Chasing walls for PVC conduit

[Nozzle]

I'm planning to use some of this
https://www.tlc-direct.co.uk/Main_Index/Trunking_Pvc_Index/Maxi_42_Univolt/index.html with some internal corners to go around a chimney breast. TV mounted on the chimney breast, Satelite, PS3, Blue ray etc sat on an adjacent shelf out the way around the corner - perhaps 3 or 4 feet away. I was going to use brush plates on either end of the conduit, and have separate routes for mains cables and low voltage cables, HDMI, COAX etc.

I've stuck this in the electricals forum rather than A/V as my questions is more about the conduit installation as anything else.

So this conduit is 2 inches deep, and I plan to chase it into the plaster/brick rather than surface mount it. How deep really should the chase be as I'm concerned it might just take the strength of the chimney out if there's a 50mm horizontal gash around it... I suppose I could semi-recess it then get some dot+dab done to take up the rest of the depth.

What's the common practice with deep trunking?

Nozzle

 

[Iggifer]

The common practice is to not sink dado trunking into the wall! Totally not what it's designed to do and tbh, won't work very well.

When you say around you mean at floor level horizontally? If you can describe a little better the plan, we can probably come up with a better solution.

You're allowed to chase 1/3 of the leaf or wall depending on structure. Your fireplace is likely to be a double layer of brick, so a reasonable amount of depth but still not a good plan.

 

[Iggifer]

I'm assuming the fireplace is bricked up?

 

[Nozzle]

The cabling is to be at waist height, there is a wood burning stove on the floor which vents through a register plate and liner. There is a fairly nasty mantle piece that is iron with stone mortared on to it... (which give me an idea, I could replace the mantlepiece with something hollow to run trunking through).

I hear what you're saying that this stuff isn't supposed to be burried - is there any way I can use the brush face plates:

and have them surface mounted rather than on the non-surface mounted dado trunking!

Nozzle

 

[flameport]

What's the common practice with deep trunking?

Not to use it.
For cables to a TV, two or possibly three pieces of 38x25mm trunking is plenty. 25mm being the depth.

You do not want any corners, internal or external, as this will make it next to impossible to draw cables in afterwards.

 

[Iggifer]

If you're going to have corners, you may as well chop boxes in and cap the cables to the wall, because as flameport says, you'll never pull anything through it if you've got bends.

 

[EFLImpudence]

You may not be able to go two inches deep.

The maximum allowed by Building regulations for horizontal chases is one sixth the thickness of the leaf, so if a four inch brick - 17mm - plus the plaster.

 

[Iggifer]

EFLI is right of course, 1/3 is for vertical chases. So you can maybe get some 25x38 trunking in with wet plaster, more if you dot and dab the wall out - which would look awful with an existing fireplace

 

[Nozzle]

The existing fireplace looks pretty bad anyway! Thanks for the advice and reference to the rules and regs. I now firmly know I cannot do any burried trunking on the scale I had planned. I'll have to carefully stuff some HDMI/USB/Co-ax/T&E into a number of smaller lengths of trunking - and know I'll never be able to pull new leads through, or I might get a fireplace that's a bit more modern and route a large slot in the back and trace cable through that. I think the T&E should probably take a different route, to be a more conventional installation and to keep them separated from the signal cables.

Nozzle

 

[Taylortwocities]

The problem with VA cables and trunking is that, for most cables, they come with the connector (HDMI, etc) on each end. So there is always an issue.
You might be able to uses something like this https://www.tlc-direct.co.uk/Products/MTMIN3.html
and plaster over.

But it will only be good for a few years before HDMI is replaced with something else. USB-C is already out there and coming to devices that you will be buying soon!

 

[Iggifer]

You can do HDMI over CAT6 but obviously requires somewhat clunky converters at either end, and a standard HDMI lead is much cheaper.

If the cable run was just a straight vertical, then there's lots of ways to do it, but going around a fireplace is not ideal.

 

[Nozzle]

iggifer: What are the options for straight vertical?

TaylorTC: As you say the end connections are the problem, some even have large chokes crimped over the end. Which I why I thought having a broad trucking with brush plates would solve this particular problem.. At least I don't have ghastly SCART to deal with..

Nozzle

 

[winston1]

iggifer: What are the options for straight vertical?

TaylorTC: As you say the end connections are the problem, some even have large chokes crimped over the end. Which I why I thought having a broad trucking with brush plates would solve this particular problem.. At least I don't have ghastly SCART to deal with..

Nozzle

Ghastly Scart as you call it is rewireable so you can fit the cables then the plugs, but sadly that is now history.

 

[Tigercubrider]

I assume that you don't have suspended floors?
Or go up- across- down from the room above?

My inclination would be to go under if possible.
You can get "fake" skirting board that is hollow in place of trunking

I have been guilty of the "future proofing" thing before and invested time and effort installing never used cables that are hidden and end up never being used

In my day job I helped plan a theatre and film complex and we had to change the cable types twice during planning as different cable standards came and went. Bear in mind that there is a max run for HDMI

 

[plugwash]

For HDMI one option is to use cables with micro connectors and then use adaptors to connect them to the equipment.