How deep can you channel in to breeze block - TV cables

[Adam75]

Hi

I wish to hang my plasma on the wall & hide all the cables:

3 x hdmi
1 x coaxial
1 x Ethernet
1 x power

Ideally I'd like to channel each cable in a big enough channel so they can removed or changed without replastering.

Instead of doing individual channels for each cable in trunking I was wondering if I could do 2 channels, 1 for the power & the other for all the 5 other cables. Assume I should keep the power separate from the others to avoid electrical interference.

The channels will need to be about 1 meter long.

The wall is an external brick wall with an insulated cavivity and plastered breeze block.

Has anyone done something similar or know how deep you can cut in to breeze block without causing structural issues?

Thanks
Adam

 

[DetlefSchmitz]

Vertically 1/3th of the wall thickness, horizontally 1/6th.

Power needs to be separate for insulation rating reasons according to regs.

 

[Adam75]

Thanks, is that 1/3 of the total wall or just the depth of the breeze blocks?

 

[EFLImpudence]

Thanks, is that 1/3 of the total wall or just the depth of the breeze blocks?

The block. Don't count the plaster.

 

[DetlefSchmitz]

The breeze blocks. There is always some disagreement on the next bit, but if this was an unplastered wall you could go in 1/3, so probably 33mm.

If the wall is plastered that implies you can go through the plaster and then another 33mm.

Some people will say the plaster is part of the wall, but that is not really logical.

 

[Adam75]

I suppose the other obvious question, is there a limit to how many individual channels you can have, say 16mm deep?

 

[EFLImpudence]

No.

 

[EFLImpudence]

Some people will say the plaster is part of the wall, but that is not really logical.

The regulations say one third of the leaf which is not the plaster.

 

[riveralt]

Ideally I'd like to channel each cable in a big enough channel so they can removed or changed without replastering.

One option is to channel out the plaster and breezeblock then put plasterboard over the channel(s) thus creating a void and finally skim the plasterboard.
This might work for one cable but if you intend to put 5 cables in one channel you may not be able to pull them through and some types of breeze block have quite sharp bits which could snag and/or damage the cables.
If you opt to utilise plastic channels and bury them in the wall you may still run into some of the problems outlined above. However, cables have a nasty habit of snagging and with hdmi you are going to need at least 25mm ² channels

The simplest option is to channel out the plaster back to the breeze block and then plaster in the new cables. I think you need to ask yourself how many times are you likely to have to change the cable set up - looks to me that you already have more than enough cables to cover most eventualities.

 

[DetlefSchmitz]

I guess the answer is that there is no such limit in the building regulations. I think common sense has to prevail though.

Maybe someone else knows better here?

 

[PrenticeBoyofDerry]

I suppose the other obvious question, is there a limit to how many individual channels you can have, say 16mm deep?

There is no limit, other than you can not have back to back chases and chases positioned in a manner that would impair the stability of the wall.
Also extra care should be taken, if the walls constructions is that of hollow bricks!

 

[SimonH2]

I would suggest plain "white oval" conduit for power, and put some plastic rectangular trunking in for the data/AV. You should be able to get a 25x40 trunking in and still get a decent plaster cover over it. That's more than enough to get things like HDMI through.
Actually for the list you've given, I reckon 16x25 should do.

The plastic trunking gives a nice smooth internal surface - nothing for the connectors to snag on as you try to thread them through.