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How to fit a normal bulb in a BC3 fitting and save £10 per bulb

BC3 and 2-pin bayonet fitting compared
Standard 2-pin bayonet cap (left) and 3-pin bayonet cap BC3 (right) fittings compared

Summary for mystified international readers: In the UK new houses/flats must, by law, have a number of light fittings which will ‘not accept incandescent filament bulbs’ (a ‘green’ idea). This has led to the development of a proprietary, arbitrary format of compact fluorescent bulb, the BC3, which costs a lot more than standard compact fluorescents, is difficult to obtain, and about which the public generally doesn’t know much (yet). If you’re so minded, it’s not hard to modify the fitting and save money.

A lot of visitors have found this blog recently via searching for information on the MEM BC3 3-pin bayonet compact fluorescent bulbs, where to get them, and why they’re so expensive. The main posts here discussing them, with background to what it’s all about, are A bright idea? and some more thoughts – and it’s readers’ comments which are the really interesting part of both posts.

There are so many stories of frustration there, of people trying to ‘do their bit’ for the environment, trying to fit better CFLs in their homes, and finding that instead of instead of the subsidised or even free standard 2-pin bayonet CFLs available all over the place in a variety of improved designs, styles and quality, they’re locked in to having to pay 10 or 15 times as much for a BC3 bulb, and order online, simply because the manufacturer has a monopoly, and does not seem to supply the bulbs to normal DIY or hardware stores.

Frankly, the system is appalling, an example of exactly how not to design for sustainable behaviour. It’s a great ‘format lock-in’ case study for my research, but a pretty pathetic attempt to ‘design out’ the ‘risk’ of the public retro-fitting incandescent bulbs in new homes. This is the heavy-handed side of the legislation-ecodesign nexus, and it’s clearly not the way forward. Trust the UK to have pushed ahead with it without any thought of user experience.

One of the most egregious aspects for me is the way that Eaton’s MEMLITE BC3 promotional material presents users with, effectively, a false dichotomy between the ‘energy saving BC3’ and the energy-hungry GLS incandescent filament tungsten bulbs, as if these are the only two options available. There is no mention at all of standard 2-pin bayonet CFLs which have all the advantages of the BC3 with none of the disadvantages. The adoption of CFLs has been, I would argue, in large part because they are widely available as drop-in replacements for standard 2-pin bayonet (or Edison screw) bulbs. If they’d all required special fittings, very few people would have bought them.

Anyway, if you don’t fancy swapping your BC3 fittings for standard 2-pin bayonet ones (which is cheap but would(?) presumably make your home non-compliant with part L of the building regulations – any knowledgeable readers able to clarify this?), it isn’t actually too difficult to get a 2-pin bulb to fit acceptably. You will need a pair of pliers, ideally thinner/longer-nosed than the ones in my photos. I should warn you to TURN OFF THE ELECTRICITY FIRST. Unless you’re absolutely sure that someone else won’t walk in and flip the light switch, don’t rely on just turning this off. Turn it all off at the main switch for the house.

Standard 2-pin BC Philips Genie and fittingStandard 2-pin BC Philips Genie and fitting

Here (above) is a Philips Genie 11W 2-pin bayonet CFL. It fits properly into a 2-pin bayonet fitting. When you try to fit it into the BC3 fitting (below), one of the pins will go into one of the J-slots OK, but due to the offset of the other slots, the other pin won’t go in. Ignore the third slot.

Standard 2-pin BC Philips Genie with BC3 fittingStandard 2-pin BC Philips Genie with BC3 fitting

But if you look carefully at how the non-fitting pin lines up with the slot (below), you can see that the bottom end of the slot, i.e. where the pin would sit if it could be got into the top of the J, is (just) to the left of the pin. (See the line I scratched on the fitting.) That is, if you could get it there, it would still sit in place without immediately falling out.

Standard 2-pin BC Philips Genie with BC3 fitting

So, with the pliers (making sure the electricity really is off), bend the edge of the non-fitting slot (the inside edge of the J) inwards and fold it back on itself, squeezing it as tight as you can (below two photos):

Bending BC3 fitting with pliers
Bending BC3 fitting with pliers

Now try the 2-pin bayonet bulb again (below) – it should fit OK, with a bit of wobbling perhaps. One pin should fit under the bit you just bent; the other should butt up against the inside corner of the J on the other side. It’s not perfect, but the friction there is enough to hold the bulb in place OK.

Fitting 2 pin BC bulb in BC3 fitting
Fitting 2 pin BC bulb in BC3 fitting

Switch on the electricity again, and there you have it: any standard 2-pin bayonet bulb, working, in a BC3 fitting (below). Given the amount of free CFLs handed out by various organisations, you could probably replace all the BC3 bulbs in your house for zero cost, once they come to the end of their lives.

Fitting 2 pin BC bulb in BC3 fitting
Fitting 2 pin BC bulb in BC3 fitting

Disclaimer: I can’t accept any responsibility for injuries, non-compliance with building regs, incidental damage, etc. The above is just a proof of concept, etc. Have fun.


  1. It seems to me this is a perfect opportunity for someone to sell 2-pin to 3-pin adapter sockets. The bulbs would sit up a little higher but you’d probably end up with a more secure mount.

  2. Dan

    It’s a good point. An adaptor’s available that’s effectively the base of a BC3 bulb with the starter/ballast included, so you attach the tubes themselves (which are cheap) to the base, but this isn’t the standard.

    Someone from an Australian company that makes T8-T5 fluorescent tube adapters left a message on a previous post suggesting that if someone could give them more details and send some fittings/bulbs over, they would look at producing a BC3-‘BC2’ (actually just ‘BC’ / ‘Ba22d’) adaptor. I should probably get on to that.

    P.S. I should also thank George Preston who alerted me to the existence of the BC3 system in the first place.

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  4. These are weird.

    I’ve gone my whole life without ever seeing any of these alternative “BC2” and “BC3” bulbs or sockets — only screw-base bulbs and the corresponding sockets. These posts almost seem to be coming from another planet or something.

    (Most fittings here now have CFLs. One or two that don’t are also rarely or never used. One of the main fittings is unfortunate, though — it has a dimmer, and the CFLs’ labeling warns against using them with a dimmer. Is this an issue if the dimmer is only ever left in either the completely-off or the completely-on position rather than actually used as a dimmer? I can’t replace the dimmer itself — lack of tools, parts, and expertise, plus the landlord might be annoyed.)

    • Mandie

      You are very lucky,I have 220 Social housing tenants, many of whom are on low incomes, who are sitting in the dark because they cannot afford the bulbs. I cannot recommend this DIY solution to them, but the problem definately exists in new builds.

      • florence

        mandie… if you have 220 social housing tenants sitting the dark because these bulbs are so expensive, then i suggest you do somthing constructive about it! i.e, get your contractors out there changing their light fittings over to somthing they can afford to replace! people like you are the ones to blame in the first place. you should be ashamed of yourselves! I am one of the people you mention, and to be honest the bulbs dont last very long, they are inferior quality, my landlords dont answer now when i ring and complain or to ask for suggestions as to what to do, so I am seriously considering the DIY approach! its either that, or change the fittings to 2 pin ones. or maybe the other option of supplying a standard 2 pin lamp in every room. We have a air source system too! so we are basicially running a total electric heating and water system too! we are not going forward in time, its medieval!

        • Anonymous

          I also have 3 pin lighting, my little boys room, my bedroom, landing light + front room lights have gone at the same time.I dont know where to get the bulbs from and if i did I cant afford to pay £10+ per bulb for 5 bulbs. I also have the air source system which plumbers don’t khow how to fix because they are fantastic new systems that brake down every few months through out winter. Happy 2011

        • annie

          dont want to move, just want to live in a housing association house that i can afford, lol .thought it was called social housing for a reason, but with my energy efficient eco friendly heating, costing me a fortune, my light bulbs, wheelie bins, street lighting , gardening,ect ect all being charged for seperatly to the rent, it would probably be cheaper getting a mortgage.when these 12 quid a time bulbs pop, im going back to candlelight, oh the good old days lol.

  5. Dan

    If you only use the dimmer in the ‘off’ position or the fully ‘on’, I don’t think it will damage the CFL, because it’s either receiving standard mains voltage AC, or none at all. But make sure that when it’s off it really is off (i.e. no hum at all coming from the unit). And to go from off to on – do it quickly. If you run a standard CFL from a standard triac chopper-type dimmer, it tends to flicker on and off at lower dimmer settings rather than change intensity like an incandescent filament bulb would. This is bound to shorten the life of the bulb.

    There are a lot of different bulb base standards around. One listed there which I hadn’t previously realised existed is the B22d-3 – 22mm Bayonet Cap 3 Pin (Railway) which I presume is an alternative to the BC3, perhaps used on railways so that it was not worth passengers’ while stealing the bulbs, since they couldn’t use them at home. Bit like the story of a shoe manufacturer which shipped containers full of right shoes separately from the left shoes, to reduce the likelihood of shoes ‘going missing’ en route.

  6. It’s odd for competing suppliers to take even THIS long to materialize, given that there’s no “secret formula” involved. Anyone with a bit of skill at mechanical engineering can probably devise a bulb base that will fit those BC3 sockets with no other product-specific knowledge beyond what can be obtained simply by examining one of the sockets.

    We’re not talking something difficult to reverse-engineer here!

  7. D3665

    that idea to bend back part of the light fitting is great, just done it and it worked perfectly. now i only have to spend £2 on a bulb and not £10 which has to be ordered. Thanks

  8. Andy

    Thanks for the advice. My Daughter has broken a bulb in her new flat and asked me to replace it. I have been to every local and High Street DIY place looking for a bulb to no availe. It’s crazy that this was ever allowed. I have bought a standard light fitting which I could easily swap out. I will try this fix first. I hope someone does bring out a retrofit solution and stop people being ripped off for these silly bulbs.

  9. CJ

    Thank you so much! I was not impressed when I broke my bedroom bulb in my new flat (little to ‘flipant’ with the duvet cover!) I bought a new bulb but it didn’t fit! My 1st thought was the house builders brother owns the 3 pin bulb company!!! Now I see its to do with conservation… not quite as irrate although … slightly daft as the courier has to deliver 1 bulb to me.. which no doubt causes 50 times the carbon footprint than my trip to Tesco which I was making anyway!!

    Anyway – thanks for the tip… I will get my pliers out tonight (and hopefully stop stubbing my toes on my chest of drawers!)

  10. Regarding the extent of low energy lighting needed in a new dwelling to meet the requirements of Building Control, Approved Document L1A, Para. 43 states:

    Reasonable provision would be to provide in the areas affected by the building work, fixed energy efficient light fittings that number not less than the greater of:

    One per 25m2 of dwelling floor area (excluding garages) or part thereof; or
    One per four fixed lighting fittings.

    A light fitting may contain more than one lamps.

    The Approved Documents are freely downloadable from the Goverment’s website, do a Google search for ‘Approved Documents’. Or go to:

  11. Bob

    It would not be so bad if the BC3 bulbs lasted for any length of time but they are not very good quality and do not last anything like their expected life.
    Also the cost saving of these type of bulb is completely negated by the additional expense the cheapest I have found is £9.50 plus delivery. So I have changed the fitting for the standard BC fitting. Nothing in the regulations prevent this it is only the newbuild people who have misunderstood the regulations and believe that they must make it so that the bulbs can not be changed for standard ones. Perhaps the answer is to make filament BC3 bulbs.

    Environmental impact once you have worked out the whole life costing in carbon footprint (I hate that term) you will find that the low energy bulbs unless left on for at least 6.75hrs each day actually use more energy.

    • Hugh

      Ah! in the sixties & removed mid seventies The incandecent (filament) bulbs in side road street lighting was also three pin, to stop people pinching them for their houses. (wish I’d kept some now).

  12. Stuart

    So is it possible to simply swap the fitting for standard ones?

    For about a fiver I could swap all of the stupid things in my new flat over, or I could spend 10 a bulb on these dim pieces of rubbish.

    If I can just swap the fittings I’m off to Wilko’s now, its a total no-brainer.

  13. Dan


    Just a word of warning re: the Lyvia lighting cheaper alternative. The pins are equally spaced unlike the BC3 in the diagrams (it’s actually the B22D) and won’t fit your new build light fittings – so there is no cheaper alternative!

    Best altering your fittings as above

  14. Over on an earlier post, ‘Al Capone’ has left a very useful comment with an alternative method of modifying the BC3 fitting:

    hi all as to the BC-3 light fixture’s they nothing but a complete rip off.. moved into brand new house only 3months ago 2 of these £12+ long lasting bull sh*t bulbs have blown in less than a month..
    so here’s how daddy cool who aint no fool.. done a 5min modification on the BC-3 light fixture’s to take the normal 2 pin light bulb as well as the 3 pin rip off bulbs

    first off if ya completely clueless about wireing then its best you dont have ago yaself.. either buy a book on home electric’s and have quick read on the subject you’ll soon pick it up just as easy as putting a plug on ya toaster .. but if ya a politition or something its best you pay the £12 as you prob still dont know how to tie ya own shoe laces yet and have to pay someone to do them for you..

    make the 12 o’clock slot in the BC-3 fixture about 2mm wider i used a dremmel but a pair of cutters will do the job just as well then on the 6 o’clock slot where the blub pin holds in place cut the slot so the blub pin can twist about 2mm further round.. and bobs ya uncle ya just saved ya self from being forced into buying a poor quality light bulb that costs £12+ in which you’ve prob spent £20 in petrol driving round tryin to find a store that sells the useless things.. save the planet ??? i ask you!! as for having to be qualified to connect 2 wires in a light fixture.. maybe those who make these rules & regs still need mummy to wipe their back sides every day in life.. or will we all have to be qualifed to use the toilet sometime in the near future..

    Thanks Al.


    its a complete joke having to mail order to buy a light bulb how many old people will have to fall down their stairs in the dark before those who think up these stupid change’s & regulations have some common sense in their lives.. the 80yr old lady who lives across the road from me came back in tears after spending 5hrs walking round town trying to find a shop what sells these stupid light bulbs in which she had no luck. obviously i gave up an hour of my time and done the right thing & tweaked all her light fixtures to take the 5 normal energy saving bulbs she’d already bought by mistake on her old age pension. its about time these retards who run the country take a very long test in common sense before they even are allowed to have a job whats being paid by the tax payers money..

  16. Andrew

    Just bought a new Bovis house and found that it had 5 BC3 fittings – the lights in the hall and landings. I replaced all the BC3 lampholders and lamps with standard ones at minimal cost. Incidentally the replacement bulbs were 8W compared with the 15W bulbs provided with the house so around half the energy consumption.

    I was fascinated by the fact that the show house on the estate had none of the BC3 fittings in place. All were tungsten halogen spotlights which seems a pretty good indication of the house builders real commitment to energy efficiency!

  17. wickedstef

    Thank you!

    Just moved into a new build appartment and with your no cost workaround I can use my typical CFLs which are as energy efficient and apparently much more reliable. Indeed 3 of the prefitted BC3 were already, hmmm, removed from their lampholders…

  18. John

    Brilliant suggestion. I kind of followed your advice, but managed to cut through the thin fitting using a pair of nail scissors – for anybody who doesn’t have a pair of pliers…

  19. Good article and I agree the above is a joke, with normal bulbs about to be banned we have reached a point where good quality Philips and Osram bulbs are available for less than 10p each, the cheapest MEM I can find is over £8!!

    Although the above looks fine (and safe) I would prefer to change the actual fittings, all of my MEM fittings are of the Pendant style and MK do a replacement lampholder (the bit you screw the bulb into) for less than a pound from B&Q and probably even cheaper from electrical wholesalers / Screwfix etc. It takes 5 mins to swap or for those wanting to change the whole fitting they are only about £3 including the ceiling rose.

  20. Wellmift

    I have a 500 year old Grade 2 listed house. I have recently has it rewired as part of an extensive restoration. To confirm with building regs, my sparky has installed 6 0r 7 of these pesky BC3 fittings.

    Do you think he has misinterpreted the building regulation guidelines? I mean, I can almost see the logic for new build places, but it seems a bit OTT for a listed building renovation.

  21. awomen

    I bought my Twigden house(new built) in Dec 2008 and it has two BC3 fittings in the hallway area. One of the lightbulb broke after just after 6 months and the other has just gone (these lights were not often switched on)!! Whilst the outdoor energy saving lightbulb from Ikea is still in perfect working condition even it is switched on regularly from evening till morning. I am now very glad to have found this site as I really want to fit the 2-pin Ikea energy saving lightbulbs into these annoying BC3 pendants. I don’t have any knowledge of electrical fittings but the explanations and illustrations are clear so I hope I can do it properly without injuring myself. Thank you for posting this Dan.

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  23. Claire

    I moved into my new build house on 2nd June 2009. within 48 hours one of the bc3 lamps fitted as standard had died, I have been trying to find a replacement ever since. Thanks for the tip Dan, this is one of the worst thought out pieces of eco design I have ever encountered.

  24. Chrissy

    I moved into an Orchard new build house in October 2008. The whole house has these stupid fittings and I was lucky if the bulbs lasted 6 months, some of the replacements lasted even less!

    I gave up in the end and started using uplighter standard lamps instead!

    Thanks so much for this tip.

  25. Sparrow

    Just a word from the industry. Most sparkies I know are as annoyed about this as their customers. Some are even going back after the final inspection and replacing the BC3s with standard fittings. With the phase-out of tungsten lamps the whole silly business is completely redundant anyway

  26. M Kilby

    I’ve found these BC3 bulbs unreliable, certainly not much more reliable than regular tungsten ones.

    When the bulbs fail I’ve had glass and foul smelling fumes pumped into our rooms. I heard they contain mercury (amongst other things I imagine).

    I have no desire to use tungsten bulbs, just wish to use the latest and greatest energy saving models but cannot as the fittings are incompatible.

    I’m going to replace all the adapters with regular ones as they fail.

    This is absolutely the wrong way to go about changing attitudes / behaviours.

  27. Neenabecks

    Glad I’m not having to resort to robbing bulbs from show homes as someone suggested today!! We have been walking round in pitch dark for some time now in our rental as not able to buy these ridiculous bulbs, but am swapping all the hall fittings for other rooms where we don’t use the ceiling lights.

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  30. diane

    im in a new build with these light fittings in so thanks for the advice. i’ve 2 of these fittings in the corridor and, to be fair, after over 2 yrs, one of the bulbs as gone. the other is still goign strong, so maybe the bc3s aren’t that bad after all…?

  31. Alyson

    I tried this as I have a new build and Im tired of these bulbs failing. I bent round the edge of the J shape as directed above and managed to get the normal bulb to fit. When I turned it upside down the weight of the bulb pulled it down and it wont stay fixed in position no matter how much fiddling about I do with the bit I have bent inwards to try and get it to grip. I am buying new lamp holders and replacing them, I have wired in light fittings before. Its easy enough, just a matter of putting the new wires where the old ones came from.

  32. I to have lived in the UK for 48 years and have never seen this problem before, but I do live in a older house and so do most of the people I know, I would bet more than a penny that I start to see or notice this problem all over the place now that I am aware of it

  33. M.L.

    Very annoying, but a very good workaround. Thanks to you, my light is working again since the bulb went in 2009. I’m in a new build also with 3 BC3 fittings and a couple of normal ones. I was told “Yes you can buy an adapter in Morrisons” but that was a load of bull, I haven’t been able to find any adapters let alone any 3 pin bulbs for sale. So bending metal bits it is, thanks again!

  34. Bill

    Why don’t you just buy replacement lamp holders, you can get them for less than 50pence and it will only take a few mins to change it it’s only 2 wires and it doesn’t make a difference which way around they go. personally I haven’t seen one of these BC3 fittings and my bungalow was rewired by the housing trust 12 months ago.

  35. annie

    i moved into new build, housing association just over a year ago, and unfortunatly these 3 pin bulbs are in every room.So far in this short space of time , ive got through 5 bulbs. The housing association say they had to put them in, something to do with building regulations,but i can purchase them from the association, at a very reasonable price of 8 quid each.i wrote to the manafactures to tell them what a heap of cow dung they are, and asking how i am saving money over the course of a year, if they keep blowing every 5 minutes, and apparently its unusual for them to have such a short life span, they usually last 8;000 hours and are the best thing since sliced bread, yeah right, bit of propaganda there i think.but looking on the bright side,(excuse the pun) they did send me 6 free bulbs , without predudice, so that should keep me going for a few more months.

  36. Pete Osborn

    Interesting workaround. I’m no H&S freak and have done my share of “creative solutions” but I’m more than a little frightened at the thought of someone attacking the fitting with a pair of pliers. It is possible that the bulb could make poor contact leading to arcing, excessive heat and possibly cause a fire. If you think you’re competent enough to do this, just replace the whole thing with a standard fitting. Switch off the mains first. There are two wires – it doesn’t matter which goes where. Permanent, safe solution.

    • Andy T

      Yes I would agree. If you feel competent enough to bend the fitting then I would only do so for a “stop gap” fix until you buy some replacement 2pin fittings. I also hear the government at long last realised their stupidity and in Oct 2010 the regs were revised – the original ones only required provision that you COULD use energy efficient lights not MUST anyway.

  37. S Ford

    This article inspired me to give it a shot and fix this problem. I had noticed that the difference in alignment between bc and bc3 was minimal, but wasn’t confident doing electrical stuff myself.

    However I did it a slightyl different way which could easily be reverted without anyone knowing. I just gently bent it outwards. Should I need to revert I can just push it back.

    Fortunately the bc3 fitting was made of very poor quality metal and very thin, meaning bending was really easy.

  38. souvenir

    Easiest and safest way to do it…
    Break one pin off a normal light bulb and put it in. Make sure which one needs to be off before you ruin the bulb…

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  40. I posted similar to this 2 yrs ago but got no response.

    If anyone would like to send me the base only ( no glass) of 2 dead 3pin globes
    and preferably 2 pcs x 3pin sockets.

    I will contract manufacture of an adapter which will fit into the existing 3pin socket and allow any
    globe with the following bases to be used.

    1. 2 pin bayonet globe (B22)
    2. Screw base globe (E27)
    3. GU – 10 base globe etc.

    At the same time I will offer
    the latest SMD/LED to fit any of
    the adapters.

    This will allow you to use SMD/LEDs
    in place of whatever lamp you are currently forced to use.

    A 3.5 watt SMD/LED may be on par with an old 60watt incandescent.
    Or probably on par with a 15w-20w

    Which means you may save from
    80% – 94% on electricity consumption with use of SMD/LEDs

    If you want brighter then
    5watt 7watt 10watt etc, etc, is available.
    Conditional Warranty: 3yrs.

    In the recent past LEDs for domestic use were not bright and also unreliable.

    Today they are very bright and very reliable and very low wattage.

    These globes have a 30,000 – 50,000hr life.
    Which means
    10 – 18 yrs when used ( 8hrs day)3000hrs pa.

    If 15p kwh is average cost of UK electricity then
    replacing a 20w CFL with a 3.5w SMD
    may save around GBP 7.50 pa.

    Given the cost of electricity is forecast to rise yr on yr by a minimum of 10%, The GBP 7,50 saving 2011, will become a saving of GBP 20.oopa 10 yrs later.

    Using LEDs and and adapter to by pass the the cost of 3pin globes
    is a sure way to save money.

    So if anyone wants to assist bring
    this project to fruition I will happily pay the postage and cost of the 3 pin globe bases and sockets.

    Anyone wishing to try their hand at selling these once available is welcome to contact me

    61 7 3716 0899 ~ 61 0432 202 838
    email is best

  41. Barmonkey

    like souvenir said just cut 1 pin from a 2 pin bulb, it only needs 1 pin to hold it in place, my flat had the 3 pin sockets in every room so i went to tesco and bought 10 for £2 and cut the pin off,

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  43. Ali

    Well I read the details and thought “what have I got to lose?”. Being a single woman, living alone, DIY is not something I relish. However, it took me about 2 minutes to sort and I now have light in my hallway. Hurray, Dan you’re a genius!

  44. dan all i can say is that is it so heartening that someone from the ‘green’ establishment as such, has common sense, and not be taken in when things a purely a money making government endorsed fiddling with a problem that did not exist £10 a bulb!! and thats on e bay !

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