I guess it makes economic sense to do so now that the tube has blown.
I have partially dismantled the existing fitting.
Do these things have standard mounting holes so that a new batten
fitting would slot into place?
The old one probably dates back a few decades.
Also, why on earth are there no less than four twin-core and
earth cables coming out of the ceiling?
(All the cores are wired together in terminal blocks wrapped
in tape. Looks like a bit of a bodge job).
Usually. Some are designed as straight drop in replacements. Others will
require some wiring changes to the fitting to take the old magnetic
ballast out of circuit. Follow the instructions with your lamp carefully.
You would normally expect at least 3, however it may be you have a
branch in the circuit at that point, with a feed to an additional lamp
being taken from the position.
See here for an illustration:
(you may have more than one "Supply cable to next light fitting")
ah, ok misread that. That should be easy enough, but the screw holes etc
are less likely to match!
The cable out is not necessarily to an additional lamp on the same
switch (although that is a possibility), but is usually the power feed
to the next lamp - which will probably be in a different room. (i.e. the
circuit starts at the consumer unit and runs to the first lamp, then
daisy chains to the next one in the next room. The last lamp fitting on
the circuit will not have a feed out - so there would usually just be
two cables on that - power in and a drop to the switch).
Ah, gotcha, although in this case I'd expect it to go on to the other
light fitting in the kitchen - no sign of a branch, but there may
have been one originally. But four is only one more than "normal"
so I can rest easy.
It doesn't *have* to daisy-chain, lighting circuits are radial circuits
so branching is perfectly valid. In that case, one cable will be the
switch drop, one will carry unswitched power from the previous light or
the consumer unit, and the other two will carry unswitched power to two
other light fittings - either or both of which may have more fittings
On Fri, 1 Dec 2017 10:20:03 -0000 (UTC), "Fevric J. Glandules"
There's no guarantee that a new fitting will use the same mounting
holes as the existing. I think that's what you mean.
If you just replace the tube you will have to remove the starter
(Little thing that sticks out at the side. Just twist it to remove.)
from the fitting. Some LED tubes require a dummy starter but that
should be supplied if required.
But does it? Fluorescents are vastly more efficient than tungsten. And
have a longer life too. So any savings in running costs not the same sort
of percentage. You'd need to do careful sums, given LEDs cost more.
*Never slap a man who's chewing tobacco *
Dave Plowman firstname.lastname@example.org London SW
I have two Thorne fittings here one double one single unit and was
wondering the same. Both have now started to buzz, one assumes from the
ballast choke. Not having had experience of replacing with led, does one
just take the capacitor, choke and starter out and wire up one pin or
both to the mains input or what? I'd be loathe to remove the fittings as the
next thing will be the ceiling will need to be redone with paint!
This newsgroup posting comes to you directly from...
On Friday, 1 December 2017 17:15:00 UTC, Brian Gaff wrote:
Sometimes buzz is caused by a bad tube partly rectifying the power. If the cause is the ballast, take hammer & nail to the edges of the ballast laminations, or varnish it. In the unlikely event those fail, mount the ballast on rubber washers.
On Fri, 01 Dec 2017 15:08:42 +0000 (GMT), Dave Plowman (News) wrote:
That depends, Aldi were flogging off 5' 20 W 2000 lm LED "tubes" for
£4.99... Roughly half the lumens of a 5' 58 W florry but as our eyes
are log not lin the reduced level isn't really noticeable. Put it
this way there has been no adverse comment from SWMBO'd, mind you I'm
not sure she has noticed the instant start rather than the several
second preheat of the traditional florry.
These LED tubes are direct replacement for a florry tube and are
supplied with a dummy starter. I suspect that leaving a standard
starter in would kill the tube when it tries to strike it...
Not actually sure why they need a dummy starter. Is it just to get
power to one end of the tube for the LED driver?
Well half the lumens are not going upwards and getting wasted!
The dummy starter is to get L&N at one end, well actually either end, so
that the LED tube can be fitted either way around and still work (one
end of the LED tube is a short).
Leaving in the original starter will not kill the LED.
But is a lot easier for those that buy them in the
shop and just plug them in to the existing batten.
And a lot safer when someone else replaces the led
tube with a traditional fluoro tube when the led tube
fails and they know so little about what they are
doing that they don’t even realise it’s a led tube.
As the most common LED tube sold in the UK is shorted at one end and has
the driver at the other end then it makes sense to wire the fitting to
suit that and make sure that the lamp will work either way around
without causing the MCB to go bang.
In our old house I fitted electronic starters 20 odd years
ago. Virtually instant start with no noticeable delay and no
Damn! Should have rescued them before we moved! On the other
hand, if I replace them with LEDs when the current tubes
die, I won't need them, will I?
On Sun, 3 Dec 2017 18:50:51 -0000, Terry Casey wrote:
Electronic starter or electronic ballast? Our florries have lumps of
iron ballasts but electronic starters, they have a good second or two
preheat before striking, first time, everytime. Electronic ballast
for the fish tank lights also delays before striking. I was under the
impression that striking a florry before the filaments were hot
wasn't a Good Idea, mind you they probably get hot enough within 1/2
On Mon, 04 Dec 2017 09:33:50 +0000, Dave Liquorice wrote:
The half century old "Quickstart"(tm) transformers certainly managed to
start up in something like 250 to 330ms (about as quick as the four
12v35W halogen downlighters in the shower room, each fed from their own
individual "electronic" transformer) and the tubes would last many years
in the kitchen fitting.
Unfortunately, the days are numbered for the one remaining 40W 4 foot
"Quickstart"(tm) fitting in the basement (and the other 7or 8 spares in
the attic) since *suitable* T12 tubes have become as rare as rocking
horse shit. In any case, whilst producing plenty of light, their 51 watts
of total energy consumption versus the 36 watts of a modern
electronically ballasted T8 tube is incentive enough to "upgrade" from a
"Quickstart"(tm) ballasted fitting.
The "cheap" B&Q electronically ballasted 4 ft slimline fitting we bought
two or three years ago to replace the "Quickstart"tm) kitchen fitting
instantly started the T8 tubes but the Chinese ballast housed inside of a
rectangular plastic tubing proved a bit rough on tube life (the first,
supplied, tube expiring in less than a year with a quality tube lasting
little more than 12 months). The last tube, after turning it end over end
in the fitting to get a few more hours of life, eventually caused the
ballast to literally go "Phut", necessitating a replacement ballast *and*
tube to effect a repair.
I managed to locate a Helvar ballast on Amazon for less than a fiver
delivered. This was about the same physical size but in heat dissipative
metal and didn't route the pvc insulated tube connection wiring
internally against the heatsink tabs of the power transistors like the
Chinese ballast had done (the most likely cause of the failure as the
insulation had melted, shorting the conductor to the power transistor
Also, the Helvar unit had published specifications on max ambient
temperature and hour lifetime ratings and (missing from the Chinese unit)
microprocessor control which stopped it trying to run both failed tubes
(hence the purchase of a replacement tube I had hoped might not have been
The Helvar unit doesn't attempt instant start, taking a good 900 to
1000ms of pre-heating to strike the tube from switch on (the Chinese
ballast took about 300ms of flickery (25 to 50Hz) ignition attempts
before lighting up to full luminance unlike the "Quickstart"(tm)
transformer which applied some 250 to 300ms of preheat before springing
into full luminance sans flicker).
I do miss the startup characteristics of a "Quickstart"(tm) ballasted
fitting which doesn't compromise tube life. The full one second's worth
of pre-heat used by the "modern" electronic ballast strikes me as being
needlessly protective of tube life imo (and, therefore, an irritating
reminder of just what has been lost to the Gods of efficiency and
microprocessor technology "advances").
I did briefly consider the expensive "LED Tube" fitting option until I
saw just how low their lumens output was and how directed it would have
been onto the kitchen floor and away from the ceiling and worktops.
Unless a LED based lighting manufacturer considers the need to use the
full 360 of the tube's circumference as a light emission surface for
domestic kitchen lighting duty at better than 100 LPW, I'll be using a
fluorescent tube based kitchen lighting solution for the foreseeable
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