Re: Lights, cabling, CBus, etc.

["Richard Boreham" <richard.boreham@xxxxxxx>]

In response to some of your questions below...

We used main's voltage halogen in building a house because we use X10 for
control and I was worried about interference from the transformers.  I can
confirm that they give no problem with interference (in my experience) and
we have about 80 throughout the house.  They can be dimmed with no trouble.

Couple of points to be aware of.  The main's voltage halogen do not give
the
ultra white light of the low voltage ones, they are a little more reddish
(but not as much so as regular tungsten filiament).  Its not actually an
issue at all - you are unlikely to notice it in practice.

Also, the mains ones are not as powerful so you are likely to need more
than
of the low voltage variety (I seem to think its something like 25% but I
can't remember the source of that).  For example, in our 6.5m x 3.5m lounge
we have 11 x 50w downlighters in 3 circuits.  Full on that burns 550w, but
we never use them like that!   They are set up in scenes and we probably
have around 250w on max (usually somewhat less); the most popular is
probably 150w but is much subtler than a couple of 75w 'danglers'.   So my
advice is to (way) overspec the absolute number of units but use the
sophistication of your control system.  In this respect, it's therefore,
probably worth setting the lights into several cbus circuits from the
outset
rather than coupling them into one at the start.

I remember well the amount of cable and complexity we had by running star
wiring for lighting (no wonder that the ring system is the usual).  It may
well be worth doing a bit of up front compromising to reduce the complexity
of the circuits and shear volume of wire.  For example using (say) 3
circuits to the lounge rather than the intended 6 may save a lot of effort
without compromising the ability to do good scene control.  Assuming you
are
also putting in wall switches it means you have less complication (and
cost)
there too.

I'd check with an electrician (I'm not) but I think 2.5mm is used for
radial
power circuits (to 20 amp) - it might be overdoing it for lighting
circuits.

Advice from our electrician was to ensure the downlighters were of the cast
variety, not pressed steel - not sure what the screwfix ones were like
(Screwfix do seem to have the best price on the bulbs though and the Osram
ones seem to last well and have a whiter colour than some of the cheaper
ones).

We used Green Island for our units (www.greenisland.co.uk).  Their units
seem to be pretty good and they gave us a good discount on a bulk purchase.
They will also produce a lighting design if you have a scale houseplan they
can annotate.

Regards

Richard


Message: 5
Date: Mon, 07 Apr 2003 10:01:47 -0000
From: "davidsussmanuk" <lists@xxxxxxx>
Subject: Lights, cabling, CBus, etc.

After a long, long delay I'm finally ready to start cabling for the
new lighting. Knowing diddly squat about this (although I have been
on the cbus course), I wanted to ask a few questions. Background
first though. It's a retrofit CBus install, in the house I'm living
in so I can't just strip out the old lighting circuits and replace
them with cbus ones - I need to gradually change over, on a room by
room basis. Walls are all brick (all the way up to the roof), ground
floor is concrete, and 1st floor boarded.

I have two choices for the downstairs lights - chase the upstairs
walls and run the mains up and around to the N0 point in the loft,
or run them along under the boards to a central point and then up to
the loft. Neither option is great - 1 more mess & replastering (but
I'll be doing some of this anyway), and 2 mens flooring and drilling
joists. Given that I'm switching from 2 dangling lights in the
lounge to 6 halogen downlights (I'm not one for dangling lampshades,
plus you get better light) I'm worried about drilling too many holes
through joists. I want to run a single cable for each halogen, even
though I intend for this to be one circuit to start with. A cable
for each gives me the flexibility to split it into multiple circuits
at a later date. 6 cables through multiple joists is a bit worrying.

And leading on from that, what cabling should I use for the lights.
Is 2.5mm T&E suitable? Also, for the cat5, I know Clipsal recommend
their own, but are there other sources of lsoh/coloured cable to the
same spec?

For the halogens, I wanted to use mains powered, to avoid the buzz
that LV ones generate when dimmed. I presume there's no problem
about dimmming the mains ones? I'm thinking of something like the
standard halogens, such as those on p70 of the Screwfix catalog
(vol70), although I'd gladly accept advice on better ones.

As an aside, did you know that Clipsal are developing a retrofit
switch for CBus systems? RF switches and an RF control unit. Tail
end of the year if they get it working. They also have a UK alarm
system planned for the summer. Anyone know anything about this?

Thanks (and apologies for the long rambling post).

Dave