1 Way 2 Gang Switch Issue

[swfc247]

Hi Folks
After a bit of help, i'm trying to solve an issue with a light switch and determine if it's the cause of a lighting problem.

As a bit of info, I have 2 sets of low voltage downlights in the kitchen ( 2 packs of 3 = 6 in total) both connected to a single light switch.

For the 3rd time in three years 1 set has packed in. Always the same set in the same position. In order to eliminate a possible cause I was going to replace the light switch (ever the optimist) On opening the switch ( 2 gang - the other light is over the cooker and has never failed) I was met with only 3 wires 2 x Red and 1 Black. The other Black wire had been snipped. There is then a small piece of wire connecting Com A to Com B.
Wiring is a follows

http://media.diynot.com/212000_211970_90072_49104652_thumb.jpg

1st cable
Red to Com A Black to A1
2nd Cable
Red to B1 Black cut

Wire from Com A to Com B

Can anyone (in simple terms) explain what is going on and if that in any way would contribute to my lights failing ?
cheers[/img]

 

[EFLImpudence]

Can anyone (in simple terms) explain what is going on

You have one supply wire which needs to go to two switches.
Then one wire to each light.

and if that in any way would contribute to my lights failing ?
cheers

Nope.

 

[delmel]

Inclined to think it's more likely cheap and nasty transformer and or fittings. The transformers are generally so crap, especially if you got from a day store. If you can pull out the old one and exchange for a decent one. I would recommend Ibl.

The other main cause is many of these allow for 20 or 35watt lamps only, people then like the brighter option of 50watt Which will physically fit, and the transformer / fitting will either not work or burn out very soon.

 

[Taylortwocities]

You COULD swop over the switched lives in the switch to prove that it is not the switch, but it probably wont be.

To clarify a couple of points:

You say that these are low voltage lights. That means over 50volts. Did you really mean extra low voltage (12v for example)??

When the lights "failed" in the past, how did you get them working again?

 

[swfc247]

Hi Thanks for the prompt replies

The lights are the 50w versions, previous version was from Ikea, prior to that Screwfix. Last time I got them to work I replaced the dud set completely. I have 2 new sets of 6w LED downlights to replace these, but didn't want to just replace them immediately just for them to go, hence the questions. I'll replace, just seemed strange that the same set out of the two fail repeatedly.
Cheers

 

[swfc247]

Hi

I've ordered an IBL transformer, worth a go for £15. I'll let you know how I get on.
Cheers

 

[Taylortwocities]

You can get 50watt lamps that are 12v and some are 230v.

Which sort are yours??
\

 

[delmel]

Please note if I am understanding you, you have replaced the 12v 50w lamps with led 12v ?.

If so there lies your problem, the led although may work with an existing transformer, they are not made to, if they work they will do so but will shorten the life of both lamp and transformer. They are also likely to flicker or buzz.

Led need to have led drivers. Ibl also do those although I do not know the quality of them. There transformers are certainly one of the best, probable mode are the only better ones.

 

[ericmark]

previous version was from Ikea

That explains things it does seem Ikea have some very poor electrical goods. The picture

Light Switch

• swfc247
• 15 Feb 2015
• 1

I can't make my mind up is the black wire damaged?

As said 50 - 1000 AC is low voltage so in the main low voltage is 230 volt with no transformers or other voltage droppers involved.

Extra low voltage could be anywhere 0 - 50 volt but often is 12 volt. This does need some method to reduce the voltage. There are two common methods one is a simple transformer the other is an electronic device which contains a transformer which turns AC to DC then back to high frequency AC then transforms to voltage required. The electronics also monitor the voltage output and change the parameters to ensure spot on 12 volt.

The simple transformer has a maximum wattage or amps. The more complex also has a minimum as well. Often there is an auto shut down when the wattage is not within parameters which can be misleading when all lights fail when one bulb blows simply as not enough load.

There are problems with extra low voltage when using low energy bulbs and now many systems are being converted to low voltage as the regulation contained in the voltage dropper (often labelled electronic transformer) is now built into the LED bulb.

Once converted to low voltage then easy to separate onto an array of switches but not so easy with extra low voltage so step one is to find out what you have.

 

[delmel]

Transformer for £15

Where from ?

 

[swfc247]

It says 12v on the last replaced set, no idea about the original without going back up !

 

[swfc247]

Hi

Sounds like I've caused some confusion. try again

I haven't changed anything as yet. Prior to changing anything I wanted to know of I had any kind of fundamental problem, especially with the same set (out of the 2) going each time. All I've done is unscrew the switch. I have 2 new sets of lights to replace the whole lot which are LED 6 w. The current sets are attached to a transformer in sets of 3, therefore 2 transformers daisy chained together and it is the second set that keeps failing.

 

[delmel]

Ok as before probably a rubbish brand of transformer is the reason for failure.

If you are replacing the whole lot, don't bother ordering another transformer as you will no longer be using it.

The led will have to have drivers, look the same as a transformer but run differently and with a stable voltage output.

Both led and transformers will be made both quality and poor, so again beware, although cheaper drivers are seemingly performing better than cheap transformers.

Likewise the led lamps if poor will give a poor performance. There are so many of them on the market. The cool white in my opinion are nicer for kitchens and bathrooms.

 

[ericmark]

Led need to have led drivers. Ibl also do those

Some LED's do indeed need drivers however most LED bought over the counter have the drivers built in and so only require a stable consent voltage.

With a transformer the output is rated as 12 volt RMS so although it peaks to 17 volt a filament lamp has not problem. However an LED may have a problem as the package needs to convert the AC to DC and smooth the DC which can mean well over voltage. With a switch mode power supply this can be a low worse although 12 volt RMS the peak could be 24 volt.

The way around the problem is to use a DC supply voltage controlled this is NOT a driver. A driver is current controlled it is a simple power supply.

Some strip LED packages do required drivers and these are rated as max and min voltage but a set current output not a max and min current with a voltage output.

There are some power supplies incorrectly labelled driver rather than power supply there are also switch mode power supplies labelled as electronic transformers. It would seem the lighting industry has tried to use the old name when a new product is released so a switched mode fluorescent tube controller is still called a ballast after the choke which originally did that job. So be it a HF ballast, Electronic transformer or a 12 volt DC driver the names are taken from the old device they replaced. However the driver is also the correct name for a current controlling device so you need to read the spec rather than name.

Some 12 volt LED packages will work AC or DC under a wide range of voltages. Others will not. As as much as I have looked for the spec on a GU5.3 bulb I have failed to find it so don't know if it would be OK at 14.8 volt in a caravan or not or if DC only or AC/DC. Oddly since no polarity they have to include a rectifier so can be plugged in either way around so will work AC or DC but question is with AC how long for?

Again oddly with 230 vac GU10 lamps the spec is often published and in some cases 150 - 250 volt range of input voltages.

With the utter confusion created by the lighting industry the easy way out is to move to low voltage (230ac).

 

[delmel]

If it's the 12v led you will need some type of driver, there are the standard mains 220-240volt which will run and do not require a separate one.

I am unsure of the type he has now purchased