Swapping a switch for a dimmer

[johnsimpson]

Hi all,

I am looking for a little advice please,

We have just put some new lights up in our kitchen / dinner and we want to install a dimmer to be able to control the brightness...

I took the current switch off which has 2 switches to replace with a dimmer I bought from screwfix.

I wired the dimmer up identically to how the existing switch is but the lights won't work...

Please see the example of how my existing switch is configured



In case you can't make it out the neutral wires are all joined together and are not in the switch at all and the live wires are connected to L1 and L2, it also has a seperate wire going from L1 to L1

and here is my new dimmer switch



Now I have also just read about the rating on the dimmer, the dimmer I have is for a maximum load of 400W, my light in the dinning room has 6 x 60W G9 bulbs and the light in the kitchen has 4 X 60W G9 bulbs... is the dimmer suitable for this or is that my problem?

I hope you can help

thanks

John

 

[Technician]

Can you place a picture showing how

you have wired up the new switches?

The first picture shows two two ways

with terminals made common.

 

[johnsimpson]

Sorry, I didn't take a picture of the new dimmer configuration, I may be able to this afternoon but essentially it was identical, if you look at photo 1 there are 3 Main brown wires coming from the mains wiring, it has 1 wire into L1 and the other 2 wires into each L2 port, then we have a new piece of wire joining the two L1 ports... I just copied this configuration exactly over to the dimmer... does that make sense?

 

[samson337]

It looks like you have two switches, one for each set of light ? L1 looks like your main feed in and is bridged to L1 for the second switch and L2 being your switch wires, so just connect the dimmer the same way. So L1 on your old switch will go in Com, dont for get to bridge the com on the new switch and the switch wires will go in L1 on your new switch

 

[Revved Up Sparky]

Like Samson said, put the wire that was in L1 (the permanent live) into one of the terminals marked C and put a piece of wire between that C and the other C, then connect each outgoing switchwire to each of the L1 terminals. A common error is to get the wires mixed up, in which case you may need to acquire a voltage tester or get hold of a competent electrician to test the wires for you.

 

[johnsimpson]

yes there are 2 switches, one for the kitchen and one for the dinning room...

Sorry just to make this clear I should put the wires from the L1 port on the current switch into the port marked C on the dimmer (including the single seperate wire to go from C to C?) and the wires from the L2 on the current switch into the ports marked L1 on the dimmer?

Just another question before I try this, what will happen if anything is wired up wrong? will it merely not work or at worst trip the fuses out?

---------- Post Auto-Merged at 11:23 ---------- Previous post was made at 11:22 ----------

sorry just seen your reply revved up, I think this makes sense thank you all for your advice, I will give it a try at lunch and let you know how I get on...

 

[NozSpark]

The wires that were in the L1's of the old switch go into the C's of the new

The old L2's can go into either the L1's or L2's,,, it usually won't matter

 

[johnsimpson]

Thanks guys, just tested this now and worked great! only problem now is that the back plate is too small so I have put the original switch back on and I will nip to the shops soon to get a new back plate!!

thanks again for all your help!

John

 

[samson337]

Glad you got it sorted

 

[SLIPSHOD & SLAPDASH]

Number each cable and take a pic before you change the box

 

[johnsimpson]

Already done that slipshod, before I took the wires off last time I put bits of tape around them and took a pic anyway to make sure I was 100% sure but I will double check and make sure there is no room for error, just been and bought the box but have a bit of work to do right now so I will be installing it later this afternoon... I will let you know how I get on,

thanks again guys, huge help!

 

[SLIPSHOD & SLAPDASH]

Probably too late now, although the switch will fit in a 25mm deep box i always fit 35mm. Dont forget the rubber grommets where the cable enters the box.

 

[rob-uk]

The wires that go to L1 on the old switch need to go to C (common) on the dimmers and the wires that go to L2 on the old switch go to L1 on the dimmer. The load should be fine as well.

 

[johnsimpson]

I have fit the new box and it's all working ok now, I had a minor issue when I turned electric on nothing worked so took it all to pieces again and I think it may have been the earth, one if the switches in the fuse box had tripped so after checking it all and turning on again all ok!

I didn't put a gromit on tho, the wires had rubber sleeve around but maybe I should take to bits and put one on do you think?

Also when I was taking the old box out its knocked a load of plaster out, what's the best tricks for filling? It looks like the builders used caulk or something like that, should I do the same and the polyfiller over? Or is it better to build up filler in layers?

Again thank you guys

 

[SLIPSHOD & SLAPDASH]

Throw a bit of white filler in, i prefer Tetrion. If the holes are deep finish the first layer below the surface and then finish with a smoother thin skim over the top once the first layer has dried