cjbeattie wrote:
hi guys...

Hi!

just new to diy and to this site so go easy please....

Will try.. ;-)

ive read about this 'transformer' for the last posts... im planning on
putting four downlighters into the hallway of our house and also
wondered if i could run them from the orignal light fitting.. i take
note of the plant pot idea and will do that... so not to set the house
on fire....

what exactly is this transformer? and where would i purchase one from?
and what is the best way to wire these things up so it can be ran from
the exisiting single wire.. many thanks

OK downlights come in two basic flavours, mains ones and 12V ones. The
mains ones, as the name suggests, run directly from the mains and don't
need a transformer. The 12V ones need something to step down the mains
voltage to 12V. This is traditionally a transformer. Also readily
available are so called "electronic transformers" which are smaller and
lighter but do the same job.

If you go the mains route then you simply need to replace the existing
ceiling rose with a junction box and wire out from there to each light
position. You can use a combination of "star" wiring, or daisy chain,
whichever is simplest.

With a transformer you can do it the same way and have a small
transformer for each light fitting, or you can use a bigger one that can
run several lights at once. Note however you are better off keeping the
12V cables short, and they will often need to be quite heavy wire to
cope with the extra current (if you keep the power the same, but reduce
the voltage the current must go up to compensate).

So on the face of it you may think mains downlights are simpler since
they are easy to fit, however they are the inferior solution in many ways:

12V will give you more light for the same power, a whiter more natural
light, longer lasting, cheaper, and more robust bulbs, and the option of
using dichroic bulbs[1].


[1] dichroic bulbs have a semi silvered reflector built in, that allows
some of the infrared energy to pass through the reflector and out of the
back of the bulb. This means they give a better colour of light and
throw far less heat forward to whatever they are illuminating (although
the fitting itself will run hotter).

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/