Flood wiring questions for newbie

[Mal79]

Hi all,

A few months ago me and the Mrs bought a 3 bed house which needs decorating in all rooms. I decided that a wired home network is needed and by hook or by crook I ended up here! Now the "want" list includes whole house audio and media, lighting, heating and so on...

It is likely that node zero is going to be in the loft space and my questions today concern the routing of the data/coax/audio cables. I haven't been able to find the specific information I am after on this forum or the net, so apologies in advance if these are basic questions.

Firstly, dropping the cables between loft, first and ground floors. We have some plastering that needs to be done and I want to make provision for the cables in the walls before that happens. I am thinking along the lines of conduits in the wall's "safe zone" that will take that room's services, then route the cables under the floor and up to various wall outlets as required (much like power outlets). Is this the correct way to do this or will I need to drop cables to each outlet?

Whilst on the subject of dropping cables, how should they be secured in the conduit/cavity to avoid the weight of the cable straining itself? And are there any things I should bear in mind about running cables together, especially if I plan to run speaker cables as well?

Secondly (or even fourthly?), running cables under floor. I have seen on various sites, cables going through joists as a means of supporting them in the floor cavities. However I will need to run many cables parallel with the joists and haven't seen how this should be done. I guess we could herringbone the floor structure (probably need to for node zero) and go through the noggins, but if there are other ways of doing this I would love to know!

I want to make sure that whatever I do doesn't contravene wiring regulations and that I do it in such a way that it gives me flexibility to change the HA project in the future.

Thanks in advance for your expertise.

Malcolm

[toscal]

Drain pipe or guttering works well for laying cables in. I have a 2inch soil pipe going from one part of my house to an out building, this was laid as a just in case. The electrics are in another conduit.
Also proper cable trays work well, but can be pricey.

http://www.minitran.co.uk/pages/products/list.mhtml?ct=3&sc=108

http://www.cmwltd.co.uk/index.php?main_page=index&cPath=49_50

http://www.thesitebox.com/Category/4061/light-duty-cable-tray.aspx

[Mal79]

Drain pipe or guttering works well for laying cables in. I have a 2inch soil pipe going from one part of my house to an out building, this was laid as a just in case. The electrics are in another conduit.
Also proper cable trays work well, but can be pricey.

http://www.minitran.co.uk/pages/products/list.mhtml?ct=3&sc=108

http://www.cmwltd.co.uk/index.php?main_page=index&cPath=49_50

http://www.thesitebox.com/Category/4...able-tray.aspx

So for underfloor cables, it is suitable to run a tray parallel to the joists. This would then be either attached to a single joist or suspended between two?

In terms of wall conduit, I see that 25mm tube seems to be the largest that is available. I had envisaged something more box section to take all the wires, perhaps a bit like in wall trunking - hey ho... I reckon I will need to have a few conduit pipes in the wall - hopefully make cable groups a bit more logical.

[toscal]

You can get square trunking, we have used it on installs. We normally use it where we need to get access to a large quantity of cables such as the back, or bottom of the patch panel. What we normally do is the conduits go into a rectangular box then the square or rectangular trunking leaves the box. It makes pulling cables easier as we can pull them out or feed them from the box.
Also remember no more than 2 bends in your conduit or trunking. If you need to have more than 2 bends then fit a junction box between the 2nd and 3rd bend.

[TimH]

Firstly, dropping the cables between loft, first and ground floors. We have some plastering that needs to be done and I want to make provision for the cables in the walls before that happens. I am thinking along the lines of conduits in the wall's "safe zone" that will take that room's services, then route the cables under the floor and up to various wall outlets as required (much like power outlets). Is this the correct way to do this or will I need to drop cables to each outlet?

That's how I did mine
I had to construct a new stud wall so I built-in a couple of plastic waste pipes to carry cables between the attic space and ground/first floor void. If you're going to locate your node zero in the attic, think about using high-capacity ducting, e.g. this flat ducting http://www.tlc-direct.co.uk/Main_Ind...t_6/index.html

Aim to have your ducting no more than 50% full to give you options for future expansion.

I ran cables in the floor/ceiling void and then up/down to outlets as required.

Whilst on the subject of dropping cables, how should they be secured in the conduit/cavity to avoid the weight of the cable straining itself? And are there any things I should bear in mind about running cables together, especially if I plan to run speaker cables as well?

I carefully bundled my cables together, applied a cable tie and then fixed that to a "U" staple hammered into the side of the joist. Watch that you don't over-tighten the cable ties and crush the cables themselves.

Secondly (or even fourthly?), running cables under floor. I have seen on various sites, cables going through joists as a means of supporting them in the floor cavities. However I will need to run many cables parallel with the joists and haven't seen how this should be done. I guess we could herringbone the floor structure (probably need to for node zero) and go through the noggins, but if there are other ways of doing this I would love to know!

Guttering or cable tray are pretty good, as toscal suggests. There's also cable basket - a more open form of tray, e.g. http://www.tlc-direct.co.uk/Main_Ind...ray/index.html

I want to make sure that whatever I do doesn't contravene wiring regulations and that I do it in such a way that it gives me flexibility to change the HA project in the future.

One key one - make sure you always have a physical barrier between mains cables and LV cables(1), or at least a 50mm air gap. In practice this means using separate trunking for drops in the walls and securing mains / LV cables to opposite sides of the joists. The intent is to stop mains voltages appearing on LV cables in the event the insulation breaks down.

The exception to this is where the sheath of the LV cable is certified to "resist" mains volatages. Pink CBus Cat5 cable is like this, as are some others, but most generic Cat5 will not comply. Similarly you need to check your coax & speaker cables, or observe the required separations.

My ceiling to floor drops were done in 25mm x 16mm trunking with a clip-on lid. I used this;

http://www.tlc-direct.co.uk/Main_Index/Trunking_Pvc_Index/MiniTrunking_2/index.html

I chased-out the blockwork walls, installed the cables, fitted the lid then plastered over. I found I got more capacity with the square than the round cross section.

Good luck, and don't forget to take plenty of photos

Tim.

[toscal]

As Tim said take plenty of photos. This has many benefits. And is a good way to check if you ever need to do work on a wall that you know has cables in it as the photo will give you a good idea of where they are. Never had much success with one of those stud / cable finder things.
One last thing to bear in mind is fire breaks or whatever they are called. If you have open conduit going from one floor to another you may have to seal the conduit . This is to prevent air feeding a fire or the passage of smoke to other areas of a house.
Insects may be a problem the conduits make nice cosy runs. We have had on occasion ants nesting in photocells for automatic gates. A quick spray and then leaving a couple of those ant/ ****roach motel things in the odd junction box makes sure that they never come back.

[Mal79]

Wow, more than a year has passed and still no cables in the walls! Far too much procrastination... However I have a plasterer booked next month to do a couple of rooms, so I now need to get a move on! As before I turn to you guys for advice and experience.

So a quick recap on the house then: Victorian Terraced, Two levels + Loft, decoration and electrics perhaps cutting edge in the early 80's . Thankfully we had Central Heating fitted last October... I intend for the loft to be node zero and have booked an electrician for the week prior to the plastering for a new CU and some power circuits to the loft. The rooms that are being plastered next month are main bedroom and hallway/ landing (up and down).

My first thoughts are with the drops loft down into main bedroom, having enough capacity to serve the bedroom plus drops to the living room and downstairs hallway. I was thinking that cable drops in the safe zones would provide the greatest flexibility as I haven't quite worked out all of my data needs yet (especially for the top hall/landing area). I want to avoid having to work in the eaves, so won't be putting cable drops at the outside corners of the property. The floor plan below should explain this a little better:



On the ground floor hallway, I envisige needing data cables for alarm/cctv/doorbell(!), however the safe zones in the hallway aren't in the same place as the bedroom above. I intend to run the cables along the joists ("east-west" in the pic) in the main bedroom then down the second drop to the hallway. The drops to the though lounge will be done when we do that room:



So to the questions...

• Do my plans above seem OK? I am planning to run two cables to each corner of each room and "several" to the hallway.
• Should I be going for a separate Consumer Unit in node zero (electrician has offered this option)?
• What size consumer unit should I looking at for node zero and the main board?
• I am also considering a "Lamp Circuit" in the bedroom, switchable from a second switch on the main switch. Would this be worth the extra effort?
• Any tips on cutting chases? Last one I did to reinstate light switch back on wall (previously had been moved to built in wardrobe) was with a chisel and lossened a lot more plaster than I wanted. Angle grinder perhaps?
• How do I secure conduit/trunking to wall prior to plastering?
• I have seen 40 x 16mm trunking in B&Q similar to the stuff in the TLC link in TimH's post. Would this be suitable or should I instead use multiple smaller trunking?
• I am looking to use Cat 6a data cable to ensure a resonable life span of the network. Is there anything I should pay special consideration to? Any particular recommendations on cable brand?

That should be all for the moment!

Thanks, Mal

[toscal]

Why no data points in the kitchen, bedroom 2 and 3.
The consumer unit size depends on what you want to put in it. Will you be using it for din rail mounted RJ45 sockets. If you are then count the number of sockets you need then double it. This will allow for expansion, and the placement of Cat5 to whatever boxes to possibly fit into the consumer unit. You can get special trays that clip on to the din rail to allow things like routers and power supplies to fit into the consumer unit.
If you can allow for easy expansion of adding more cables as time progresses. You will be surprised how quickly you find uses for all those RJ45 sockets you have.

[Mal79]

Why no data points in the kitchen, bedroom 2 and 3.
The consumer unit size depends on what you want to put in it. Will you be using it for din rail mounted RJ45 sockets. If you are then count the number of sockets you need then double it. This will allow for expansion, and the placement of Cat5 to whatever boxes to possibly fit into the consumer unit. You can get special trays that clip on to the din rail to allow things like routers and power supplies to fit into the consumer unit.
If you can allow for easy expansion of adding more cables as time progresses. You will be surprised how quickly you find uses for all those RJ45 sockets you have.

The plans above are mostly focused on the cabe runs and data points in the areas that are shortly due to be plastered. The plan for other rooms is much the same - 2 x points at each corner of each room. The kitchen plans are as yet undecided, but I will work towards at least the same provision as the rest of the rooms.

The 2nd consumer unit in the loft will be for mains power rather than data, so I have flexibility to add more systems as time goes by. I would rather do this now rather than later and find I have to put more chases in our walls! I will likely use server cabinet for my data needs.

10 days to go, lots to do. Arghhhh!

[TimH]

You definitely don't want to underestimate the data runs to the kitchen, as I'm sure someone else will chip in too

Just a couple of comments from having been there & done it -
- the 25x16 trunking I used, while not overly generous, was much easier to install that the 40x25mm I used for runs to our TV - that needed a lot of chasing out to sink it deep enough.
- hire a proper wall chaser to do the runs (e.g. http://www.screwfix.com/p/erbauer-er...ser-230v/81200). It'll make loads of mess (so mask of the rooms well) but is so much easier than chain-drilling & chiselling. An angle grinder will be even messier still as the wall chasers are designed with a shroud around the blades and a vacuum extract nozzle.
- invest in an SDS drill (http://www.screwfix.com/p/titan-ttb2...ill-240v/97533) and some "skirting board" chisels (http://www.screwfix.com/p/armeg-sds-...sel-20mm/15097) - this will make short work of chipping out the waste between the vertical lines. You don't need an expensive one - I have a B&Q "Performance Power" drill and its fine for the limited use it gets.
- make sure you have a good vacuum cleaner, or hire one. Chasing walls is incredibly dusty!
- When I did mine, I installed cables in the trunking before plastering over - it's just that bit easier to lay the cables into the trunking with the lid off rather than trying to poke them down (effectively) a blind tunnel.
- Measure your cable runs and make sure you have enough cable ready to go. I underestimated my coax lengths and had to make a quick dash to the supplier to get several more reels in!

HTH,

Tim.

[Mal79]

You definitely don't want to underestimate the data runs to the kitchen, as I'm sure someone else will chip in too

Just a couple of comments from having been there & done it -
- the 25x16 trunking I used, while not overly generous, was much easier to install that the 40x25mm I used for runs to our TV - that needed a lot of chasing out to sink it deep enough.
- hire a proper wall chaser to do the runs (e.g. http://www.screwfix.com/p/erbauer-er...ser-230v/81200). It'll make loads of mess (so mask of the rooms well) but is so much easier than chain-drilling & chiselling. An angle grinder will be even messier still as the wall chasers are designed with a shroud around the blades and a vacuum extract nozzle.
- invest in an SDS drill (http://www.screwfix.com/p/titan-ttb2...ill-240v/97533) and some "skirting board" chisels (http://www.screwfix.com/p/armeg-sds-...sel-20mm/15097) - this will make short work of chipping out the waste between the vertical lines. You don't need an expensive one - I have a B&Q "Performance Power" drill and its fine for the limited use it gets.
- make sure you have a good vacuum cleaner, or hire one. Chasing walls is incredibly dusty!
- When I did mine, I installed cables in the trunking before plastering over - it's just that bit easier to lay the cables into the trunking with the lid off rather than trying to poke them down (effectively) a blind tunnel.
- Measure your cable runs and make sure you have enough cable ready to go. I underestimated my coax lengths and had to make a quick dash to the supplier to get several more reels in!

HTH,

Tim.

At first I struggled to think of what data needs I would have in the kitchen (thinking along the lines of touchscreen interfaces). But then again I realised, it has the most electrical gadgets in any one room. No doubt I will want to control everything!

I am due to pick up the chase cutter tonight, so will have a lot of fun with dust. I had kind of figured that the thinner trunking would be easier to chase so I will do 2-3 chases in the "main" locations. I guess No More Nails will be adequate to fix the trunking prior to plastering?

Unfortunately I dont yet have cable to fit in the trunking (a planning oversight), so will have to be brave and pull through after plastering. I am partly doing the HA stuff to gain experience in this area, so I don't want to make things too easy...

Just a couple of questions:

• is it correct to use the plastic back boxes behind data faceplates?
• will Cat6A cable be overkill - would Cat5e make more sense (given that it is an improvement on having no data provision presently)?

Thanks

Mal

[Geps]

Use screws and plugs to fix the trunking. Trunking is a flexible plastic channel and the worse thing for plaster is anything that flexes. If you don't fix it securely enough when you push through your cables and cause it'll to move - you'll stress the plaster and possibly cause it crack.

As for cable go for the most runs, of the highest quality you can afford that you can practically fit in.

[gazza_d]

Always chuck in the highest quality cable you can. If I was running network cabling now, I would install gigabit standard. It will be a long time before we need anything else in a home environment, and gigabit routers/switches are now very reasonable.

the other thing is whether you are installing enough data points.
You can run all sorts over RJ45 besides networking. Phones, 1-wire interfaces (temps etc), Video and Audio using converters.
Again in my situation I would install 4 modules in a double gang modular plate, where previously I installed one or two several years ago.
If the budget is tight, then at least lay the extra cable in the walls, identify the ends, and leave unterminated - you can then easily add more networking if you need to later. Putting cables in walls is the hard bit.

[Mal79]

Use screws and plugs to fix the trunking. Trunking is a flexible plastic channel and the worse thing for plaster is anything that flexes. If you don't fix it securely enough when you push through your cables and cause it'll to move - you'll stress the plaster and possibly cause it crack.

As for cable go for the most runs, of the highest quality you can afford that you can practically fit in.

I am using the trunking with the clip on cover - can I screw through the "back" (taking care to countersink the screws), then add the front cover? Or should fix with a couple of screws either side? In fact, I think I will do the later anyway...

Looking at the size of the trunking, I am going to need a fair few drops in order to squeeze enough Cat 6A through. Unless I can find some "slim" cable that is.

Always chuck in the highest quality cable you can. If I was running network cabling now, I would install gigabit standard. It will be a long time before we need anything else in a home environment, and gigabit routers/switches are now very reasonable.

the other thing is whether you are installing enough data points.
You can run all sorts over RJ45 besides networking. Phones, 1-wire interfaces (temps etc), Video and Audio using converters.
Again in my situation I would install 4 modules in a double gang modular plate, where previously I installed one or two several years ago.
If the budget is tight, then at least lay the extra cable in the walls, identify the ends, and leave unterminated - you can then easily add more networking if you need to later. Putting cables in walls is the hard bit.

I figured that if I am going to go to the trouble of putting cables in walls, then I may as well put in high quality cable. Can't quite stretch to "Cat 7" ( the unusual connectors put me off a bit too), so going with Cat 6A. I am planing to put 2 outlets in each corner of rooms, but will put some extra cables in for future expansion.

Once the cables are in the wall, I then have to face the decision(s) of what on earth to connect to them!

Mal

[TimH]

I guess No More Nails will be adequate to fix the trunking prior to plastering?

<snip>

Just a couple of questions:

• is it correct to use the plastic back boxes behind data faceplates?
• will Cat6A cable be overkill - would Cat5e make more sense (given that it is an improvement on having no data provision presently)?

Thanks

Mal

I used screws & plug to fit my trunking - nothing too serious, perhaps one screw every two feet, just enough to hold the trunking in place. The trunking was also a close fit in the chase (not tight, but minimum gaps at the sides) so any sideways movement would be resisted. A glued solution *might* be ok, depending on your specific installation, how deep, etc. but I'd recommend screws. I didn't countersink mine and fixed through the back of the trunking only. Make sure you fit the lid correctly to give a secure channel for the cables.

Not sure about the plastic box question - I used galvanised steel back boxes in blockwork walls and plastic drylining boxes in stud walls, whether it was mains power or LV/data, i.e. the box type was determined by the wall construction not the cable type

Cat6 would be fine, but it is more sensitive to correct termination than Cat5e - i.e. it's easier to screw-up a cat6 installation vs. cat5. I used cat5e throughout and had no problems, partly because it was easily available and is was significantly cheaper. Are you going to install Cat6 faceplates and patch panels too?

One further point, given that you're pulling the cables through later you may find it easier to pull through all cables for that route as a single bundle. If you try and thread them individually you may find they get caught up with each other and they're harder to pull through.

HTH,

Tim.