Installing a dimmer switch

[Anticmosquito]

I took off the switch in a bedroom to replace it with a dimmer switch. When I removed the switch (after turning off the supply) I noticed that there were 3 lives wires.
The earth was connected to the back of the metal box. There were 3 neutrals, that were all connected together and fastened in a plastic clip.

I didn't take note of the original connections although I'm not sure where I need to connect now as I'm puzzled.

Help please.

 

[JohnW2]

I took off the switch in a bedroom to replace it with a dimmer switch. When I removed the switch (after turning off the supply) I noticed that there were 3 lives wires.

How did you know they were all 'live'. Do you mean that there were three brown (or red) wires connected to the switch, or what?

The earth was connected to the back of the metal box. There were 3 neutrals, that were all connected together and fastened in a plastic clip.

Again, how do you know they were neutrals - do you mean that they were blue (or black)?

I didn't take note of the original connections ...

Foolish I'm amazed by how many people make that mistake - particularly in these days of ubiquitous camera-phones and digital cameras!

Is there a second switch which controls the same light(s) as this switch?

Kind Regards, John

 

[Anticmosquito]

Yes all three browns (no extra sleeves) and three blues (no extra sleeves) photo attached[/img]

 

[Anticmosquito]

//www.diynot.com/network/Anticmosquito/albums/

 

[JohnW2]

//www.diynot.com/network/Anticmosquito/albums/

Untitled

• Anticmosquito
• 7 Sep 2014
• 1

Kind Regards, John

 

[Anticmosquito]

Sussed it, trial and error! Thanks for you help though

 

[JohnW2]

Sussed it, trial and error! Thanks for you help though

Glad to hear that you've goit the desired result - although I could never recommend, or even approve of, 'trial and error' - in many situations (albeit probably unlikely with light switches) it can result in disaster!

If those three browns haven't been bent around very much since having been removed from the old switch, I think their positions, as in the photo, probably gives a very good clue as to how they probably should be connected to the new switch (top one to COM, or whatever, and the other two to L1 and L2, or whatever they are labelled).

Kind Regards, John

 

[plugwash]

Seems more likely to me that it's a one way setup and he has incoming permanent live, outgoing permanent live and switched live.

 

[sparkwright]

Seems more likely to me that it's a one way setup and he has incoming permanent live, outgoing permanent live and switched live.

Exactly.

 

[JohnW2]

Seems more likely to me that it's a one way setup and he has incoming permanent live, outgoing permanent live and switched live.

That's a possibility but, if so, to get everything (including other lights) to work correctly, he would have to have put two (and the right two) of the browns into one terminal of the dimmer - which I would not have thought would be a particularly obvious part of a 'trial and error' process.

Anticmosquito:Is that what you have done, or did you put each of the browns into a different terminal of the switch? Is everything (including other lights) working normally?

Kind Regards, John

 

[Anticmosquito]

I put two browns into the C terminal and the remaining one in L1.

 

[JohnW2]

I put two browns into the C terminal and the remaining one in L1.

Ah, they were right, then! - and you obviously chose the right two browns to put into the C terminal (the two at the bottom of your picture, I imagine?). As a matter of interest, did you just guess (as part of your trial and error process) that two had to go into the same terminal, or did you remember that from the original switch?

Kind Regards, John

 

[Anticmosquito]

I seem to remember there being two cables in one of the terminals on the original as both had the connectors up. Other than that, it was trying which combination worked in the correct way without affecting the rest of the circuit.

 

[JohnW2]

I seem to remember there being two cables in one of the terminals on the original as both had the connectors up. Other than that, it was trying which combination worked in the correct way without affecting the rest of the circuit.

Fair enough (not that I can really condone 'trial and error' ).

Kind Regards, John

 

[ban-all-sheds]

Sussed it, trial and error!

It's hard to imagine a more foolhardy way to do electrical installation work.

Please don't try it again - next time it could be the last thing you ever try.

The only acceptable basis for working on your electrics is a full and genuine understanding of what you are doing, and why, and how it all works.