Hi

I'm thinking of installing some in the upstairs bathroom; which is
plasterboard with a thick layer of Rockwool on top.

I know from experience how much heat is chucked out from the
downlighters fitted in my kitched ceiling. So what's the correct
procedure for an upstairs ceiling? I'm sure there would be a fire
risk if I just left the layer of insulation untouched; yet to cut a
large circular hole in it around the light fitting would I'm sure be
very wasteful of heat when the lights are off.

I'm envisaging maybe I need to nail a plasterboard 'bridge' spanning
the joists adjacent to each light, and then running the Rockwool over
that, thereby leaving an airgap above the fitting. Is that
appropriate /OTT /inadequate?

Thanks
David

Its suggested by the manufactures to cut a circle of rockwool around the
downlighters. As for the heat loss I think it will be negligible unless you
are planning on installing hundreds of them, Also the back of the lights is
I think meant to be clear for about 10-20 cm

In article , Lobster
writes
Hi

I'm thinking of installing some in the upstairs bathroom; which is
plasterboard with a thick layer of Rockwool on top.

I know from experience how much heat is chucked out from the
downlighters fitted in my kitched ceiling. So what's the correct
procedure for an upstairs ceiling? I'm sure there would be a fire
risk if I just left the layer of insulation untouched; yet to cut a
large circular hole in it around the light fitting would I'm sure be
very wasteful of heat when the lights are off.

I'm envisaging maybe I need to nail a plasterboard 'bridge' spanning
the joists adjacent to each light, and then running the Rockwool over
that, thereby leaving an airgap above the fitting. Is that
appropriate /OTT /inadequate?

Other posters to this group have previously suggested putting terracotta
plantpots over the light fittings, & cut the rockwool to fit round the
plantpot.
--
Tim Mitchell

"The Question Asker" wrote in message ...
Its suggested by the manufactures to cut a circle of rockwool around the
downlighters. As for the heat loss I think it will be negligible unless you
are planning on installing hundreds of them, Also the back of the lights is
I think meant to be clear for about 10-20 cm

You need to construct a small box with air holes to fit over the back
of the fitment because in the future someone might otherwise disturb
the rockwool and thus cause a fire hazard.

On Fri, 23 Jan 2004 11:27:09 +0000, Tim Mitchell
wrote:

Other posters to this group have previously suggested putting terracotta
plantpots over the light fittings, & cut the rockwool to fit round the
plantpot.

TLC Direct sell commercial downlighter covers which appear to have
these sorts of characteristics:

http://tinyurl.com/34r6g

PoP

Sending email to my published email address isn't
guaranteed to reach me.

In article , Jack the
Lad writes
"The Question Asker" wrote in message
...
Its suggested by the manufactures to cut a circle of rockwool around the
downlighters. As for the heat loss I think it will be negligible unless you
are planning on installing hundreds of them, Also the back of the lights is
I think meant to be clear for about 10-20 cm

You need to construct a small box with air holes to fit over the back
of the fitment because in the future someone might otherwise disturb
the rockwool and thus cause a fire hazard.

Why the airholes? and what's wrong with an upturned clay flower pot?
--
David

TLC Direct sell commercial downlighter covers which appear to have
these sorts of characteristics:

http://tinyurl.com/34r6g


Bit more expensive than a flowerpot! But then they are designed to restore
ceiling fire resistance for commercial use; I'd think they were OTT for
domestic

wrote:

In article , Jack the
Lad writes

"The Question Asker" wrote in message
...

Its suggested by the manufactures to cut a circle of rockwool around the
downlighters. As for the heat loss I think it will be negligible unless you
are planning on installing hundreds of them, Also the back of the lights is
I think meant to be clear for about 10-20 cm

You need to construct a small box with air holes to fit over the back
of the fitment because in the future someone might otherwise disturb
the rockwool and thus cause a fire hazard.


Why the airholes? and what's wrong with an upturned clay flower pot?


You have to get rid of the heat somehow to avoid the cavity getting hot
enough to melt wiring insulation.

Heat will be lost via the plasterboard into the room, and upwards
through the flowerpot base - holes in it help if teh pot top pokes
through the insulation.

Experience shows a simple void of a sqaure foot or so is enough to leak
heat down through the plasterboard, but rockwool wrapped transformers
will fail :-)

In article , The Natural Philosopher
writes
wrote:


Why the airholes? and what's wrong with an upturned clay flower pot?


You have to get rid of the heat somehow to avoid the cavity getting hot
enough to melt wiring insulation.

Heat will be lost via the plasterboard into the room, and upwards
through the flowerpot base - holes in it help if teh pot top pokes
through the insulation.

Experience shows a simple void of a sqaure foot or so is enough to leak
heat down through the plasterboard, but rockwool wrapped transformers
will fail :-)

The type that I have use a heat resistant cable closest to the lamp and
the transformer is outside of the flowerpot with the cable going through
the hole in the bottom of the pot (which is now the top IYSWIM)
I have felt the pots a number of times and whilst it is warm I wouldn't
call it hot.
The only one that I have where I have thought about heat dissipation is
the shower one which has a sealed lens but this is no hotter than the
others.
--
David

Tim Mitchell wrote in message news: Other posters to this group have previously suggested putting terracotta
plantpots over the light fittings, & cut the rockwool to fit round the
plantpot.

That's what I did a little under two years ago and all seems to be
running fine. If I remember correctly the flowerpots were about 12"
diameter and 6" deep. Rather confused the assistant in the local
garden center though:

Assistant: Do you need any help?
Me: No, not really. Just trying to decide what size I need.
Assistant: What are you going to be putting in them?
Me: Bulbs.
Assistant: What type of bulbs?
Me: 35W Halogen.

I replaced the fibre glass around the upturned pot. From what I
remember the electronic transformer is under the fibre glass and I
haven't had any problems.

Andrew

On 26 Jan 2004 09:38:50 -0800, (Andrew May)
wrote:

Tim Mitchell wrote in message news: Other posters to this group have previously suggested putting terracotta
plantpots over the light fittings, & cut the rockwool to fit round the
plantpot.

That's what I did a little under two years ago and all seems to be
running fine. If I remember correctly the flowerpots were about 12"
diameter and 6" deep. Rather confused the assistant in the local
garden center though:

Assistant: Do you need any help?
Me: No, not really. Just trying to decide what size I need.
Assistant: What are you going to be putting in them?
Me: Bulbs.
Assistant: What type of bulbs?
Me: 35W Halogen.

I replaced the fibre glass around the upturned pot. From what I
remember the electronic transformer is under the fibre glass and I
haven't had any problems.

Although they might not fail immediately they will fail prematurely.
Also depends whether the transformers have self diagnostic circuits in
or just bog standard cheapy ones.


SJW
A.C.S. Ltd.

"Jack the Lad" wrote in message
m...
"The Question Asker" wrote in message
...
Its suggested by the manufactures to cut a circle of rockwool around the
downlighters. As for the heat loss I think it will be negligible unless
you
are planning on installing hundreds of them, Also the back of the lights
is
I think meant to be clear for about 10-20 cm

You need to construct a small box with air holes to fit over the back
of the fitment because in the future someone might otherwise disturb
the rockwool and thus cause a fire hazard.

Best install a plantpot over and seal with silicon sealing. A decent sized
one will do, with a bit of air in there.

"The Question Asker" wrote in message
...

Its suggested by the manufactures to cut a circle of rockwool around the
downlighters. As for the heat loss I think it will be negligible

The heat loss is highly significant.

hi guys...

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

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

any help would be great

Craig

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 |
\================================================= ================/

cjbeattie wrote:

Oh, forgot to say

and where would i purchase one from?

http://www.tlc-direct.co.uk/Main_Ind...ers/index.html

http://www.screwfix.com/app/sfd/cat/...8061&id=101667

--
Cheers,

John.

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

ok john

thanks for the tips....

i understand a wee bit better now...

i bascially inherited the house from my mam & dad who passed away last year and suffice to say nothing has been done for around 10 years....

im very very new to diy hence the statement (go easy)

I bought the downlighters from wickes... and i think from you have said that they are indeed the ones you can wire into the mains... so this i will do...

I was thinking of using the original ceailing output... which i will plaster over when finished and then splitting the wires into 4 ways (via a junction terminal) and then changing the bulbs from 50w down to 20w (ive read quite a bit on heat etc from 50w bulbs) anyways this will keep within the 100w i presume that the hall light had in the first place....the cavity between the floors... where the lights will be is quite small its a prewar (ex council house) and hence the old design.. the gap is only around half a foot... still enough i hope for the downlighters because ive bought the bloody things now lol...

anyways the lights i have like i said are from wickes and on the box it says...

WICKES
4 Mains Halogen Round fixed downlights

i presume (and hope) these ones will be ok to wire direct.... i will also use the plant pot idea for the heat dispersion of the untils when under the floor boards.... i assume they mean REAL CLAY plant pots yes? as plastic would melt...

you said "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."

forgive me for being ignorant but what is a junction box exactly? (is it a terminal block connector? will that suffice? and what is a star wiring or daisy chain wiring? thanks... i think i will go down the mains wiring option



anyways thanks for the help john (probaly saved me from burning my house down lol)

Craig

ps....if you have msn messenger then please feel free to add me.. mine is ***Katncraig86 (AT) hotmail.com********

then i will have a online guro if i need one

once again thanks

cjbeattie wrote:

I was thinking of using the original ceailing output... which i will
plaster over when finished and then splitting the wires into 4 ways
(via a junction terminal) and then changing the bulbs from 50w down to
20w (ive read quite a bit on heat etc from 50w bulbs) anyways this will
keep within the 100w i presume that the hall light had in the first
place....the cavity between the floors... where the lights will be is
quite small its a prewar (ex council house) and hence the old design..
the gap is only around half a foot... still enough i hope for the
downlighters because ive bought the bloody things now lol...

Yup that ought to be OK. A couple of things to check though.

Firstly most mains downlighters are metal bodied and hence must be
connected to an earthed lighting circuit. There is a small possibility
if the house wiring is very old that it is not earthed. Looking at the
cables will tell you. Modern cable will have two insulated wires in it
(typically red and black in your case) plus a third bare wire.

If you are missing the earth wire then *do not* inttall the downlighters
unless they are marked as "double isolated" (the double isolated logo is
two small concentric square boxes).

anyways the lights i have like i said are from wickes and on the box it
says...

WICKES
4 Mains Halogen Round fixed downlights

OK they probably take bulbs of type GU10 then. These are ok for direct
connection to the mains. You will get to know that bulb number well! ;-)

i presume (and hope) these ones will be ok to wire direct.... i will
also use the plant pot idea for the heat dispersion of the untils when
under the floor boards.... i assume they mean REAL CLAY plant pots yes?
as plastic would melt...

Yup, your traditional clay/terracotta jobbie.

you said "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."

forgive me for being ignorant but what is a junction box exactly? (is

It looks like this: (also available in brown)

http://www.screwfix.com/app/sfd/cat/...18802&ts=63625

Note this is a four terminal box[2]

it a terminal block connector? will that suffice? and what is a star
wiring or daisy chain wiring? thanks... i think i will go down the
mains wiring option

Star wiring is where you run a separate wire from the junction box to
each light. So if you have four lights there are four wires coming from
the junction box - one to each light.

Daisy chain is where you run from the JB to the first light, and thence
the second and third and fourth. You could also use some combination of
the two if required[1].

anyways thanks for the help john (probaly saved me from burning my
house down lol)

Hopefully it is fused or has a micro circuit breaker somewhere which
ought to stop that happening!

ps....if you have msn messenger then please feel free to add me.. mine
is ***Katncraig86 (AT) hotmail.com********

then i will have a online guro if i need one

If you post here there you will usually get a quick answer since there
are plenty of folks in this newsgroup well able to answer these sorts of
questions.


[1] Running wires in ceilings is easy if they run in the same direction
as the joists - you can do it all from the ceiling side. If however you
need to run across the joists then you need to lift floorboards in the
room above so that you can drill holes through the middle of the joists
for the wires (don't put holes near the top or bottom of the joist since
that not only weakens the joist but also makes the cable vulnerable to
damage from nails and screws etc). Hence it is often easier to use a
combination of star and daisy chain wiring to minimise the difficult
cable runs across the joists. e.g.

Original Room/light position


=====================================
| |
| |
|-----------------------------------| --- joists
| |
| |
|-----------------------------------|
| L |
| |
|-----------------------------------|
| |
| |
=====================================

New lighting using a mixture of star and daisy chain wiring:

=====================================
| |
| L1----------------------L2 |
|-----------------------------|-----| --- joists
| | |
| | |
|-----------------------------|-----|
| ------------JB----------+ | - two cables leave JB
| | |
|-----|-----------------------------|
| L3----------------------L4 | - cable daisy chained
| |
=====================================

[4] Most lighting wiring is wired using the "loop in" method. That will
mean that when you look at a ceiling rose you may be surprised how many
wires there are! There will be a cable bringing power (comes from the
previous light in the circuit), and another taking it out again (to the
next light), plus one more to the switch. This gives you nine individual
wires to play with and another two connecting to the light pendant. You
will need to transfer these to a junction box and wire the new lights
such that they are connected where the pendant is currently connected.


--
Cheers,

John.

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

cjbeattie wrote:

ok i will do exactly that what you suggested... and yes the lights have
double sign thingy you mentioned so dont worry about earth...

Well if it is there, wire it up correctly as you go. When you get to a
light fitting that does not require it, just slip some green yellow
sleaving over it and fold it back rather than cutting it off - you never
know when someone will change a fitting in the future adn find they need
it.

after thought i realised my hallway is quite big really and since im
downgrading the lights all down to 20w..

would it be ok to run 6 in total off the original lighting source?
instead of 4.. like i said the post before...

As long as you don't exceed the rating of the circuit you are fine. Most
lighting circuits are protected by a 6A MCB these days which gives you
at least 1380W to play with. Go round and count up how much is already
on the circuit. For every light position that is less than 100W, count
it as 100W, for any that are more count them as their actual value.

i said i was downsizing all the bulbs to 20... MUST i do this? or will
the system still take 6 - 50w downlighters? As you can probaly tell im

6 x 50 = 300W probably fine unless the circuit is allready highly loaded.

a complete noob to electrics... hence what are to you probaly stupid
questions... we all goto learn somewhere i guess...

The only stupid question is the one you don't ask, as they say!

--
Cheers,

John.

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

hi john

thanks for the prompt reply

ok i will do exactly that what you suggested... and yes the lights have double sign thingy you mentioned so dont worry about earth...

i was wondering though..

after thought i realised my hallway is quite big really and since im downgrading the lights all down to 20w..

would it be ok to run 6 in total off the original lighting source? instead of 4.. like i said the post before...

i said i was downsizing all the bulbs to 20... MUST i do this? or will the system still take 6 - 50w downlighters? As you can probaly tell im a complete noob to electrics... hence what are to you probaly stupid questions... we all goto learn somewhere i guess...

anyways...if you could answer the above posts that would be great

thanks for all your help....

Craig