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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

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    • CommentAuthorRex
    • CommentTimeDec 8th 2023
    What ho one and all,

    Have a 12v 5W halogen in the garage door opening motor that has given up the ghost. Would like to replace with a wider beam angle bulb and LED seems to be the way to go.

    But seems that it is not so easy to just plug one in (balanced transformer / flickering) or am I missing something?

    Will any of China's finest 12V 5W LED bulbs be plug and go or do I need to fiddle with things?

    • CommentAuthorowlman
    • CommentTimeDec 8th 2023
    If all fails with sourcing MR 16, would it be possible to disconnect the transformer and re-wire in 230V and replace the bulb holder with GU10?
    You may find a wider choice of beam widths and outputs etc in LED GU10.
    • CommentTimeDec 8th 2023
    Given that a 5 W LED is usually stated to be roughly equivalent to a 35-50 W halogen, are we sure the stated numbers are correct?
    • CommentAuthorRex
    • CommentTimeDec 9th 2023
    Thanks for the thoughts.. I do kinda like the rewire for a 240v GU10 idea. Presumably, that would be as simple as taking the +/ - 240 directly to the GU10 holder?

    As for the bulb holder itself, there is only the ceramic base with the two wires, not actually fixed to anything, just floating. The bulb is kept in place by a C shaped spring around the edge circumference.

    A for the number on the bulb, only listing what is printed. The brightness is not so important as the light only runs for three mins as a default when the door is opened or closed. It is not a garage illuminating light.
    • CommentAuthorowlman
    • CommentTimeDec 9th 2023
    Yes, easy enough to swap lamp holders:-

    • CommentAuthorRex
    • CommentTimeDec 16th 2023
    May be a silly ask but.....

    I have inadvertently ordered and had delivered a 240v LED MR16 rather than what I though I was ordering, a 12v.

    Given Owlman's suggestion above, is there any reason that I should not by-pass the transformer and just attach the 240v wires directly to the existing MR16 bulb holder? Would both wires and holder be designed to handle 240v?
    • CommentAuthorowlman
    • CommentTimeDec 16th 2023
    AFAIK 230V MR16 ( i.e. an MR16 with an internal LED driver ) are used in some countries, I'm unsure if the UK allows them. The GU10 is the usual mains voltage alternative reflector type lamp.
    • CommentTimeDec 16th 2023
    240 V is a lot more dangerous than 12 V and you will need to check that where it is mounted complies with the relevant safety laws.
    • CommentAuthorRex
    • CommentTimeDec 17th 2023
    No idea about the relevant safety laws!!! The current (non-working) bulb is plugged into the holder and just sits in the motor plastic housing by a circlip around the reflector circumference. Given how hot a halogen bulb becomes, imagine that a cooler running LED would be OK.

    Would be happy with a 12v LED MR16 but seems that a single bulb will not run from the existing transformer. Is that right? I just want to plug in a replacement LED wider beam bulb but everything I am reading mentions the need for an LED transformer or a number of LED bulbs to equate to the wattage output of the existing transformer.
    • CommentAuthorowlman
    • CommentTimeDec 17th 2023
    As the existing is halogen then the chances are you'll need a new LED driver. if you want to stick with 12V.
    If you want to ditch 12V in favour of mains then best to go GU10.
    I can't remember where I once read about mains MR16 not being compliant. It may well be OK; I'm guessing here but it may also be something to do with the flimsy pin connectors, the twist and lock GU10 being more secure for mains usage .
    If 230v MR16 bulbs are sold then they must be compliant - otherwise they couldn't be sold.


    Whilst these are over here they must be EU compliant so should be OK for UK despite Brexit.
    • CommentAuthorowlman
    • CommentTimeDec 17th 2023
    @ Peter;
    OK, compliant was maybe the wrong word. Rex inadvertently bought an MR16 reflector with a GU5.3 base instead of a GU10 base.
    I was attempting to answer whether a GU5.3 base is permissible for mains voltage in general household use, as opposed to factory fitted specific equipment, which can be the case.
    Possibly this may lead to confusion and people replacing 12V GU5.3s reflectors with mains voltage ones and vice versa. Hence the GU10 base being the more usual mains voltage option.
    I don't know if this is the case just surmising.
    • CommentAuthorRex
    • CommentTimeDec 17th 2023

    Thanks for the thoughts. I did not actually buy a MR16 reflector with a GU5.3 base, the garage door operator came with it fitted.

    Seems the best option is to buy a GU10 base and wire it directly to the incoming mains. My guess is that the motor itself operates from a transformer.

    Will give some thought to opening the unit and have a browse.
    • CommentTimeDec 17th 2023
    Posted By: RexSeems the best option is to buy a GU10 base and wire it directly to the incoming mains. My guess is that the motor itself operates from a transformer.
    Depends whether mains is fed to the unit and the voltage reduced by a transformer inside it, or whether the voltage is reduced by a wall wart and only 12 V is supplied to the opener.
    • CommentAuthorRex
    • CommentTimeDec 18th 2023
    240v supplied to the motor. 12A plug/socket on the ceiling.
    • CommentAuthorRex
    • CommentTimeDec 18th 2023
    Whilst in a meditative moment, I realise that it is not possible to go with a 240v GU10 bulb. When I open the garage door, the light activates for around 3 minutes and automatically switches off. Any bulb that by-passes the electronics will not do that and most likely will turn on but not off.

    But I have found this which does tick one box, that of a wider beam angle.


    Given what I have read that I need an LED that says 'the equivalent of' and this exceed the halogen of 35W, is this likely to work flicker free? Although it does say it needs a LED transformer and I don't imagine it is possible to wire one into the motor housing so that it does give the 3 minutes.
    I assume the door motor is 230 v
    You can get adjustible timers for bathroom fans that come on with the bathroom light - in your case the start of the door motor - and will stay on until the light (door motor) stops and then over runs by the set time then turns off.
    The wiring is permanent neutral, permanent live and a live feed from the switched power to the motor.
    • CommentAuthorRex
    • CommentTimeDec 19th 2023 edited
    Took the advice of a neighbour and bought a somewhat expensive (£6.87) 12v, 5w LED from Screwfix, 60 degree beam angle.

    Plugged it in and it works, so will stay with that.

    As an aside, the box energy graph says it has an energy rating of G. As a low wattage LED, how is that possible? Though all LED lights got up near the A or B mark.

    The box also says, 360 Useful Lumens and 500 Total Lumens. What does this mean?

    Thanks for all the advice; have a Cool Yule!
    • CommentAuthorMike1
    • CommentTimeDec 20th 2023 edited
    Posted By: Rexthe box energy graph says it has an energy rating of G. As a low wattage LED, how is that possible?
    New ratings came in a couple of years ago, with new assessment methods and a major downgrade to avoid nearly all LED bulbs being rated A / A+ / A++ / A+++.

    Posted By: RexThe box also says, 360 Useful Lumens and 500 Total Lumens. What does this mean?
    For a directional lamp (yours is supposedly 60°) rather than a non-directional one (intended to light a room in all directions), the 'useful lumens' is the amount of light that falls roughly in the direction that it is supposed to. In your case 140 lumens falls well outside this direction and therefore doesn't get taken into account in the efficiency calculation, Which will be a significant reason behind the G rating.
    • CommentAuthorRex
    • CommentTimeDec 20th 2023
    Thanks for the explanation.

    Regulations changing. What a racket! Does that mean the only way to get a bulb with an A or B rating is to use no electricity whatsoever?

    Recently had an EPC check done on a 1960's maisonette that I rent out. Ten years ago, it got a D rating; this time, it got a D again but the score was much closer to C. However, I was told that next year, the rating parameters change and it would be rated at least E, if not lower.
    • CommentAuthorwookey
    • CommentTimeDec 21st 2023
    Posted By: Rex
    The box also says, 360 Useful Lumens and 500 Total Lumens. What does this mean?

    360 is the amount of light that falls in the 'useful' area (however that is defined). The other 140 goes elsewhere.

    The original design of the MR16 was for halogen bulbs, and it is normally a dichroic lamp - i.e. the visible and UV/IR light are separated with the visible light going forward and the UV/IR light back ( so as not to damage/overheat whatever was being illuminated). That splitting may account for 1/3rd of the output going elsewhere, or it may simply be to do with how much is actually collimated by the lamp body. I'm not sure if LED versions of these lamps still have the dichroic coating or not. (in an LED about 50% of the energy ends up as heat - in the Halogen version 90% was heat, 10% light so it's less necessary, but still useful).
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