12V Wiring inside cavity wall

[Dangermike]

Ok so a lot of research has go me to a question.

I want to add 2 wall lights in my Kitchen above the sink and window.

its a textured external cavity wall, so channeling is not ideal,
its a textured ceiling to channeling that is not ideal either,

Regulations state i cant use the wall cavity to hide my cables...

so i was stuck,

until i thought of using 12v lights!.
i have a suitable location for the transformer,
i just need to know if i can run 12v cables in the cavity?
The cavity wall in insulated.

Do they have to follow the same regulations as 240v?

 

[jj4091]

https://download.hager.com/hagergro...uct_Information/low_lighting_requirements.pdf

 

[Dangermike]

Thanks, that was a good read,
Couldn’t see any where mentioning external cavity walls... but maybe I’m not reading between the lines

 

[ericmark]

Electrically 230 volt would be better than 12 volt as lower current so less heat.
I think the idea behind not running cables in a cavity wall is heat, as cavity filled with insulation so it can't get rid of the heat, the BS7671 regulations are not law, so you need to do a risk assessment and decide if using the cavity is too great of a risk, much will depend on how the cables are run, with foam blocks with cables pushed hard against the brick then unlikely to over heat, with beads and the cables is centre of the two brick walls, then a lot higher chance of over heating.

The regulations do point out where the cable is makes a big difference, may sound daft, but experience has shown me cables bunched tend to fair better, as rarely are they run at maximum power so a cable with no power helps cool a cable with overload, many times I have found a burnt out cable, which in some parts was in a harness with others, and on opening the harness have found it has survived in the harness, only in free air has it been damaged.

When I have been faced with the problem I have used exterior cable and run it up or along the wall outside then brought it in again, including getting a friend who was use to working with mineral insulated cable to do the potting and you hardly notice the cable is there.

I remember trying to change a consumer unit for my sister, it seems the little balls should have a glue added, but this was missed, so the insulation just started to pour out of the wall, so few small holes drilled and expanding foam added and allowed to set first, even before it was frowned on to run cables through the cavity I would never try to run them after the building was finished, trying to thread cables through a cavity is near impossible. In the main used trunking with some spare cable so next time decorated can be let in the wall, or use flex and follow skirting around sticking it in place with silicon sealant, OK fire regulations no longer allow that, officially anyway, but some times you need to forget regulations and use common sense.

 

[securespark]

SELV cables can be sited outside safe zones.