Help on 2-way Switching with Dimmer required

[dev007]

Hello All,
I am looking for some guidance and help on a the following setup:
In my lounge, consists 2 ceiling lamps of 5*40W G9 bulbs.
They are currently setup and working by a 2 Gang, 2-Way using standard switches.
1. Is it possible to change only 1 2 Gang switch into a 2 Gang Dimmer type? or do I have to change both 2 Gang switches into 2 Gang Dimmers.
2. If I can change one of the 2 Gang Switches to a 2 Gang Dimmer, which type (any special requirements) and what rating would I purchase.
3. If I can change both 2 Gang Switches to 2 Gang Dimmers, then what type (any special requirements) and what rating would I purchase.

Thank You in advance...Dev

 

[Spark123]

The most basic way is to replace just the 2 gang switch with a normal 2 gang 2 way dimmer. As a rule of thumb you need to derate the dimmer by half as the load is halogen so a 400w dimmer each way is required unless you source one which says it doesn't need to be derated.
With a normal 2 way dimmer switch you can only have a dimmer at one location, the other switch must be a normal 2 way switch.

It is possible to dim from more than one location using master slave units (also depends on your existing wiring), take a look at http://www.tlc-direct.co.uk/Main_In...s_All/Wiring_Accessories~Dimmers_5/index.html

 

[dev007]

Thanks Spark123

So to summarise;
If I change 1 of the 2 Gang switches, get a 400W rated Dimmer.
If I decide to change both of the 2 Gang switches, then I have to adopt the master/slave option...so what rating would I choose then? ...400W each or a compound to 400W?

 

[flameport]

The 'IQ' dimmers including the remote/s;ave ones linked to earlier don't need to be derated (so a 400W dimmer can be used with 400W of lamps).

Even if you don't get the slave/remote ones it is still well worth it to use the IQ dimmers as they have a soft start - your lamps will last MUCH longer.

 

[dev007]

Now, I am confused or I have mis-informed..in my earlier post:
I have created a small very quick diagram to aid.
I definitely need to change Sw1 to a dimmable as the wall lights are controlled from that switch set only....What ratings do I require considering the lamps connected (confused by each switch setting or are all switch ratings the same).
Also, I am in 2 minds about changing Sw2...again what switch ratings do I require, bear in mind the landing light & porch light is not required dimmable.

I appreciate all the help you chaps/gals are giving me and the rest of the less knowledgeable users of this forum, keep up the excellent work.

Regards,
Dev View media item 10535

 

[Spark123]

Yep - you failed to mention the 160w of wall lights
The big question is, do you want to be able to dim the two ceiling lights from more than one position or are you happy to just put up with dimming them from Sw1 position? I don't think you can get single patress 3x dimmers so you will probably have to put a double one in.
Something like this should do you if you only want to dim from SW1 position: http://www.tlc-direct.co.uk/Products/VLQP303.html

 

[dev007]

Hello Spark123, surprisingly, correct on a few accounts, Sw1 is on single plate, planning to open up and fit a double. I did not mention the wall lamps earlier as to avoid total confusion without a diagram...on purpose.
So, if I replace Sw1 only as described by yourself, the 3*300W will suffice.
If I decided to change both Sw1 & Sw2 at the same time I now know that I would have to adopt the Master/Slave option, but how would that affect the ratings of each switch? ie would I get a 3*300W and a 4*300W (just assume, all lights are dimmable for simplicity) ?
Many Thanks

 

[Spark123]

It isn't quite as simple as that, the slave dimmers are just that - they don't do the work of the dimmer hence don't have a rating, that is the job of the master. You have one master dimmer and as many slaves as the master will permit.
It is possible but a bit messy as you will need to have 3x master dimmers at Sw1 then 2x slaves and 2 x normal switches (for the porch and hallway) in a dual patress at Sw2.

As the normal type one I linked to above is suitable for halogen it doesn't need de-rated