First Cbus Install.. scary stuff!

Hi All,

I have started purchasing equipment for my first cbus install in my house and am now getting a bit nervous about the calculations I have made .. not being an electrician. I have been on the cbus course in the UK but unfortunately it is only a 1 day course now and no wiring is discussed as the courses are geared up for electricians who know what they are doing as far as the wiring is concerned and the whole course was pretty much entirely about programming the software.

Here is the list of components I am ordering

1 x 12 Channel Voltage Free Relay with power supply 10A
1 x 8 Channel Dimmer with power supply 1A
1 x 4 Channel Dimmer with power supply 2 A
1 x PC Interface
6 x Saturn 5 Gang key input DLT
9 x Saturn Range, 6 Gang Input
1 x bus coupler to link to pressure mats for stair lights
1 x Indoor PIR Movement, Light level & IR Combined Sensor
1 x Infrared Controller, E2000 Series, 4 channel

1 x Homegate software
1 x clipsal universal remote

I have worked out that I probably do not need one of the dimmers to have a power supply but there?s not a lot of difference in price to have a power supply included compared to adding a separate power supplying if I add more units later. I have not included the dimmers and relay as units in my calculations (not sure of this is correct) and so have only included 18 units needing 36 mA of current across the network, I believe my network will have 60 mA ? is this excessive or wrong?.

What I am mot concerned about is working out if the 8-Channel Dimmer, 220V AC, 1A is the right component for the type of lighting I am using. I am specifying standard household lighting, a mixture of halogens and ceiling pendants (no strip lighting) but some if the rooms are quite large the kitchen may have up to 16 halogens, which I have gussed I can use 1 channel on the dimmer or the lounge will have 3 ceiling pendants again I have assumed I can use 1 channel for this? I do not know the wattage of the bulbs etc at the moment, someone is helping me with this, how do I work out if the 1 amp is enough .

Any help would be very much appreciated, if it is to tell me I have worked this out completely wrong or my system is poorly designed, I am pressuming this is a very small system.

Thanks in advance

Lee

 

Hey Lee,

First and foremost, you should NOT be doing ANY of the 220v wiring for your house without being a licensed electrician!!!

If you are simply on here so that you can work out the non-mains wiring for C-Bus, and to do the programming, then fair enough, but please, for your sake, and the sake of the ones you love, have a licensed electrician do the mains side of things for you.


Regards,

Darpa

 

Also,

In regards to your lighting,

I am assuming you are talking about the 50 watt low-votage dichroic halogen downlights. If these are the ones you are talking about using in your kitchen, then no, one 1A dimmer channel is not nearly enough.

You would only be able to run roughly FOUR (4) lights per channel, as each draws 50 watts, whereas a 1Amp channel is only capable of controlling roughly 220 watts in your situation.

Volts (220) x Amps (1) = Watts (220x1=220)

This would mean that if you were going to install 16 x 50 watt downlights in your kitchen, you would need 4 dimmer channels to run them all.

The same thing goes for your pendant lights, if you have 3 fittings, as long as you keep the total wattage of the globes below 220 watts total, yes, you could use one channel on the dimmer, but this would limit you to no more than 70 watts per fitting. You would be far better off with the 3 pendant fittings spread across a minimum of 2 dimmer channels, allowing the typical brightest globes (100 watts) to be used with no problem. using 3 dimmer channels would be even smarter. Also, you need to consider that if you decide to use one dimmer channel now, and later on you decide that 60 or 70 watt globes arent bright enough, you wont be able to use brighter ones. Thus why it would be a very smart idea to use 2 or 3 dimmer channels to control them.

I hope this is of help to you, but please, get a licensed electrician to do the work for you!!


Kindest Regards,

Darpa

 

I wouldn't do this.

The transformers are not 100% efficent.

I would use a 2A device instead.

 

Fair point rhamer

I know they arent 100% effecient, its just that I have found wen using the newer electronic transformers, that if there is at least a 10% margin between dimmer capability, and power consumption, that generally 95% of dimmers dont have a problem handling that kind of load.

But to anyone else reading this thread, I stll agree with what rhmer has said.


Darpa

 

Old wire-wound transformers = allow 15 watts loss, so 1x50W lamp = 65W.

1 amp @220V = 220W, so you can use THREE downlights per channel

Electronic transformers are different - depending on the design you can use ZERO, 3 or 4 per dimmer channel. That depends on the Input Capacitance of the particular product.

In Australia, 4 x 2A dimmers are half the price of 8 x 1A so it makes sense to use 2 Amp everywhere (since they are about the same price per channel). In the UK the 2A works out almost double the cost per channel.

The downside is that with 1A dimmers, you use a lot more channels !

But for flexibility, I'd keep the groups of lights small (3 or 4 maximum) per dimmer channel. If there were (say) 12 lights in a lounge room on 4 channels, you can assign those 4 channels the same group address and make them all dim together, or you can assign different groups and make them independant.

How the lights are HARDWIRED is what affects the flexibility of the control system. So, the more that rooms are "split up" then the more flexibility you have to change things later (in software). If you wire every light onto one circuit, then there's nothing you can do later.

John

 

Hi Lee,.

A few bits of advice from a fellow UK CBUS owner

I am assuming you are just speccing this stuff (as I did for my electrician) and having an electrician do the wiring for you - the new Part P regs do not allow the 'layman' to do the wiring and it all has to be signed off and tested before sale / buildings control will sign off anyway so you are kinda stuck.

I managed to run 4 halogens of a 1 amp and 6 off a 2amp. You need to get into the type of transformer you are using to make sure you can do that many - if you are not careful it will be less. I can dig out the part number of mine if you need it - its generally available and about ?5 each.

If you need more you need to look at the 5Amp dimmers but I would suggest if you want 16 of them use 4 channels of a 8way 1amp dimmer and simply the group the loads together. Better still do some moooooood lighting.

If you can afford it I would put dlt's everywhere as they are soooo flexible with the LCD text. You will be suprised how many uses you can find for them and having them labelled makes all the difference to someone who is not used to your house.

Not sure what you want the IR for - we did not bother but you may have a reason. We have a few more sensors for automating lights in loo's and in the front and back garden.

I would also suggest a PAC rather that a PCI - I beleive you can program CBUS with both but the PAC allows you to do some cool automation.

If you want some more help or the number of a very good, reasonably priced electrician (who did my whole install) give us a shout.

One final comment - if you are wiring the whole house, make sure you wire every light back to the same place even if you are using conventional lighting to begin with. It will allow you to replace things later.

Chris

 

Oh and what does Homegate do for you ?


Chris

 

Great response.. thanks

Thanks for the responses. really useful help!.

Firstly I am getting an electrician to do the wiring although I was planning to wire the low voltage side myself ... but thanks for the concern

The information you have all supplied is excellent I will have to look at my plan again and order extra dimmers? the bad news is my wife is going to go mad!!!!!!! when she sees what I have spent so far let alone what these changes will make. Seems a bit unfair that in the UK the 4 channel dimmer is almost the same price as the 8 channel.

I have a plan? might not be a good one but here goes. I didn?t realize if I use low voltage halogens I can have less wattage per bulb and so may only have to use 16 x 35w halogens? the downside is I will also need to have dimmable transformers, so am going to work this out to see what?s the cheapest way to do it.

I will look at getting more DLT?s and making the most of having more channels for some moody lighting. The IR is to use with the universal remote just for the main bedroom.

I am using homegate as I am planning to have a pc permanently connected to the cbus system and the PC will be connected to a couple of PC touch screens, not sure how this will turn out yet but if it does will be a very cheap alternative to having clipsal colour screens.

 

Hey Stonecold.

When it comes to the Electronic (Versus Iron-Core) transformers, they usually come in ratings of 60w and 105w, which means that if you decided to use 20w globes (for example), you could run 5 of them per transformer, or 2 x 50w globes. I wouldnt recommend using 3 x 35w globes though, as its not a good idea to leave no headroom.

When it comes to dimming the low-voltage lighting, the way you need to look at it is that there are two different "types" of dimmers. These are called "Trailing-Edge", and "Leading Edge" dimmers. As far as I know, the C-Bus dimmers are only available in the "Leading Edge" design, which means that you wouldnt be able to run Iron-Core trannies off them anyway (As they require "Trailing-Edge" dimming).

But just as a tip, and I'm not sure what the availability of these trannies in the UK is like, but there is a well-known lighting company called Nelson, and they make several transformers in both 60w and 105w version, which are suitable for both Leading-Edge AND Trailing-Edge dimming.

I just personally feel like using 35w globes would be a waste, as you would have a ton of unusable transformer ability left over, whereas if you used standard 50w globes, and the 2A dimmers to match, you would be able to run up to about 8 x 50w globes per channel.

Pretty much any electronic transformer will be dimmable from a C-Bus dimmer, just check before you buy them that they are "Leading Edge" dimmable


Kindest Regards,

Darpa

 

C-Bus Dimmers are only (currently) available in Leading Edge. Iron Core transformers require Leading Edge (not Trailing Edge). Electronic Transformers (technically) should only be dimmed with Trailing Edge, which is something not available from C-Bus. Only SOME electronic transformers can be dimmed with Leading Edge, but there are limitations - see further below

35W Osram "IRC" or Philips "Masterline ES" lamps give much higher output than conventional lamps. In fact, you can get the same performance from a 35W in one of those lamps as a conventional 50W. The only downside is that if you exploit this lower loading to put more on each dimmer channel, you need to remember that at re-lamping time (and not fit standard 50W lamps in there).

Oh, and electronic transformers are so cheap that "excess capacity" is really not a major concern. A 70VA or 105VA electronic plus 2 x 35W IRC lamps is cheaper to purchase than 2 x wire-wound transfomers plus 50W lamps.

This is not strictly correct - there are considerable limits on the Electronic Transformers that can be used with C-Bus. Primarily, with most designs you have a limit of the NUMBER of transformers that can be used on each channel (this is separate from the Power Loading - for example, using Osram HTM105 transformers you can only useSearch this forum for "Electronic Transformers" or refer to these threads for more info

http://www.cbusforums.com/forums/showthread.php?t=2223&highlight=electronic

http://www.cbusforums.com/forums/showthread.php?t=1770&highlight=electronic

and there's a lot more threads in here about it too.

And this is some CIS info/ literature on dimmers in general :
http://www2.clipsal.com/cis/technic...newsletters_and_faq/technical_info_on_dimmers

And one specific to dimmers and transformer compatibility :
http://www2.clipsal.com/cis/technical/technical_support/newsletters_and_faq/transformers

Download the 2 x PDFs linked at the bottom of the second page for the techo details.

Cheers, John

 

Ok,

I think I need to apologise, it looks like alot of the research I did before commenting was incorrect, so I apologise for that.

I think I need to learn to keep my mouth shut and let people like JohnC answer questions in future. My apologies to all those concerned.

Regards, Darpa

 

Darpa don?t apologize ! trying to help is not a bad thing I appreciate your help and advice!

I now realize how little I know! ... Thanks to everyone who has helped I didn?t completely cock up and process my original order. .. never ceases to amaze me how online communities help each other for free.

John, thanks for your advice I will research the links and advice you have given and am starting to feel much more confident about my first install.

Thanks

 

Iron Core FTW !!!