I am planning to fit about 6 12v ceiling spot lights in an apartment
living room. There's an existing ceiling rose, that I'll be getting rid
of, and as such I plan to wire the transformer to the supply to the
existing light. My only concern is running the cables to the spotlights. I
expect there will be joists in the way, and I don't know if there will be
any space between the top of the joists and the floor of the next
apartment. It's an old custom built block, about 20 years old.
I had read about people having to cut out portions of plaster board around
joists to then cut a hole in a joist.
Is this difficult?
How would I patch up the hole again, so that it would not be noticible
Any suggestions would be very welcome.
To avoid replacing bulbs on a weekly basis, look at the LV versions.
I have been in this house now for two years since first lighhts went on.
In that time I have replaced COUNTLESS mains bulbs, but the only LV bulbs that
after a couole of years of CONTINUOUS DAILY USE of at least 4 hours per
day, are the half ones that came with a couple of rail units.
I got about 50 LV 50W lamps from Newey and Eyre, AND NONE HAVE GONE IN
TWO YEARS. They are used in all the corridoors and bathrooms and the
kitchen, so they are not just 'occasional use'..
Friends who have mains units on average seem to have one a week going in
winter - about 5% failure. That implies the average weekly life is no
more than 20 weeks of heavy duty.
I seem to be getting better than 200 weeks average. My bulbs cost about
2 quid each. The mains are a bit cheaper, but overall the savings are
there on LV.
I had one supposedly thermally protected toroidal transformer go after a
few weeks. None of the electronic transformers have gone.
Well I don't know what service life is, but nearly all of my 40W candle
bulbs have been replaced in that period. Say 90% The cheapo LV ones have
had 50% failing two years. The Newey ones have not failed at all. All
the 60W standard bayonets have gone in the two years. So it would seem
that the average life of a mains incandescent bulb is a tad less than a
year under heavy use, but the better LV spots are looking more like
three years, with a mean life of 2 years on cheapo LV. It MAY be that
the cheapo ones are on electronic transformers, that came with them, of
a higher voltage output than my normal Newey toroids. With which the non
dimmed units are equipped.
Ah - say no more. Candle lamps seen to go straight out of the box,
My RO80 types of which I've many seem to have the same sort of life as a
gls, and I've not had LV types for long enough to form an opinion. But
they are looking good. I'd happily replace all the RO 80 ones with LV, but
of course I'd like the smaller fittings too, and that means replacing
plaster, etc. I've also got several PAR 38 fittings, and some of those
have 25 year old bulbs...
*Time is fun when you're having flies... Kermit
Dave Plowman firstname.lastname@example.org London SW 12
I've got some 40W screw-in spots in a 4-way cluster in the kitchen, the kind
with the screw diameter about half that of an "average" bulb. I think the
best record for any bulb's life is six months, and it is pretty much
guaranteed that at least one is out at any time. I tried switching to a
dimmer thinking that lowering the light level might extend life, but no joy.
Yet, in the lounge, from the same supply (and fuse), is a 5-way cluster of
40W candle bulbs that haven't blown ever in the three years I've lived here.
Usage is pretty much the same for both rooms. From the same double dimmer
switch are another two candle bulbs on the wall that have average lives. I'm
thinking about submitting the ceiling ones to medical science due to their
longevity. Not as good as this one though:
Any ideas on the kitchen ones? It's bankrupting me, and it's also a PITA
replacing them due to their height/location. Other bulbs in the flat seem
Do the maths on how long the cluster will have been on in those 6
months. 5 1/2hrs day = 1000hrs about normal bulb life...
Why do these fail rather than the candles? Probably excessive heat
build up in the fitting. I expect they are fairly well enclosed in
plastic around the back of the bulb.
Do you run them dimmed though? Another cause of bulb failure is
vibration, is there any visible shaking of the filament (watch one of
the light patches) when someone moves about in the rooom above, bear
in mind children are very heavy footed. B-)
Don't buy your bulbs from a DIY store or supermarket. Find an
electrical wholesaler and buy 10 or so at a time at roughly 50% the
Dave. pam is missing e-mail
True, but the rate of failure is at least double all of the others in the
norm suggested that as well. I'm not too sure in this case, having just
taken a look. The glass part of the bulbs are entirely open to air, with
only the screw having a plastic surround, and this isn't especially tight
either. There is a 2mm thick piece of donut-shaped decorative plastic that
sits around the bulb at it's widest point like a halo, but I make sure that
it's never touching the bulb. The support legs for it are also quite thin.
Plenty of ventilation. Would ambient room temperature be a factor? The combi
boiler is in the kitchen and the thermostat isn't...usually nice and toasty
Yeah, I run them dimmed mostly at night....mostly. Except for just now where
only two of them are working!!
No shaking (or noise) from above either, big old sturdy building with
elderly people above me.
I'm starting to get the opinion these bulbs just suck!
Mailing bulbs through the post? ;-) Interesting...will look into the prices
Does anyone have any preferences for bulb manufacturer? Do some last longer
Maybe they are on twice as long? I fitted a PIR to the kitchen light
in my old flat 'cause I was for ever leaving it on (3 x 60W spots).
I recognise the style. Shouldn't think heat is the problem, how hot
does the plastic shroud to the base get after a few hours?
The other thing is vibration. You might not hear the the noise, you
need to watch the intensity/position of the light patches to see if
there is any shake there. A tiny movement in the filament shows quite
dramtically in the light patch.
No, most towns have at least one wholesaler, might have a "Trade Only"
notice but business is business buy a reasonable quantity with cash
and I doubt they'll refuse you.
Not that I have noticed. I have a sneaky feeling that GEC and Osram
all come out of the Ring factory in Leeds. I don't have a particulary
high opinion of Ring...
Dave. pam is missing e-mail
On Mon, 08 Dec 2003 10:49:28 +0000 (GMT), "Dave Liquorice"
That's just a depot, (it's about a mile away from here) there is a
"Factory" shop on site there.
Osram is the 2nd biggest manufacturer of lamps in the world based in
Germany, their lamps were sold here under the Wotan brand. Oddly at
the same time G.E.C. was making lamps and selling them under the Osram
brand, probably all due to reparations after WW1. Recently G.E.C.
lamps merged with Osram.
It's just an importer of cheap bulbs sourced from anywhere at all.
Some 40w golf ball bulbs I bought there recently lasted less than 1
week! If anybody has any suggestions for a long life substitute for
these I'd be very greatful, my ceiling fans take 2 of them (ES
fitting) and candle lamps won't fit (too long).
Osram had a factory in Hammersmith but during WW1 this was taken
over by GEC. Previously all their R&D work had been done in
Germany. Clifford Patterson, who was at the time church
secretary at my church and a lighting expert at the nearby NPL
in Teddington was head-hunted to set up an R&D facility for GEC
which he did, initially in Hammersmith, moving to purpose built
labs in Wembley in the early 1920's. This work developed into
research into valves, radio and radar, also the first
fluorescent lamps. See the last few paras of
http://www.sda.co.uk/twickurc/whoswho.htm on our church history
pages for further reading.
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser
Osram was part of GEC (called GEC Osram) when I started working
for GEC in 1983, and the lamps were available through the staff
discount scheme. A few years later, GEC sold Osram (to Siemens at
the time I thought, but certainly a German company).
I've got a couple of Ring 500W halogen lamps, which completely
silvered over after a few hours use (not on a dimmer). I think
they forgot to put any gas in the quartz tube.
Actually, nothing to do with that. I worked for GEC Computers
I have always been interested in lighting, and made various
discharge lamps and control gear for standard discharge lamps
when I was at school. Don Klipstein seems to have saved something
I wrote about making my own fluorescent dimming ballasts here:
Reading Borough Council (as then was) were happy to give me a
number of decommissioned streetlamps of different types, still
working, which I experimented with. I've maintained the interest
in lighting always, and kept reasonably up to date with what's
going on in the industry.
I could believe that.
Another excellent UK company in this area was Thorn Lighting.
They got taken over by EMI, probably sometime in the 1980's,
and my perception was they lost their edge. Finally, there
was a management buyout, but to finance this, they had to sell
the lamp manufacturing to GE in the US (nothing to do with GEC
in the UK), and Thorn Lighting only retained the luminare/lantern
part of the former company. In addition to the lamps themselves,
they had previously manufactured control gear too -- I don't know
what happened to that part of the business.
Mazda (god of light) was one of the Thorn lighting lamp brands,
now used by GE. (Actually, I think GE always had rights to the
Mazda name in the US, even before it bought that part of Thorn
Those screw in bulbs are the work of the devil. I'm always replacing
them at my mother in laws flat. I suspect the failure rate has as much
to do with the fitting as anything else. I believe that ventilation is
important to reduce the effects of thermal cyling on the bit of the
bulb where the glass is sealed / joins the metal bit. If the thing
gets too hot repeatedly the seal goes, air gets in and kappow !
I'd be looking to replace the whole fitting and go for a different
type of bulb. They're crap. And not cheap crap either.
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