chasing cables/ sinking back boxes

I'd glue them in with something like this:

cheers John, I wont have the problem with most of the boxes as i've got

is there a minimum depth for the cables to be channled? and would this be from the finished surface (i.e can I count the plastering as part of the cable depth) I have 2" PVC channel to go on top of the chases

Assuming the cables are in the permitted zones, then they only need to be deep enough for the plasterer to get a 3 to 5 mm (1/8 to 1/4 inch) covering over the channel. Anything less often leads to cracking as the plaster dries out.

If the cables are outside the zones then they need to either be 50 mm (2 inches) below the surface, or mechanically protected.

John

Cheers John, by zones i take it horizontal or vetrical in line with the visible outlet If so then they are all in. Also what is the permissable distance I can put a socket near a sink in the kitchen?

See:

This is one of those questions to which there is no definitive answer. The usual answer is either 305 mm (12 inches) or where they won't get splashed.

John

Cheers for the link, all cable runs comply !! I was under the impression I could not fit a socket in a location where I could touch the sink and the socket at the same time, which prevents me putting one where I would like. It will be a metre away so not likley to get splashed :-)

another issue I have is that some of the cables for the sockets need to come down through a joist next to the wall, but the holes would fall less than the permissable 0.25-0.40 zones for drilling holes. Bloody regs are starting to grate !! the holes would only be big enough for

Thanks in advance

In most houses that would prevent putting any sockets in the kitchenette.

I don't quite understand where the joist is (parallel or across the wall) but remember at the top ty millimetres of wall is a permitted zone too, so you can do a little wiggle horizontally.

Owain

Hi the joist runs with the wall and is flush with it ( not at 90) and I need to run several runs of 2.5 down that wall as this will be the main kitchen wall and will have 4 dbl sockets on it. the only option I can see to stay in regs is to run the cables to that wall through a hole in the permissable drilling zones and into the

Is this a top floor/single storey? IOW, is the joist supporting any weight or is it in tension preventing a pitched roof from splaying?

Either way, if the joist is supported by the wall it's unlikely to deflect, and without deflection drilling a few holes shouldn't weaken it sufficiently for it to give way.

But IANAStructuralEngineer and I haven't seen your house.

Owain

On 19 Sep 2006 10:42:26 -0700 someone who may be "Staffbull" wrote this:-

You should only need to run two 2.5mm2 cables down the wall, one at the "start" of the run of sockets and one at the "end". Cable can run horizontally between the sockets.

Hi Owain, its the fist floor of a two storey extension. BCO coming today to give me guidance

in that wall as well, as its by far the "buisyest" wall reagds chasing sinking I thought I'd start on that first, the rest should then be "plain sailing"

On 20 Sep 2006 02:00:31 -0700 someone who may be "Staffbull" wrote this:-

Presumably not 2.5mm2. Do you need separate feeds because you are controlling them from a central point, or just one permanently live feed to local switches? If the former could you use three core and earth, or some combination of cables if you have lots of the lights?

Presumably more than 2.5mm2.

run off the same junction box as a twin flourescent and two FCU's