. However, in terms of "the electrician satisfying the local authority", I believe that is achieved by reference to the very same set of 'regulations' (BS7671) which are familiar to electricians in England and Wales, even when we are talking about work in Scotland. Am I wrong?

Kind Regards, John