Conservatory Cavity Wall Query

[shaggie16]

Hoping someone can help.
New conservatory being built, with 450mm dwarf cavity wall, brick outer, thermalite inner, no cavity insulation.
I need to have power and lighting cables run, and my initial thouhts were in capping on the thermalite which would then be covered by dot and dab plasterboard.
I am told not allowed to do that, (something to do with horizontal runs of cable x mm from the floor) and have been told they should be run in the cavity. Well, OK, that's no bother and will use conduit to do so.

Now, rightly or wrongly, I want (purely for effect) some dimmable low voltage halogen "guide lights" set recessed in to the wall on the inside - These in fact:

20W G4 LV Reflector|Recessed Wall Lights

My problem is this. They are 20W G4 lams, and there will be 8 of them on a dimmer. My initial plan was to have one transformer and run the lot off that, but the low voltage cable run would be way too long I think and the voltage drop would be hideous.

How can I get around it? Multiple transformers, yes, but being a cavity wall, there won't be space anywhere to put the extra transformers, so where can I put them? They are small items, but obviously in the cavity secured to the thermalite is a no no because of damp. I don't really want to lose 2cm of space behind the plasterboard, plus that would be a nightmare if (sorry when) one of the transformers failed.

SO, any ideas how I can achieve this?
I have looked for other ways of doing it, ie LED fittings, mains voltage halogen fittings, but the requirements are a shallow recess as these are going into a cavity wall, and they must be dimmable. Most LED guide lights I have seen of similar design are cold white and are NOT dimmable.

Please help!

Thanks in advance

 

[shagbite]

employ an electrician who knows how to design a lighting circuit.

 

[telectrix]

you can run cables horizontally between sockets under the plasterboard. fit the transformers behind the lights.

 

[shaggie16]

Whilst I have every intention of using an electrician, I always want to avail myself of possibilities. My experience of any trade, be it electricians, plumbers, even my own, whoever you speak to will often recommend solutions they are themselves familiar with. That in itself is of course good practice, but it doesn't neccessarily give me the widest choice.

So, whilst I am looking at what is available and how I can use it, I ask the question above.

 

[shaggie16]

Telectrix - thanks for your reply. My only concern here is that the lights are deeper than the dot and dab, so will require a little notching out of the thermalite to fit them. How can I fit the transformer behind the light if that is the setup?

 

[kingeri]

You can't change the laws of physics, you'd need them to physically fit, if you're on about those thermalite bricks then you can notch into them if required but it's not ideal on a new build.

 

[shagbite]

Whilst I have every intention of using an electrician, I always want to avail myself of possibilities. My experience of any trade, be it electricians, plumbers, even my own, whoever you speak to will often recommend solutions they are themselves familiar with. That in itself is of course good practice, but it doesn't neccessarily give me the widest choice.

So, whilst I am looking at what is available and how I can use it, I ask the question above.

well, forgive me, but when someone comes on here, asking how they can 'get around volt drop', my spidey sense starts tingling and i reckon they're gonna have a crack at it themselves.

 

[shaggie16]

well, forgive me, but when someone comes on here, asking how they can 'get around volt drop', my spidey sense starts tingling and i reckon they're gonna have a crack at it themselves.

I see. I do know how to get around voltage drop, I have a degree in physics, but I don't want to use 6mm cable, and what I was struggling with was whether I would simply need to rethink what I actually want to achieve because although multiple transformers placed nearer the lights will also combat the problem, I am unsure on whether it is possible to either hide the transformers somewhere, or just change tack and look for LED fittings. However, as stated, I cannot find any LED fittings that are warm white and shallow recess.

To be fair, I didn't ask how I can get around voltage drop. I identified it as a problem, and asked how I could place the transformers, or if there were alternative but similar fittings such as LED that people were aware of, that are warm white and shallow recess.

 

[telectrix]

the lights ask for 45mm depth. i'd cut right through the thermalite, thats 100mm, so loads of space for transformers.and LED lights are a good option.

 

[shagbite]

I see. I do know how to get around voltage drop, I have a degree in physics, but I don't want to use 6mm cable, and what I was struggling with was whether I would simply need to rethink what I actually want to achieve because although multiple transformers placed nearer the lights will also combat the problem, I am unsure on whether it is possible to either hide the transformers somewhere, or just change tack and look for LED fittings. However, as stated, I cannot find any LED fittings that are warm white and shallow recess.

To be fair, I didn't ask how I can get around voltage drop. I identified it as a problem, and

asked how I could place the transformers,

or if there were alternative but similar fittings such as LED that people were aware of, that are warm white and shallow recess.

i'm afraid my answer remains the same. you should find an electrician who has the knowledge and ability to carry out this installation satisfactorily.

 

[shaggie16]

Telectrix - so just so I am clear in my own mind with regards to seeing what products I can use - I can get the electrician to cut right through the thermalite into the cavity, and put the transformer there? That won't affect the strength of the wall or indeed the waterproofing? The transformer would be ok sat in the cavity like that?

If that's the case, is it also possible to mount the transformers in the cavity itself just under the windowboard? If one failed, I could easily remove the window board to have it replaced. I just assumed the cavity would get too damp to do that?

Once again I should point out that I am not planning on doing this myself, I simply want to know what products I can use so I can get the best choice.

 

[HandySparks]

However, as stated, I cannot find any LED fittings that are warm white and shallow recess.

Why not just fit G4 LED lamps to the fittings you've found. They're certainly available in warm white. Not sure about dimmable, you may have to experiment with some samples.

 

[tom79bmth]

Hiya will the transformers fit in a metal knock out box and put a blank on the front so you can access them

 

[shagbite]

that'd look pretty rough, to be honest mate.

 

[Engineer54]

If these fittings have already been purchased, then try and get them replaced at the store they were purchased from, as clearly they are not suitable for this installation. Replace them for full voltage fittings of whatever lamp type is available.

As the old saying goes, you can't fit a square peg into a round hole. You will always end-up with a real pig's ear of a job!!!

 

[telectrix]

but , the again, he's working with a dwarf wall in a conservatory. not like it's holding up much weight. nothing wrong with cutting right through the thermalite.

 

[Engineer54]

but , the again, he's working with a dwarf wall in a conservatory. not like it's holding up much weight. nothing wrong with cutting right through the thermalite.

Wouldn't that be destroying the integrity of having a cavity wall, ...there are after all 8 of them i believe?? I certainly wouldn't want to install TX's in the cavity. Far better to have a fitting that is suitable for it's location....

 

[shaggie16]

Thanks for the ideas. Nothing has been bought yet - I am not doing this job myself. I'm purely trying to get ideas of what will and won't work, so I can make sure that when I sit down with the electrician, I know all ideas have been thought about.

So, LED bulbs - good idea. Cutting through the thermalite could also work.

With regards to the mains voltage fittings, my concern here is recess depth. But are we saying then, that I shouldn't limit my thoughts to shallow recess because of the wall contruction, as cutting deeper into the thermalite isn't an issue? If the fitting is IP rated would it matter if it went all the way through the thermalite into the cavity?

A greater allowable depth would certainly open the world of opportunity with regards to which fittings would work.

 

[Engineer54]

Thanks for the ideas. Nothing has been bought yet - I am not doing this job myself. I'm purely trying to get ideas of what will and won't work, so I can make sure that when I sit down with the electrician, I know all ideas have been thought about.

So, LED bulbs - good idea. Cutting through the thermalite could also work.

With regards to the mains voltage fittings, my concern here is recess depth. But are we saying then, that I shouldn't limit my thoughts to shallow recess because of the wall contruction, as cutting deeper into the thermalite isn't an issue? If the fitting is IP rated would it matter if it went all the way through the thermalite into the cavity?

A greater allowable depth would certainly open the world of opportunity with regards to which fittings would work.

Don't be bloody stupid!! Why do you want light fittings on such low walls anyway, why not wall lights at a suitable height on the existing wall the conservatory is attached too?? If you're dead set on having these low mounted lights, purchase suitable full voltage fittings rather than LV ones that require a TX, or fittings that incorporate an integral TX!!

 

[shaggie16]

I did say in my initial post that I assumed things cannot go into the cavity! So the question remains then. Whatever fitting is used in these low level lights, will, at least in part, need to be notched out of thermalite block behind the dot and dab plasterboard. So WHAT DEPTH is permissable to notch out of the block to incorporate the recessed fittings?

 

[shagbite]

in general, conservatories are exempt from building regulations, as long as they abide by certain criteria, e.g. they are built at ground level & have a total floor area of less than 30m2. it would be up to you and your builder to determine which category your project falls into.

as a guide, the building reg's don't allow block work chases of more than 1/3 of the thickness of the block for vertical chases, and 1/6 of the thickness of the block for horizontal chases.

 

[cossie400]

I wouldn't be happy fitting anything in a cavity without the correct IP rating as it will be subjected to condensation etc.

Is there a sill running around the top of the wall that overhangs at all? If so what about some of those LED tape strips that you can cut to length? Like this...
LED Strip Lights & LED Tape Lights

And fitted to the underside, would also allow you to fit the transformer in a suitable location.....

 

[mayfair]

Shagbite. Not what this forum is for the OP asked a civil question. If you cant say something helpful i suggest you shut up Tho i see your been a bit more helpful later on.

 

[shagbite]

Shagbite. Not what this forum is for the OP asked a civil question. If you cant say something helpful i suggest you shut up Tho i see your been a bit more helpful later on.

chupar mi ciruelas.

if you don't like it, stick it where the sol don't shine.

 

[i=p/u]

You could build a stud wall 2x2 putting wee nogin below light to sit transformer on.

But I would try look for 230v light or change your shell to suit

 

[robsparky1975]

Exactly as above,if you are that intent on fitting recessed lights,stud off of the thermalite to allow sufficent room for lights and adjust the sill to suit aswell.

 

[shaggie16]

I wouldn't be happy fitting anything in a cavity without the correct IP rating as it will be subjected to condensation etc.

Is there a sill running around the top of the wall that overhangs at all? If so what about some of those LED tape strips that you can cut to length? Like this...
LED Strip Lights & LED Tape Lights

And fitted to the underside, would also allow you to fit the transformer in a suitable location.....

I was going for the LED tape as well, been a fan of the stuff for years, as well as central lighting. It won't all be on at the same time of course, just have always gone for plenty of mood lighting around the house. The whole lot will be controlled by Wise wireless controls, including the RGB output of the tape.

That was my concern with the cavity too. So shallow fittings remain necessary then.

 

[shaggie16]

Thanks for the studding idea, that def would allow me the fittings I have in mind.

 

[robsparky1975]

You can buy led striplight that changes colour AND is dimmable via the remote control they supply and i have fitted some in a kitchen and its pretty good and suprisingly bright.

 

[shaggie16]

You can buy led striplight that changes colour AND is dimmable via the remote control they supply and i have fitted some in a kitchen and its pretty good and suprisingly bright.

Yep, have some elsewhere. I'm going for the Wise controls though for two reasons. First I want to control all 4 channels of lighting that will be in the conservatory from one switch, and second, I want to be able to control the colour and brightness of the LED strip from the same switch. Wise is the only company I have seen that will allow this, using one of their Chameleon scene packs.

 

[Engineer54]

From what i can see here , you're not going to listen to any advice if it doesn't fit in with what you want to do, but can't!! As i said earlier you can't fit a square peg into a round hole, so unless you get suitable fittings with or without TX's it ain't gonna go your way, end of!!

 

[shaggie16]

From what i can see here , you're not going to listen to any advice if it doesn't fit in with what you want to do, but can't!! As i said earlier you can't fit a square peg into a round hole, so unless you get suitable fittings with or without TX's it ain't gonna go your way, end of!!

I'm unsure as to how you arrive at that conclusion. It has been mentioned, including by you, that going through the thermalite into the cavity is a bad idea. I have stated in a previous post "shallow fittings remain a necessity then", clearly heeding this advice. I have also thanked people who have offered advice that would make this setup work, such as using LED bulbs or studding out the wall to make space for the fittings. All are good ideas and would solve the problem.

I do admit, what I haven't listened to are comments such as "why do you want those lights anyway." Because I do, and if it's possible to have what I would like, of which a few methods have been suggested above, then that advice has been listened to and people thanked for it.

 

[SPARTYKUS]

Hi

just a note re: your windowboard idea, I think thats a non-starter as if its been built correctly, there won't be access to the cavity under the windowboard... Its usually (!) lined. Can't remember the name of the stuff but its plastic with polystyrene in it.

Having read through the whole thread I feel your best option is not to use transformers. No need. Another thing to go wrong.

cheers.

 

[mayfair]

Members of the General public ie posible customers visit these forums we need to show a professional atitude towards all questions asked and try to help where possible. Wonder why the trade is going downhill in the UK ????

chupar mi ciruelas.

if you don't like it, stick it where the sol don't shine.

 

[shagbite]

Members of the General public ie posible customers visit these forums we need to show a professional atitude towards all questions asked and try to help where possible. Wonder why the trade is going downhill in the UK ????

read my first three posts again, then come back and tell me what's unprofessional about telling someone to employ a competent electrician to carry out an installation.


when someone tells me to shut up, i respond accordingly. if you are unhappy with this kind of response then you shouldn't provoke people.

 

[Paul505]

that'd look pretty rough, to be honest mate.

That made me laugh.. you dont beat around the bush ;-)