Where to route the wires

[MortarThePoint]

Happy new year everyone! I'm deliberating on where to route my services and most significantly the wiring. Water is concentrated at two ends of the house, so I can do all that routing vertically and via the roof space. Electrical wiring on the other hand needs to go to all rooms. I am considering a very bold move of having almost no wired in light switches and using home automation for almost all lights in conjunction with wireless light switches. The reason I mention that is that it saves routing wires down from ceiling lights to switches and therefore makes the majority of the consideration around sockets.

 

We have precast concrete ground and and first floors, so I see the following main options for routing the mains for sockets:

1. False ceiling, would have to chase down to the sockets
2. Conduit buried in floor screed, would have to chase up to the sockets
3. Chased into wall horizontally and vertically
4. Within skirting boards, would have to have screed conduit for doorways

 

Avoiding a false ceiling has a load of benefits. The architect has included false ceilings, but I'd like to rethink that.

[willbish]

Where's the MVHR ducting going? I thought that would require the false ceiling. Then you've got the voids for the cables.

 

What's your plan for wall finish on the precast concrete? A service cavity could be easier than chasing. 

[Olf]

11 minutes ago, MortarThePoint said:

I am considering a very bold move of having almost no wired in light switches and using home automation for almost all lights in conjunction with wireless light switches

I think nowadays bold move would be to rip the walls for the sake of a physical switch! I had stairs 2 way switch placed 'conveniently' (for the electrician for sure, made no sense to me), moving it would take me a day of chasing/redecorating. I spent maybe 1/2 hour to install 2 wireless PIR sensors and set them up. Added bonus: light intensity set depending on the time of the day, so when doing fridge run at midnight neither I'm blinded by the stairs light, nor alarm/wake up everyone.

 

12 minutes ago, MortarThePoint said:

Within skirting boards, would have to have screed conduit for doorways

Obviously that one is the least laborious, especially when you choose 'posh' tall skirting boards and can live with protruding boxes, you may end up with no chasing at all!

But tall skirting is a must in this case: I now have standard (~100mm) and I don't like bending so low to plug anything and most of the cables coming off the plugs seem to be forced against the floor.

[Declan52]

Precast concrete slabs aren't exactly level underneath so it's easier it batten it out and use plasterboard. The space from the battens give you room to run all your cables.

On the first floor the cables are run in conduit and then buried in insulation or the screed.

Chasing the walls is an easy job now with a wall chaser. 

[MortarThePoint]

2 hours ago, willbish said:

Where's the MVHR ducting going? I thought that would require the false ceiling. Then you've got the voids for the cables.

 

What's your plan for wall finish on the precast concrete? A service cavity could be easier than chasing. 

 

We're not having MVHR so no ducts to worry about there. Wet plaster seems to be OK on the precast:

    

 

[MortarThePoint]

2 hours ago, Declan52 said:

Precast concrete slabs aren't exactly level underneath so it's easier it batten it out and use plasterboard. The space from the battens give you room to run all your cables.

On the first floor the cables are run in conduit and then buried in insulation or the screed.

Chasing the walls is an easy job now with a wall chaser. 

 

We're not using insulation in the first floor make up. The screed will probably be thick enough to bury a reasonably sized conduit. As a moderate commitment-phobe, I'm not so keen on the finality of burying things though.

[ProDave]

What is your WALL construction?

 

No you CANNOT run cables behind skirting board.  Look up "safe zones" which basically says cables can only be buried in walls horizontally or vertically from a switch or socket, and you can't have your sockets at skirting board height, Building regs set the minimum height of a socket.

[Gone West]

6 minutes ago, ProDave said:

Look up "safe zones" which basically says cables can only be buried in walls horizontally or vertically from a switch or socket

Or horizontally at the top of a wall within 150mm of the ceiling. I think this is current (pun).

 

Edited January 6, 2021 by PeterStarck

[Bitpipe]

4 hours ago, MortarThePoint said:

 I am considering a very bold move of having almost no wired in light switches and using home automation for almost all lights in conjunction with wireless light switches.

 

The joy of self building is you can spec what you like but always worth thinking about what that choice may look like in 10 years, especially if you want/have to sell on. Or plan for contingency for equipment failure, redundancy etc.

 

In the grand scheme of things, ducting and cabling is relatively inexpensive to put in during first fix and very disruptive to do so later. Many of us here have had our bacon saved by a spare duct or two that was put in 'just in case'.

 

If you don't make provision for wired light control and later realise that wireless only was not a great choice (or your wifi network has an issue), then you're stuck. If you do put in provision for wired control and decide not to use it, you can conceal and it's always there if you (or someone else) chooses to use later.

 

A networking rule of thumb is to use wired connectivity for things that don't move and wireless for things that do. That may be a bit old hat now but I have cat 6 everywhere and use a surprising amount of it for TVs, gaming boxes etc..

[ProDave]

May favourite scheme is have at least one socket on each wall of a room, and run the socket cables around the room horizontally at socket height.  Then you can add further sockets anywhere you want to in the room easily when the need arises.

[TonyT]

I spoke to my local authority about sockets and switch positions asking them that I would like them to match the existing house, sockets in skirtings and light switches slightly higher.

they were fine about it, email kept for evidence.

[Big Jimbo]

4 minutes ago, ProDave said:

May favourite scheme is have at least one socket on each wall of a room, and run the socket cables around the room horizontally at socket height.  Then you can add further sockets anywhere you want to in the room easily when the need arises.

Im with ProDave above. Atleast One socket on each wall. Each room on a radial circuit, and slack inbetween. Anytime you want an extra socket, cut ahole and cable is there waiting for you.

[MortarThePoint]

2 hours ago, ProDave said:

What is your WALL construction?

 

No you CANNOT run cables behind skirting board.  Look up "safe zones" which basically says cables can only be buried in walls horizontally or vertically from a switch or socket, and you can't have your sockets at skirting board height, Building regs set the minimum height of a socket.

 

The walls are mostly 100mm blockwork. I will take a look, but I think Part A limits chasing to "Vertically not deeper than one third of the thickness, horizontally not more than one sixth the thickness of the wall" [1] That's plenty mind you for plastered in wires.

 

2 hours ago, PeterStarck said:

Or horizontally at the top of a wall within 150mm of the ceiling. I think this is current (pun).

 

Thanks for this. I think (??) you can use conductive conduit outside these safe zones and as such could have it in skirting board if the skirting board was deep enough to enclose conduit, or was itself conduit.

[MortarThePoint]

2 hours ago, Bitpipe said:

 

The joy of self building is you can spec what you like but always worth thinking about what that choice may look like in 10 years, especially if you want/have to sell on. Or plan for contingency for equipment failure, redundancy etc.

 

In the grand scheme of things, ducting and cabling is relatively inexpensive to put in during first fix and very disruptive to do so later. Many of us here have had our bacon saved by a spare duct or two that was put in 'just in case'.

 

If you don't make provision for wired light control and later realise that wireless only was not a great choice (or your wifi network has an issue), then you're stuck. If you do put in provision for wired control and decide not to use it, you can conceal and it's always there if you (or someone else) chooses to use later.

 

A networking rule of thumb is to use wired connectivity for things that don't move and wireless for things that do. That may be a bit old hat now but I have cat 6 everywhere and use a surprising amount of it for TVs, gaming boxes etc..

 

That sounds a good rule of thumb. However, I don't think WiFi is the correct wireless technology for home automation anyway. Definitely a sledgehammer to crack a nut (>10Mbps to send essentially 1 bit of data every few minutes at most). I do want to run a lot of Ethernet cable about the place, but that's not regulated (is it?).