installation of a double dimmer

bibi-phoque

I thought it would be a good idea to ask first before messing up everything!

Basically, we have 2 lights in the living room, and there is a double switch in both side of the room. What I would like to do is replace one of this double switch by a double dimmer. Is it straight forward? Something I realized recently is that there are 2 blue wires going to the bulbs and I know that if they are not connected together then the light in the kitchen doesn't. So it looks like they are all on the same circuit.

If I replace one double switch with a double dimmer, is there any special consideration knowing that there is another switch at the other side of the room? Also, with the kitchen on the same circuit, will the dimmer have a effect on the kitchen light too?

M cebee

the only snag is when you 2-way from the standard switch it wont always be full brightness

bibi-phoque

M cebee wrote: »

the only snag is when you 2-way from the standard switch it wont always be full brightness

Why not? If the dimmer is set to maximum, I don't understand why it wouldn't be full brightness if I use the other switch to turn on/off the light.

M cebee

exactly:)-if the dimmer is set to maximum

the other 2-way will function as before

ntpm

Usually straight forward swap out.
Just check the wiring diagram supplied by manufacturer. (Some switches state different connections to use is the dimmer is the first switch or second switch).
Leave any "loop" neutrals as they are.

As stated the only inconvienience is is the dimmer has been turned down and the light may not always be at full power when switched on.

2011

There are a few things that you need to take into consideration:

1) Are the lights that you intend to dim suitable for dimming? For example some down lighters have transformers that are non dimmable. Also many fluorescent lights can not be dimmed.

2) Is the dimmer switch suitably rated?? Example: You should not use a 250VA dimmer on 300 Watts of lighting

3) Is the switch box deep enough? Dimmer switches generally require a far deeper box than standard light switches.

4) If the dimmer requires an earth, have you got one and can you confirm that it is connected?

5) There are many cheap dimmers out there that simply don't work, buzz or fail quickly. MK for example are very good, but they are expensive.

Just a few thoughts....

cast_iron

You can always replace both switches with dimmers and have full control at both switches. This would eliminate the problem of needing to go to the dimmer switch each time more/less light is needed.

2011

You can always replace both switches with dimmers and have full control at both switches

This will not work with standard dimmers. Look at the wiring diagram for 2 way switching. The result would be 2 dimmers in series with each light.

cast_iron

2011 wrote: »

This will not work with standard dimmers. Look at the wiring diagram for 2 way switching. The result would be 2 dimmers in series with each light.

Yes, but they are designed to work that way are they not? I've certainly seen the standard ones work on 2-way without any issue.

2011

Yes, but they are designed to work that way are they not?

With 2 way switching it is only possible to have a dimmer at 1 end. If this is not done the there will always be 2 dimmers in series with the light i.e. one dimmer feeding the other.

cast_iron

2011 wrote: »

With 2 way switching it is only possible to have a dimmer at 1 end. If this is not done the there will always be 2 dimmers in series with the light i.e. one dimmer feeding the other.

We'll have to agree to disagree on that one. You're quiet right in what you say about the 2 dimmers being in series....but I've seen it work without any noticeable problems.
Thinking about it...perhaps it's the 40watt (typically) min wattage required for the dimmer to operate that prevents one dimmer killing the other altogether.

M cebee

i doubt you can have a dimmer both ends

never tried it or thought about it much

meercat

agree with m cebee and 2011
dimmer on 1 end only
otherwise you may never get light to illuminate fully without turning both dimmers up fully
pointless exercise fitting 2 dimmers

Bruthal

cast_iron wrote: »

We'll have to agree to disagree on that one. You're quiet right in what you say about the 2 dimmers being in series....but I've seen it work without any noticeable problems.
Thinking about it...perhaps it's the 40watt (typically) min wattage required for the dimmer to operate that prevents one dimmer killing the other altogether.

Well i think its pointless anyway having them on both ends, and 2011 surely is right,

If you turn off a dimmer on one end while its at 50% brightness and go to the other end and switch over the normal 2 way you still have 50% brightness when the light comes on. So how can having a second dimmer at this end possibly now bring on full brightness? At best it can again only get 50% brightness with the second dimmer full on while the first is at 50%. So why have them both ends?

paddy147

I have a dimmer switch/panel at both ends of my living room.


Works a treat too.:)

Bruthal

meercat wrote: »

agree with m cebee and 2011
dimmer on 1 end only
otherwise you may never get light to illuminate fully without turning both dimmers up fully
pointless exercise fitting 2 dimmers

You beat me too it:)

ntpm

If can fit two dimmers in series but they must be wired through two way dimmers connections.

You can not normally power the transformer coils in series.

Basic two way set up is assumed...

Switch one:
Live in = C
Transformer coil = L1
Switch over contact = L2

Switch Two:
Live Out to light)= C
Transformer coil = L1
Switch over contact = L2


Loop from Switch 1 Terminal L1 to Switch 2 Terminal L2
Loop from Switch 1 Terminal L2 to Switch 2 Terminal L1

As shown above the coils are not in series but only one dimmer will actually dim depending on which one is switching.... not practical.

The above is just a schematic connection/ numbering will depend on manufacturer.

Some manufactures will allow both dimmers to dim at the same time.

Bruthal

paddy147 wrote: »

I have a dimmer switch/panel at both ends of my living room.


Works a treat too.:)

But why bother? Switches at both ends are to enable lighting of a room so you dont have to walk to the other end in darkness when there is 2 entrances. Surely a dimmer at one end is good enough. If you want full brightness you may need to go to both ends to turn up fully.

Seems a pointless setup.

M cebee

cast_iron wrote: »

You can always replace both switches with dimmers and have full control at both switches. This would eliminate the problem of needing to go to the dimmer switch each time more/less light is needed.

ok guys :pac:

so does this work or not

even i'm getting confused now with all these 'google electricians':D on the forum

cast_iron

meercat wrote: »

agree with m cebee and 2011
dimmer on 1 end only
otherwise you may never get light to illuminate fully without turning both dimmers up fully
pointless exercise fitting 2 dimmers

Like I said (and I'm not fully sure why or how:)) it works ok without any noticeable problems.
I'll have a tinker with this later this week as I know someone with it done. It works a treat for them (maybe I know Paddy )

Intermediate switching is possible too as far as I'm aware, though a special unit is required at said switch.

Bruthal

M cebee wrote: »

ok guys :pac:

so does this work or not

even i'm getting confused now with all these 'google electricians':D on the forum

It would work if you are turning the dimmer all the way to full brightness before it clicks off. But i cant see it working if you are pressing in the dimmer control button to turn it off in its present position as this would just change the dimmed switch from L1 to L2 but still have this dimmed value in the circuit when the other switch is operated.

Bruthal

ntpm wrote: »

If can fit two dimmers in series but they must be wired through two way dimmers connections.

You can not normally power the transformer coils in series.

Basic two way set up is assumed...

Switch one:
Live in = C
Transformer coil = L1
Switch over contact = L2

Switch Two:
Live Out to light)= C
Transformer coil = L1
Switch over contact = L2


Loop from Switch 1 Terminal L1 to Switch 2 Terminal L2
Loop from Switch 1 Terminal L2 to Switch 2 Terminal L1

As shown above the coils are not in series but only one dimmer will actually dim depending on which one is switching.... not practical.

Is that how they work? If you used L2 for 1 way switching then the dimmer would not dim the light, only L1 does the dimming?
I assumed you are switching the dimmed internals of the switch between L1 and L2. I have had little to do with dimmers all the same down the years.

cast_iron

M cebee wrote: »

ok guys :pac:

so does this work or not

even i'm getting confused now with all these 'google electricians':D on the forum

As far as I can see, ntpm's setup seems to say it's perfectly possible...though I can read things wrongly at times.:)

I'm not basing anything I write on 'google' - purely on what I've seen out in the field.

Bruthal

M cebee wrote: »

ok guys :pac:

so does this work or not

even i'm getting confused now with all these 'google electricians':D on the forum

Ye did`t think i was a real sparks did ye.

Bruthal

cast_iron wrote: »

...though I can read things wrongly at times.:)

Tell me about it, im doing it on an hourly basis these days, it used to be weekly at worst:)

cast_iron

robbie7730 wrote: »

Tell me about it, im doing it on an hourly basis these days, it used to be weekly at worst:)

Working too hard:pac:

Seriously though, I did scratch my head when I seen it in operation as it doesn't make alot of sense at initial glance, and both switches seemed to work up to full power. ntpm may have solved the mystery. The switches were a 3-way Aurora (someone can google that if they like:p)

Having 2-way at both switches just gives double the choice in where to dim...no real advantage after that.

ntpm

Robbie 7730:

As far as i am aware this is how I wired them.....
have always refered to manufactures info at the time... can't remember exact terminal connection.
Memory not too good.... age is suspect.

Bruthal

cast_iron wrote: »

As far as I can see, ntpm's setup seems to say it's perfectly possible

Its still seems pointless though, because if the dimmer does work like this, i think you will be switching the dimming capability from one end of the livin room to the other. And if the dimmer does work like this then a 2 way dimmer at one end and standard 2 way at other then the dimmer would only work when the standard 2 way is in a certain position.

Bruthal

ntpm wrote: »

Robbie 7730:

As far as i am aware this is how I wired them.....
have always refered to manufactures info at the time... can't remember exact terminal connection.
Memory not too good.... age is suspect.

yea im not saying your wrong at all, i just assumed they did switch the dimmed circuit between the 2 contacts L1 and L2, otherwise it would not be possible to dim the lights with the standard 2 way at other end in one of its positions.

Bruthal

cast_iron wrote: »

Working too hard:pac:

Seriously though, I did scratch my head when I seen it in operation as it doesn't make alot of sense at initial glance, and both switches seemed to work up to full power. ntpm may have solved the mystery. The switches were a 3-way Aurora (someone can google that if they like:p)

Having 2-way at both switches just gives double the choice in where to dim...no real advantage after that.

Yes but if the dimmers work how ntpm says, which i am not saying they dont, then you cant dim them freely from each end, and he says that in his post,

cast_iron

robbie7730 wrote: »

Its still seems pointless though, because if the dimmer does work like this, i think you will be switching the dimming capability from one end of the livin room to the other. And if the dimmer does work like this then a 2 way dimmer at one end and standard 2 way at other then the dimmer would only work when the standard 2 way is in a certain position.

I can't argue with you there.