When checking the Screwfix catalogue for something else, I noticed they did 5ft LED tubes for £14.99, claimed to be equivalent to 100W and decided to try one.
They come with a 'special' started (a fuse it seems) and you can then just fit without any rewiring. (I may remove the ballast later.)
Having installed it, it looks good- as bright as the two existing tubes.
Plan is to replace the rest (2 more in garage and 2 in workshop) when I next visit Screwfix.
Wouldn't it be wise to wait a bit and see if these suffer the same uncharacteristically short life as your conventional tubes (as I believe that was why you were looking for an alternative)?
Cheers, T i m
I suspect the problem is that the fittings are old, T12, types and I'm using T8 tubes- ARW's post provided the clue. Some other tubes, used in a suspended ceiling, haven't given any trouble in 20 years (since we bought the house). They've just been removed (part of a bathroom replacement) and are the larger diameter, T12, style.
We have CFLs in several other places and they've been fine.
I think the 'special' starter switch is just a dummy starter with no innards. They're intended to remove the temptation to fill the otherwise empty hole with an actual starter switch.
IIRC, the later T12 in the 5 foot size had a rating of 65W whilst their T8 successors (which can work with a cheap ballasted with starter switch fitting) were rated at 58W. I think the original 1940s lamps had an 80W rating.
A LED replacement tube won't suffer the T8 tubes' fate.
JOOI, did those tubes you've just decommissioned after 20 years of faultless service, happen to light up with no flicker within a quarter of a second of being switched on?
I thought someone (here) said that some of these newer (T8) tubes were designed to work (safely) in the older fittings designed for T12 tubes (or somesuch)?
Cheers, T i m
they were, that was a big part of the whole point of T8s, they were intende d to be a drop-in replacement. I don't believe T8s in a T12 fixture should be a problem.
And even if (theoretically, they don't IRL) 58w tubes were ran at 65w it wo uldn't cause significant loss of life expectancy. You have to deviate by 20 % before significant life shortening is seen.
NT
No, they didn't fail but where 'slow' sometimes with a flicker when starting.
They had conventional starters. I have replaced a couple of the starters in the garage with 'electronic' ones. I can't say I've noticed any real difference. I put the new LED tube in the remaining garage fitting with an old starter.
I've not been impressed by LED lamps in the house until recently. The new bathroom has LED lights which are good and now this tube. I've a few 'smart' LED bulbs (Philips and Ikea) controlled by Alexa- they aren't bad. Previously I've always been disappointed by the output.
No. It is actually required to avoid rewiring the fitting.
On a fluorescent, voltage is applied to the tube by one pin at each end and the ionised gas conducts along the tube. For starting, each end has a second pin and there is a heater coil between the pair of pins. A starter temporarily shorts the second pins at each end together, completing a circuit (Live - Heater one - Starter - Heater two - Neutral). Once the tube has struck, the starter cuts out and the circuit is broken, leaving only the gas to conduct.
When the tube is replaced by an LED one, the driver is connected between the two pins at one end of the tube. The two pins at the other end are connected together. The dummy starter is just a permanent link. The circuit goes Live - Driver circuit (in one end of tube) - Dummy starter
- Linked pins (in other end of tube) - Neutral.
It simply makes LED tubes a direct replacement for the general public. The alternative is not to use dummy starters and to re-wire the fittings internally.
SteveW
I cannot understand this short life of the old tubes either. One would have to have them on and of tens of times a day to make them fail as was stated. it almost sounds like the fittings have some odd kind of design fault ie not turning off the heaters in a timely fashion or something, often the give away are prematurely black ends in the tube. I cannot think though that such a fault would affect LEDs as there is no starter mechanism involved exterior to the actual tube itself. Brian
The only issues I have had with cfts and leds is the noise they generate in the radio spectrum. Not all do this and I suspect once again its cheap switch mode psus with little interference suppression or good design, ie if it lights and does not go bang then its fine, kind of engineering. Brian
Well I still have three Thorne fittings with the thicker tubes and although these days they are little used for obvious reasons, in the past my main gripe was hum from them when they were on. i guess this would go away if I replaced the tubes with LED ones that fitted the 4ft sockets and took away the starter. Brian
no, you left the humming ballasts in circuit.
NT
ARW suggested that T8 tubes can suffer in T12 fittings. I suspect, the garage fittings may be T12 ones. I assume they were fitted when the house was built (mid 80s). The bathroom which has just bee revamped was original and had large dia tubes above a suspected ceiling. While I never replaced the tubes in the bathroom (at least as far as I recall) in the 21 years we've been here, I've replaced numerous tubes in the garage. Having said that, the bathroom has a window and so the light isn't always used, plus we have another bathroom. The garage lights are possibly used more often as there is no natural light and, besides being a garage, it has a utility area, freezers, and is used as a work shop - besides for a garage.
We have some halogen lights which are also prone to short life. The fittings have two 40W G9 (I think bulbs). I've tried LED versions but the light output is disappointing. We really like the fittings and I'm considering modifying them to take a different bulb. Possibly a 2D LED panel (the fittings are square and look about the right size).
Interesting. I was wondering whether the fittings were using "Quickstart"(tm) ballasts which would have neatly explained their long life. Obviously not. In fact that seems more like the behaviour of my 5 foot T8 tube in my office fitting using a selected starter to get it fire up at all (the Quickstart upgrade had to be downgraded since T8 tubes just sit there like dummies in a QS ballasted fitting).
I've never seen the 5 foot tubes (both T12 and T8) do the classic flash, flash, flashity flash startup sequence of the switch start 4 foot fittings, it just sits there with no indication it's been switched on for
4 to 6 seconds before it springs into life as if nothing was wrong. Since this is rarely cycled on and off more than twice in an evening, it's just not worth fretting over.Those last four words had me confused. I'm guessing you really meant "old fashioned switch start fitting" rather than the implied LED tube and an old starter switch. :-)
Until now, you had justification for not being impressed with *most* LED GLS lamps being foisted on the all too trusting shopper. It's true you could get genuinely "60W (the better American 810lm standard) incandescent equivalent" LEDs which outshone the 20W CFL versions for a mere 12W (claimed - it was more like 14W - still less than the dimmer CFL version) when the 81LPW lamps first started to appear about 5 years ago. This was about the limit until just over a year back when the 125LPW "100W 1500lm equivalent" GLS lamps appeared in Home Bargains stores at £2.99 a pop (still their current price).
The limiting factor regarding the incandescent wattage equivalency is the much lower maximum temperature limit of the lamp (circa 80 deg C versus the 200 or degrees of a classic tungsten filament lamp). The better the LPW performance, the more light you can get for your watt and the less of that energy input is turned into heat.
People had overheating issues trying to use the brightest available LED lamps of the day if they overlooked the ventilation requirements in fittings that restricted the free flow of air which wasn't an issue with incandescents which could compensate by running 10 to 20 degrees hotter, not something you could do with an LED which may already have been within
5 degrees of its limiting maximum temperature in a freely ventilated fitting to begin with.As LED lamp technology improvements approach the 303LPW figure reached in Cree's Labs just over four years ago, this overheating will become less of an issue and the lamps more likely to meet their promised 20 to
30 thousand hour lifetime ratings.
I've got a twin 6ft fitting in the cellar. One tube is the original basic white T12 and the other a replacement T8 basic white from TLC. The T8 comes on some time after the T12 - and never looks as bright, despite being shed loads newer. It does eventually get a bit brighter than at first, though.
(at one time I used the cellar as a workshop, but is now just storage, so haven't bothered sorting things.)
Yes, it could have been more clear. Try: I put the new tube in the fitting which still had an old style starter in it, which I replaced with the special (dummy) one supplied.
I had noticed the ones with electronic starters seemed to last longer.
(I'm not sure why I didn't replace all the starters. I suspect the supplier didn't have stock at the time and I didn't get around to it.)
They are shorting links and may use a fuse so they blow if you put a normal tube in.
The normal replacement tube has mains in on the two pins at one end. The other end has two pins shorted together.
The result is
live in > ballast ballast > one pin at end the other pin > starter the starter > one pin at other end other pin > neutral
Thus the tube gets L&N whichever way around it is. There is some drop in the choke but not enough to stop the tube working.
The choke was falling to bits in the last one I did so I removed everything and its just L&N to one end but it will only work one way around.
Its labelled so its OK for anyone that can read and the fuse and probably the heater will blow if someone puts a normal tube in.
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