Making my new home c-bus ready (in the building stage)

Hi,

I am currently finalising electrical for a house that I am building and would like to install some c-bus gear, unfortunately due to the way I have chosen to finance, the bank won't jump at including this in the loan , however they will allow me to put cat-5 in and terminate it in a krone patch panel under the stairs.

My question relates to what is require to make my new home "c-bus ready" so that when I have some spare cash I can start adding c-bus products to my new home as inexpensively and easy as possible.

Is it as simple as running cat-5 to each light switch, etc that I want to eventually add to the c-bus infrastructure or are there some things I can do with my electrical wiring that will help me along the way?

Cheers

 

Apart from the Cat5, which is easy and cheap (use Pink Cbus cable, not blue data cable)... The main hassle is to terminate the existing loads.

In conventional wiring, the power comes down to the light switch plates, then back up to the lights themselves. In Cbus, the power goes to a Cbus relay or dimmer (remote to both light and switch), and then to the lights. There is no power cables required behind the Cbus switches.

So, it's going to waste a bit of cable to make a retro-fittable installation, but not much money really (power cable costs WAY less than A$1 per metre, irrespective of what they'll quote you to add it)

My suggestion is to allow space for a number of "distribution boards" (dependant on size of house) inside cupboards. Bring Mains Power into those, and run cables from those to the lights, etc. Also run separate cables from the boards to the light switches. The more boards you can have, the cheaper the wiring will be

When it comes to changing over to Cbus, all the existing wiring can be re-used, except the switch wires which will need to be pulled out or terminated.

If the house has good access to the ceiling cavity, then I wouldn't really bother - I'd just install all the C-bus stuff up there and then completely re-wire the house for Cbus (mains, but not comms) at a later time. That would probably be a cheaper both now and in the future.

One important thing - make SURE to allow lots of "circuits" for the lights. The whole idea of Lighting Control is flexibility, scenes, eytc. If you have 1 light on 1 switch in every room, then you needn't bother with Control System.

For example, each bedroom in my house has at least 3-4 circuits (centre, wallwashing, spotlight of wardrobe, studying lights). The dining room has 3 completely separate lighting schemes, the lounge has 4. The garden has LOTS Because of the multiple lighting circuits I can switch on / mix them into and unlimited set of scenes.

My 2c - Cheers, John

 

Thanks John.

My biggest problem is that the house is 2 storeys with about 32 squares of living space, and that makes alot harder and alot more expensive to change things later on.

Would the cost of doing what you have suggested with standard lighting be high? Is it even able to still be done with standard lighting.

I was going to terminate all the datacabling under the stairs where I plan to install my rack, security system, etc. In you opinion would it be expensive or silly to see if I can get all the circuits/distribution boards wired back to there (which is where I would intend on putting the c-bus cabinent).

Basically I can probably fudge with the wiring a bit now if it would not be considered major changes (and I assuming wiring isn't really a major change) and hopefully save myself some $$$ later.

I am not intending c-bus just for lighting either, in future I would hope to connect external security shutters, irrigation, air conditioning and the security system, as well as anything else I can put in later.

Also, can the cat-5 be daisy-chained/in series or do you cable it put in a star like topology from a central hub (I assume this is the distribution board)?

Cheers

 

Hi again

First up - you cannot realistically change existing "standard" wiring to a "wired" Cbus system later. The methodology of the cabling is completely different, and major changes would be required - it is possible but really messy and disruptive (knocking holes in walls). You have to do it in reverse - wire for Cbus, then add on extra cables to make it work with standard wall switches.

One solution for you may be to use a combination of Cbus Wireless to do the lights as a direct retrofit - that is exactly what it is designed for - and traditional "wired" Cbus for the rest of it. It is the "wired Cbus" system that requires the most planning...

As I said above, the thing you must remember is that to make the Mains Wiring "C-bus ready" you need to wire up the house exactly like it would be for Cbus, then install extra switch wires that run from the (position of future) Cbus Cabinet(s) back out to the (temporary) standard wall switches. Then also have a Cat5 Cbus cable running between/to every switch.

One mains cable for every load (irrigation, lighting, blinds, whatever) needs to brought back to the Cbus cabinet, so that those cables can be connected up to the Cbus devices later. This can make it a real "rats nest" of cables and it's gotta be done very neatly and well documented so you can work out what goes where (most electricians seem to have difficulties at this point).

That said, it is usually more efficient and cheaper to separate the Cbus out into a couple of smaller locations... for example, irrigation : If you put all the irrigation valves out in the garage, you can put the Cbus devices that control them right next to them in a small box. In that case, the only extra cabling would be to allow 1 x Cat5 Cbus cable that connects between the house network and that garage position - everything else would be ready to go.

It is very common that all the Cbus devices be placed in a central location - I don't know what started that trend, but it seems to be the way most people install it. That is not to say that this is the BEST way to install it... the main disadvantage is that you need a humungeous cabinet to house all the gear, and also need miles of mains cables because every single load cable needs to be brought back there to one place.

I reckon the main reason it's done is because it looks cool - you can show your friends and say "and this (huge mess) is the Control System for the house". But doing it that way is the most significant problem in any large house (especially 2 story) - I recommend that you do NOT do that, but instead have at least 1 Cbus cabinet per floor, preferable 2 per floor. This will not increase the cost, but actually reduce the cabling cost and complexity. OK, it will not be as easy to show off to friends...

The only disadvantage of separating out the Cbus locations (apart from finding somewhere for them) is that there might be unused Cbus device channels... for example, if your irrigation control section only needed 6 relays, the only choice would be to use an 8 channel Cbus device which would leave 2 channels unused. Compare to everything in one location, where those spare channels could be used to control 2 fluorescent lights in a completely different part of the house (make sense?)

It is really hard to describe in words... do you have a basic understanding of how House Wiring and switching is done ?

*************

Regarding the Cbus cable topology, it does NOT work like a hub. The cabling can be star wired or daisy-chained... Cbus has a free topology so you can connect extra runs of cable at any point in the network. You do NOT bring multiple cables into any point. At every Cbus device you need 1 cable, and that cable must be connect to the network somehow. Usually a single cable runs up into the house, then splits off at a switch to make it's way around to all the other devices.

There are some limits (eg: max 1000 metres of cable per network) , but you are unlikely to find those limits in any normal house installation.

*************

I can give you a guestimate of whats involved... I just worked on a 5 bedroom house in Sydney that was about 40 squares over 3 stories (lower story was just garages, storerooms + 1 guest room). It had a relatively simple Cbus install (lighting only), and the Cbus Output Devices were mounted in 2 locations :
- 3/5 of it a rear storeroom behind the garage, that controlled the Lower Gorund and Ground floors
- 2/5 of it in the back of a walk in robe in an upstairs bedroom, that controlled the whole top floor.

That house used about $22,000 (retail) worth of Cbus - about 1/2 was in relays and dimmers, and there was about 90 separate loads. The other 1/2 of the money went into Saturn Ulti switches in most places and 11 x DLT switches in the living areas - those are probably the most expensive switches available but hell it looked cool !

That house used just under 1 roll (305m) of Cbus cable. The Main Cbus output devices were housed in 3 cheap chinese Distribution Boards, each 4 rows of 15 poles - each one was about 500mm wide and 750mm high. There was about 60 separate 3-core mains cables coming down to that location, I'd say the bundle of mains cables was about 150mm diameter. Upstairs there was another 2 of the same housings, and about 30-40 load cables.

That sounds ominous, and mains cable is cheap.. probably A$0.60 per metre or less, but there was still an absolute sh**load of it in there ! You can imagine that if another 2 separate Cbus Device Cabinets were installed, then the amount of cabling would have been 1/2 or even 1/3 of what was installed in that particular house.

*************

I think your next step is to read some published info, then contact a few local system integrators to make up a proper plan of action. It is probably best to consider a combination of Wired and Wireless - but note that wireless has some limitations, most importantly the fact that it can only control TWO loads from every switch position (even if that switch has 8 buttons, the other 6 buttons can only control lights that are wired up to OTHER switches).

All that said, I think it is completely feasible and would be relatively cheap (compared to the cost of the house) to wire a house tradionally but be ready for Cbus... however it is simply too hard to explain HOW to do it within this forum.

Anyway, that's definitely a long enough post for now - hope that helps you get a grasp of what's involved.

Cheers, John

 

Hi,

Ok, Understand now what you mean about how to wire for cbus and then adding the extra cables for standard switches

I am not keen on wireless anything to be honest, I understand its not ethernet but I work in IT Security and anything wireless makes me paranoid.

Now, I think understand one mains cable for every load, I am assuming this is similar to what happens now with circuit breakers back to the main power box, you have each different load on a different breaker?

I understand the smaller box idea, and it sounds like a good one, but does it mean you also terminate the load there? I am assuming so... I am not doing this to show my friends the control center, I would prefer to do the smart thing. And it could be said the proof is in the pudding, why would they care about where wiring terminates, when I press a button to change the lighting scene, etc I think that would be wow enough.

If I do go the smaller box idea, is it smart or stupid to have a box for each room? I don't mind a little extra cost and a little wastage if in the long run it would be the better idea. I am more a do it right the first time kind of guy because it usually saves you money in the end anyway.

Unfortunately I know bugger all about house wiring (digital I get, but electronics in general baffle me).

I get the feeling from your post that cabling to be "c-bus ready" (not installing any c-bus compenents) isn't really anymore expensive then conventional electrical cabling, would that feeling be correct?

I have read as much material as I can find, but unfortunately, I don't learn new ideas very well from reading, I learn alot more from talking to someone in the know.

Trying to find an integrator that I can chat to on a weekend has been bloody hard in Melbourne, and I can't get the time off work to visit during the day.

Thanks again.

 

John

I assume from this that you prefer to run a 2c+e for every "light circuit" as opposed to running a common n+e with a switch wire running to the light.

The second way was how the electrician did the last house I was in that had c-bus. The board was much neater doing it that way. The way you do it seems to clutter the board up and you require plent of room the terminate your (protected) neutrals.

PhoenixMage
Whit all the hassell this is going to create for you, have you thought about getting your finance elsewhere? You might say that that is a hassel too, but probably less than having to re-wire. I must admit I am very surprised at the banks statement about using c-bus. Maybe you need to present it to them in a different way.

Mick

 

Hi Mick,

Unfortunately, due to my current situation, beggers can't be choosers

At the moment it has more to do with pre-approval and market values and things like that. Its weird, they won't let me put in c-bus or down lights, and I had a fight to get datacabling put in, however for some reason a spa bath in the ensuite was fine.

Who understands banks anyway?

Cheers,

Tony

 

C-bus wiring

As another owner-builder who has not long finished (well, is a new house ever really finished?) building a new home, I'd like to throw a couple of comments (and questions) into the ring too!

Our home is somewhat different - it's virtually underground. The front faces south and is the only "exposed" side, everything else is under at least a metre of dirt. The house has a curved front but a straight back - so ranges from 15 to 20 metres deep and 55 metres long. Its construction is of concrete block (400mm wide x 200mm high x either 140mm (internal) or 200mm (external) thick). The outside walls are core-filled, but internal walls are hollow - and make a fairly easy way to drop cables vertically. The roof is a 200mm thick concrete slab, so access through the roof is impossible - and we've used a commercial grid system ceiling - the acoustic tiles make a hell of a difference inside, while allowing ready access to the ceiling space. The floor is a concrete slab with hydronic heating coils (3400 metres of it in 24 seperate loops). We ran most of our cabling on tray, suspended from the roof, and pulled some catenary wire to support the cbus, MATV, security and data cabling. Most rooms have at least 4 lighting circuits (eg, bedrooms have 4, the walk-in robes only have one, bathrooms have heat/light/fan, kitchen has 6 or 7). All the lighting (with a very few notable exceptions) are 240V downlights, with the GU-10 lamps removed and replaced with low power fluro lamps (did I mention we don't have mains power?). Although the fluros are not dimmable (yet), I chose to run 8-channel dimmer modules everywhere, because it gives me flexibility later. For example, the walk-in pantry has halogen lamps because it is only used for brief times, and it controlled by a PIR for those times your hands are full. Reading lights and feature lights, bench pendants and task lighting are still halogens (mostly 35W) and the dimmer features are very convenient there.

One of the other posts suggested running common neutral to all the lights and then running just active switch-wire from the c-bus to the load. We chose not to, as all the lights are downlight style, we fitted everything off to the insulation-displacement (quick-connect, crimp whatever you want to call them) fan-bases. This was amazingly quick - put ladder, climb up, strip, crimp, tek-screw fan base to roof, down ladder in about 90 seconds) - and with over 120 to do, this was a major saving in time. Pulling each circuit in red/black&earth and crimping was much faster and saved more in time and flexibility than a common neutral. Also, because of the number of boards we used (see later), we ran the cables in the brick cavity (150mm square) but only had to run at most, 18-20 cables down each. (It also gave us physical seperation for c-bus and power to each board - we mounted the 3, 24 unit boards side-by-side which gave us 6 cavities to get down at each site)

The whole house is a little over 80 squares, we split the c-bus over 4 locations (3 in the house area, where we have 3 x 24M clipsal boards each - two for the 3x8-channel dimmers and 1x12-channel relay, and one for all the RCDs, circuit breakers, main (sub) board switches etc.

We use the relays to control powerpoints to bedrooms, home theatre, bathroom light/fan/heatlamps, hydronics pumps, hot-water circulating pump, effluent treatment and only ever on/off loads like the 5 light circuits in the garage, the power for the garage door openers, relays to control up/down of each of the garage doors, water pumps, irrigation etc. We split the loads up so that there were "spare" dimmers and relay channels at each board, which was convenient since we've added some later.

The whole project used
* Power and Light cable: 2900m
* Video/TV coax cable: 600m
* CAT5 cable: 1100m
* CBUS cable: 580m
* Security cable: 800m
* 36 NEO switches
* 1 b&w c-touch
* 64 dimmer channels
* 60 relay channels

Although, we've run cable to allow for switches in at least 22 other locations we thought were "possible, later" and for 3 other "convenient, likely, when finances recover" locations for touch-screens.

If anyone is particularly interested, I'll post a URL for some of the several thousand construction photograps

All in all, it's been worth it in flexibility, but I'm fairly dissappointed with the amount of "overhead" power the whole c-bus system takes. With absolutely NOTHING turned on, it's pulling over 100 watts. That's over 2.4 KWH/day, which is a lot of power when we have to make every last watt on-site.

Hope this makes sense and is useful to someone!

RossW

 

Ok guys, but please don't abuse it....

http://house.albury.net.au/
Edited to add: I failed to say, click on the picture at the above URL to enter the site, and enter the username/password when prompted.
Username: cbusforums
Password: cbus


Some of the more relevant dates to look at would be:
12oct2004 to 29oct2004 (most of the hack work)
28nov2004
04apr2005 to 06apr2005 (fit-off)


*** EDITED ***
Sorry folks, the access to that site got pulled due to abuse, but I keep getting loads of requests from people wanting access. I've put up a small summary of the electrical stuff only at http://house.albury.net.au/cbus.htm.

The full site has over 5000 photos, most of which don't have any relevance to the electrical stuff.

 

It's not ME that wired it that way, I'm just the programmer

I think that the electricians do it so that they can identify the N + E for each (switched) circuit. There is a section in AS3000 that states that the N & E connections be clearly identified for each circuit... the use of a "looping" N & E would complicate matters (can you get 2-core black & green?)

Furthermore, it allows the "average wire-jerker" or apprentice to wire it up without thinking too hard. And it's much easier to write the load name on the wider white outer sheath

JC

 

Hi Ross,
I was interested to read about your experiences but not so happy to find out about the ongoing power consumption. I was actually thinking about this point when I found your post.

Can anyone point me to a summary of the expect consumption of the various devices? In particular, the consumption of the Dimmer units, the Relay Output units and the Neo and DLT switches?

We are planning a new house and we intend to use a grid connected solar system to provide some of our power needs (and feed the excess back to the grid when the house is not using all the solar output). However, I am interested to find out how much of that solar production would be consumed by the c-bus system. Also, do the relay units latch (ie do they only use power momentarily for the actual switching, and for the managment circuitry)?

I'd appreciate any info that can be provided or pointed at.

Thanks, Jeremy.

 

I haven't found any actual reference/list anywhere. One thing I have sort of worked out though, mostly from comments in these forums, is that the snubbers in the dimmers seem to have quite high "leakage" - several watts per channel - and with >60 dimmer channels, they all add up!

How much solar are you planning on installing?

The relays are latching, so they don't actually take more power just being "on". As I have a lot of NEO switches, I monitored the power draw with all the LEDs turned OFF, and ON at full brightness, and the difference, if measurable, was minimal. My inverter only displays the DC current down to 0.1A, and there wasn't any difference that I could see either way. The total power drawn by the input devices seems quite small. Their specification is 22mA I think, which is under a watt each. In reality, I think half a watt is closer to the mark.

Except that I don't have (a) room or (b) spare funds, I would like to try installing a relay channel in series with each dimmer. Set the relay thresholds so that it turns "on" when a dimmer channel is >0% and off when =0% and see if it makes enough difference to be worth it.

Overall, I think the cbus system is a good starting point. It has some good upsides: the CIS guys have been great whenever I've had a problem or failed hardware, and I love being able to "evolve" my house as and when we change the way we live in it. Automating manual tasks, simplifying others etc.

Downsides unfortunately are many. Cost, reliability, power consumption. Inability to practically interface with a bunch of other stuff in any meaningful way (eg, to display pressure or volts, amps, watts etc). Lack of "flexibility" at a device level. Sure, you can fork out $700 here and there for extra "logic" modules, but sounds like they have a pile of limitations themselves.

Would I do it the same way again?
Well, probably. Although I'd split the place up even more. Having everything concentrated into 4 places is still too high density and used a lot more cable than was probably warranted. I still have not finished getting my own interface software written, which will let me do all the logic and so on "elsewhere" and use something better/nicer than the B&W CTouch and much less expensive than the colour touch screen. The place "works" well enough for now, I can add all the nice stuff when its too hot to work outside.

 

just a thought

When i wired my place for c-bus a couple of months ago, as all the walls are lined with polyester insulation batts, what i ended up doing was running a "ring" of c-bus cable through almost every wall at about 1100mm, and left some slack every now and again, with the price of the cable (i.e. very minimal) and the frustration of trying to get down the walls later i figured that being able to cut a hole in the wall wherever i want a new switch and finding the cable already there was a huge time saving. Obviously i also have cables in the roofspace as well. but have added a few things over time, but the initial effort sure saved time.