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Any Electricians Around - LED Bulb Problems!

Suave

Distinguished Member
Hi All,

I have a 4 Lamp Track Light (in my bedroom & directly over my head) which has had 4 x 50watt Halogen GU10 bulbs - this connected to the 240v mains & is controlled by a single GET Ultimate Electronic Dimmer.

Today, I bought some 5watt LED bulbs from Screwfix to replace the Halogen ones but upon fitting them, strangely, two annoying things are happening - one, is that even when one switches off the Dimmer, the LED bulbs still stay on & although it is at a reduced output, it is still enough to distract one when trying to sleep. The second issue is that there is a very noticeable humming/buzzing that is coming from the lamps themselves & it is really annoying. My clock radio in standby even started making the same sort of sound strangely & I had to switch it off at the mains.

The reviews for the these LED bulbs were very high indeed & I do not recall any of them mentioning either of these two issues occurring so am wondering if anyone knows why & how to rectify things?

Would changing the Dimmer Switch do the trick & if so, which out of the many out there will likely solve things? Mine is either a 300VA or 350Va as the GET Brand got taken over by a company called Schneider & they may have changed some specs as I bought mine quite a few years ago. I have found a pic on the net that might hopefully be the exact same or very similar to mine that shows the module at the rear.

If it is not the Dimmer that is causing these issues, then what else could it be? I have attached pics to better portray what I have in case it might help.

On another note, does anyone know where I can get Square MR16 LED Bulbs - ideally with a wide/extra wide beam? My Googling efforts proved fruitless!

Many Thanks,
Suave!


Screen Shot 2015-12-14 at 23.02.19.png Screen Shot 2015-12-14 at 22.06.59.png GET Dimmer Rear.jpg Screen Shot 2015-12-14 at 23.27.30.png
 

John7

Prominent Member
I suspect it's your dimmer switch....you're only pulling 4 x 5W (20W) through it and it's minimum rating is 60W, so not enough load on it

You need to change it for one that's compatible with LED lamps
 

outoftheknow

Moderator
Although stating the obvious - the lamps are dimmable as well? Then the dimmer as above. Good luck :)

Edit - the described staying on of the lamps with the switch 'off' - not at minimum dimming - may indicate something else. A switch that is off will result in zero switched (and dimmed) supply I reckon and I can't think immediately why that would result in any type of lamp remaining lit. The dimmer does include a switch I presume......
 
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sep8001

Prominent Member
When we had led's put in the kitchen we were told we would need a special led dimmer switch, the one we use with the halogen bulbs is no good. However as above also ensure you have dimmable led bulbs.

We went with the non dimmable switch with a view of changing in the future.
 

russ123

Established Member
I had the same issue with the bulbs staying on slightly with some LED GU10s I picked up on Amazon 3rd party a few years back. I didn't have them on a dimmer though so it might not be that.

Never did get to the bottom of it. It was in a study so didn't disturb me but I was a bit worried about them, especially when I read about dodgy ones overheating. One failed so I binned them all.
 

Stuart Wright

AVForums Founder
Staff member
I've replaced most of the 81 light bulbs in our house with LEDs. As the other folks have said, you have to specifically get dimmable LEDs if you want them to dim, and they usually cost a bit more than the regular ones. You also need dimmer switches rated for LEDs.
The LEDs I put in the master bedroom are dimmable but the switch is not rated for LEDs and on anything but full-on, they flicker horribly. I just haven't got round to replacing the switch, yet.
Even when you put an LED dimmer in, it can be a bit hit and miss. The dimming characteristics are not always linear in the way you want them to be.

Maybe an electrician can answer this question. Is it preferable to have a dimmer switch with a variable minimum and maximum load or one which specifies, say, 10w to 100w ?
 

John7

Prominent Member
Easy way to prove the dimmer.......replace one of the LED's with a 50 W Halogen (thus increasing the load on the dimmer above it's minimum) and see if the problem is cured!
 

delanoster

Established Member
I have this exact problem with my dimmer switch and lights; I have 6 light fittings and if I use LED bulbs in all of them then they don't turn completely off. As a work around until I buy a new dimmer I've got a single 50W bulb in one of the fittings so the rest of the bulbs turn off.
 

Suave

Distinguished Member
Hi All,

I should have stated this in my opening post so apologies but the GU10 LED's I bought are the dimmable type - if you look at the pic of the LAP LED Bulbs, it says dimmable in the description - these are the exact ones I have but I hadd no idea that LED's needed special dimmers.

I am happy to replace the Dimmer as a starting point to see if it resolves the two issues but must admit that I have no idea what to get or what might work - they all look pretty much the same to me!

What in the specs should I look for just to be sure so I do not have to keep trying multiple switches in the hope that one might be suitable? If anyone can be kind enough to provide some links of some reasonable priced ones designed for LED's or will work with my set-up, it would be greatly appreciated!

Anyone know where I can get Square MR16 LED Bulbs at about 5watts each - my searches have come up with zilch!

Many Thanks,
Suave!
 

John7

Prominent Member
Have you tried what I suggested to prove it is the dimmer at fault? Pointless changing it if it's not the problem!
 

Suave

Distinguished Member
Have you tried what I suggested to prove it is the dimmer at fault? Pointless changing it if it's not the problem!

Hi,

Yes - the standard Halogen bulb switches off completely & the 3 remaining LED ones now dim down to a much lower level than before but are still illuminated ever so slightly.

It also does seem less noisier but will only be able to properly tell when it is very quiet in the house - there is still some buzzing though.

Strangely, since last night, the 4 LED bulbs switched themselves on even though the Dimmer Switch was off - this happened a few times so I will leave the one Halogen bulb in there for now & see it the same still occurs.

Does the above indicate Dimmer Switch problem to you?

Many Thanks,
Suave!
 

porscheman

Established Member
I had the exact same problem, and I can tell you that the problem is caused by induced current. Because LED bulbs only need a tiny amount of power to light, they can easily be affected by stray current in other twin and earth cables etc in your ceiling void etc. It is highly likely that there is no fault at all with your light switch.

To fix the problem you should (or contact an electrician if you are in any doubt about your competency) fit a capacitor to the ceiling light fitting. It is difficult to know exactly what microfarad capacitor you will need, so it might be best to buy a 4uf, 6uf, 8uf etc and try each one in turn until the strobing/always on problem is fixed. Of course if you are doing the work yourself, make sure you isolate the complete double pole main/RCD circuit breaker to the house at the consumer unit, rather than just the lighting cct breaker, to be on the safe side.

Here is an example of what the lighting capacitor looks like (the electrical wiring just snaps in to the connectors, no tools needed). Be aware you will need suitable space either in the ceiling light fitting itself, or in your ceiling void to fit the capacitor. They are roughly the size of a 'C' or 'D' type battery depending on the uF rating
- UNIVERSAL 6uF CAPACITOR 6 uF MOTOR RUN LIGHTING ELECTRICAL MACHINE 250V FASTPOST

Please let us know how you get on.

James
 
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IronGiant

Moderator
If his dimmer is not rated for LED use, which a lot of GET ones aren't then the dimmer is quite likely at "fault".
 

porscheman

Established Member
^^ Apologies I thought he was using just a simple 1 gang 2 way on/off switch. I'm too tired !! :D
 

IronGiant

Moderator
No problem, it's useful information for anyone with a similar problem using a standard switch :thumbsup:
 

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