Chasing for data cable - conduit?

[SimonH2]

You don't need to put a separate box next to the existing box as you can get 2&1 backboxes

Dual 35mm KO Flush Box (1 x Single + 1 x Twin) | Green (GSK335D / DB3512)

andhaving the faceplates tight against each other looks much neater in my opinion

Not seen those, nice.
Only trouble is it's fiddly plastering across the bridge. If you don't, then fittings can bend or crack (depending on materials) due to lack of support on one side. And/or you have loose fittings.

Yep, I've used those already in another post suggested by Murdochcat. I cannot find them with 25mm depth, so If I use 35mm I need to actually chase into the brickwork. I will think about it as it will indeed be much cleaner than just slapped somewhere above.

while it's a bit more work to go 35mm, the extra space in the box is well worth it.

 

[Sureitsoff?]

you are right about the "bridge " being awkward to plaster, the dry lining boxes are better in that the bridge is level with the rest of the rim

Appleby Dry Lining Boxes

Need to fit a double and single socket into a plasterboard wall? This 2+1 gang dry lining box is so easy to work with – it comes with two side cable entry points and a 25mm base knockout, along with adjustable lugs for a simple installation.The lugs have large bearing faces for superior...

www.toolstation.com

 

[nero44]

mhmm so I went with the chimney void Idea, but it did not quite work out exactly. This portion of the building only has two floors, so in theory the chimney construction should something like this.

Via the loft, I drilled a 45deg downward sloping hole (to avoid a strong cable bend) and fed the cat cable down. I definitely have drilled into a void, but the cable is not coming down despite feeding 2m into the hole. I thought I had gotten the wrong flue, the one feeding the other floor, so I drilled another hole on the others side of the stack. Same issue.

Could it be some damper stopping my cable from dropping down into the actual fire place? Any other ideasI could try? I only have limited access from either side. The loft only has that 10mm hole I drilled and since the chimney is boarded up, I am navigating through that one hole from the double socket.

 

[Why Not Indeed]

USB endoscope camera on a 3m cable can be had for not much at all. Was useful when fishing cat6 down a wall cavity.

 

[Harry Bloomfield]

USB endoscope camera on a 3m cable can be had for not much at all. Was useful when fishing cat6 down a wall cavity.

Yep, or a lump of lead/ fishing weight, on the end of piece of line.

 

[SUNRAY]

mhmm so I went with the chimney void Idea, but it did not quite work out exactly. This portion of the building only has two floors, so in theory the chimney construction should something like this.

Via the loft, I drilled a 45deg downward sloping hole (to avoid a strong cable bend) and fed the cat cable down. I definitely have drilled into a void, but the cable is not coming down despite feeding 2m into the hole. I thought I had gotten the wrong flue, the one feeding the other floor, so I drilled another hole on the others side of the stack. Same issue.

Could it be some damper stopping my cable from dropping down into the actual fire place? Any other ideasI could try? I only have limited access from either side. The loft only has that 10mm hole I drilled and since the chimney is boarded up, I am navigating through that one hole from the double socket.

I drop a length of chain ~6-12 inches long on the end of a piece of string and mark the string say every yard. Sometimes I use a tube in the drilled hole to get the drop into the centre of the void to clear any obstructions (such as mortar bulges)