I have a new dimmer for Led lights. I need to dim 4 leds of 5-watt each one. The dimmer is for 220 V AC.

The problem is that I see 4 connectors in the back. But I have only 2 wires in my wall. If am I understand things correctly I need to wire 2 new cables from the bulbs to the socket in the wall. There is any alternative? Am I missing something?

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  • 2
    You've bought a low-voltage dimmer. Input 240v, output 10v. You can't dim mains-voltage lights with that. What lights did you get? …and stop playing at guesswork, you'll blow up the dimmer or yourself if you're not careful.
    – Tetsujin
    Jan 2, 2022 at 16:24
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    Is this the next chapter of diy.stackexchange.com/questions/241600/… ? Did you finally blow that one up? Get a professional, before you kill yourself. The guesswork in comments under that was sufficient to know you have not the faintest idea what you're doing. You need to stop now before you do some proper damage.
    – Tetsujin
    Jan 2, 2022 at 16:25
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    Dimmers wire up exactly the same way as the light switch you just removed. They even have exactly the same labelling - so long as you bought the right one. You photograph the old switch inc labels & existing wiring, take the photo to the DIY store & say "I need a dimmer to replace this". Then you move the wires from the old switch to the new, one terminal at a time so you don't mix anything up. Done. No-one dies. Anything more complicated & you hire an electrician.
    – Tetsujin
    Jan 2, 2022 at 18:50
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    Changing a dimmer is perfectly reasonable... if it goes smoothly. The problem is, when it doesn't, you start "trying random stuff and hope to get lucky", when you should really stop and research. And as we say, some connection combinations which "seem lucky" (e.g. involving earths) can set a deadly trap. But talking to us is definitely the right thing to do at that point, even if we can be salty at times :) Jan 3, 2022 at 0:44
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    The simplest dimmer has 2 connectors and 20 pages of instructions. If you buy one with 4 connectors, all labeled in unfamiliar ways and no instructions, it's just wrong to assume that you are going down the right path, and all you need is a bit of coaching from the internet and trial and error. If you haven't developed the intuition to know when to stop and step back, I say this in a kind and constructive way, you should not be doing DIY at least not with electricity.
    – jay613
    Jan 3, 2022 at 10:36

1 Answer 1


You bought the wrong dimmer. This dimmer is meant for commercial lighting that uses separate dimming wires. It will not work with your regular bulbs that use only two wires.

  • I thought commercial stuff more commonly used 1-10v than 0-10v, but you're right it won't work either way...
    – dandavis
    Jan 2, 2022 at 22:07
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    @dandavis There are two standards, but both are called "0-10v" in marketing materials. Commercial stuff uses IEC 60929 Annex E, which says that 1 volt is the "minimum", but different manufacturers implement that in different ways in practice: some say that means 1 volt or less is off, and some say 0.3v-1v is the minimum available brightness while 0v-0.3v is off. The actual difference between the two standards is that commercial lighting uses "current sink control" and theater lighting uses "current source control."
    – Moshe Katz
    Jan 2, 2022 at 23:54

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