Chasing in kitchen

[Rusty10]

Hi

We are due to have a new kitchen installed into what was the existing dining room.

I have had two extra 2 gang sockets installed however, as it is one will be situated over where the cooker is now to be located (had re-arranged the plan!)

It is chased up about 100mm from where the end of the cooker will be (pic on right)

I would like to re chase (pic left) but I think this might be wrong as the conduit will remain behind the cooker and you cannot chase horizontally?

Is this correct?

What would be the professionals opinion? If I was to re chase what is best product to fill the therm' plasterboard that the old chase & socket has left? The therm' boards will be skimmed over by a plasterer btw

Will the gas range cooker need to be connected to electrics, and what is required to cable in an extractor hood? I am happy to do the cabling and get an electrician to come in to connect.

Hope this all makes sense?

 

[Rusty10]

Ooops pics now inc'

 

[Rusty10]

//www.diynot.com/network/Rusty10/albums/6022/24227

 

[ericmark]

The rules want some one looking at bare walls to be able to work out where the cables run. So down to Switch then across and down or down and across to cooker outlet is allowed but not diagonal.

However down and then across without a switch or plate to mark where the cable changes direction would not be permitted.

You may need to get this all done before food preparation areas are installed. Until food preparation areas are installed it is not a kitchen. Once installed it is a kitchen and will need notifying under Part P.

Gas hobs often have power for ignition. Even my sons solid fuel cooker needs power for water pump to stop boiler overheating.

However normally low power so supply from ring main is good enough.

 

[Rusty10]

Thanks ericmark, very helpful advice thank you.

So having the cable traced behind the cooker (100mm from edge) would be ok, asssume there is a gap between the cooker and wall, and will not have any heat issues?

I have now read somewhere that you cannot chase into foam backed plasterboard! Is this correct?

 

[ericmark]

Not a clue I was an industrial spark.

 

[ban-all-sheds]

There's nothing wrong with having the cable behind the cooker.

But you will not then be able to turn a right angle to go to the socket - you'd have to have the socket above the cooker, which of course you can't.

You have to completely re-route the cable so that it drops vertically down from the socket.

• http://www.voltimum.co.uk/files/gb/attachments/niu/l/attachments/c5-43.pdf
• http://web.archive.org/web/20061110111450/http://www.niceic.org.uk/downloads/concealedcables.pdf
• IEE article
• IEE Article on 17th Edition requirements for concealed cables.

You might be happy to do the cabling, but what if the electrician you get in is not happy with what you've done?

Is the circuit RCD protected?

Are you aware that it's not just connection that's required, it's testing as well? And that you'll not get an Electrical Installation Certificate?

What stage are you at in the change of this room - is it already technically a kitchen?


As for the plasterboard, it depends.

1) You may not increase the u-value of the insulation too much.

2) You may not perforate the vapour control layer.

3) You must allow for the effect of the insulation on the current carrying capacity of cables when choosing the size.

 

[Rusty10]

Many thanks for the feedback!

The socket was already connected, and I will move it to the left and re-chase vertically.

The circuit is indeed RCD protected.

All will be connected and tested by electrician.

The room, is still a shell and by no means technically a kitchen

The cables have been installed previously by the electrician, so I presume he has got the correct capacity & size - I am just moving them to the left?

Plasterboard will be chased right back through to the wall so all 'foam' and board will be taken off, will this effect u-value & vapour control (am unsure of a what a vapour control layer is??)

It will be covered by oval conduit

Thanks again

 

[ban-all-sheds]

Cutting away a strip of the board like that will increase the u-value at that point and create a cold bridge. Check with Building Control - I suspect that might contravene the Building Regulations.

The vapour control layer will be on the warm side of the insulation. Its purpose is to prevent water vapour getting through to the cold side, because there it will condense (e.g. on the cold brick wall), and start growing mould, causing rot etc. You'll find (I hope) that the composite board has a layer of foil on the back of the plasterboard, i.e. on the room side of the insulation.

Check on the Building Forum - I'm pretty sure there are sealing tapes etc that you can use to re-seal any breaches.

 

[mointainwalker]

Whether or not there is foill on the bonded pb is irrelevant. Polystyrene is completely impervious to water-vapour so cutting into the poly is not a problem as long as you don't go too deep as you still risk condensation when the insulation is too thin .

 

[ban-all-sheds]

1) It might not be polystyrene.

2)

Plasterboard will be chased right back through to the wall so all 'foam' and board will be taken off

 

[mointainwalker]

Polystyrene ( extruded/expanded), PIR, polyurethane - believe that covers it - all have the same charcacteristic- impervious to water.

Re quote

He'd better make it a very thin chase then ( or is that regulated ?)

Edit":Filling chase with expanding foam should cover any probs with the U-value and permeability

 

[Taylortwocities]

If it is polystyrene, be sure that it is not in contact with PVC cables..

Read all about it

http://www.generalcable.com.au/Technical/10.1.1.1.pdf


I picked up that in NZ they have a "polystyrene friendly" type of cable. It is purple in colour.

Also PVC cables are OK in contact with polyurethane or polyisocyanurate. The polymers are different and do not have residual chemicals present that are found in polystyrene.

There, education complete!

 

[ban-all-sheds]

So why, if you put a piece of PIR or PUR into water (weighed down) does it absorb some?

Unlike EPS.

And why do some insulation boards, plain and composite, have a VCL - is it all some vast con on the part of Celotex, Kingspan, Knauf etc?

 

[mointainwalker]

I'm not aware that it/they do ( ignoring the tiny amount of cut/fractured cells around the edge.)

These are closed-cell foams and rely on holding the gassing agent within the cells for their insulating properties and if water vapour could migrate through the structure then the insulating gas would be able to do the same and bingo - poorer insulation.

My belief is that the foil applied to the boards is simply marketing , to attempt to blunt the sales of multi-foils by showing/confusing the unknowing punter with a "similar" shiny surface. Have not seen any explanation for this in their literature.