Dimmer problem

[Albert]

Hi, Happy Christmas and a happy new year!

An old 3 gang dimmer switch has a problem that one of the dimmers stops working, out of 3 only one goes. they are all the same, I change all 3 a week ago and had to change one of them already twice. It does not seem to burne out or at least there is no visual damage. it is connected to 6 x 50W ELV downlights and it is 2 way with another 3 gang identical dimmer (I already told the customer that this is not a working configuration but she insists to leave it as is) . The new dimmers are 400W 2 way. I looked for 600W to fit in but it is too big for a 3 gange unit.
Any suggestions?
Thanks

 

[Lectrician]

Dimmers shouldn't be connected two way. I would fit a 3 module MK grid assembly with dimmers/switches as appropriate.

Have you checked the transformers are dimmable, and if they are leading or trailing edge, and they are compatible with the dimmer you are fitting? You have 300watt of light, with out applying the derating factors of ELV lights and trannies.

 

[Albert]

Thanks for the reply.

This configuration existed for several years (this was my first visit to this site), the first thing I said to the customer was that this is not a workable configuration, she insisted to keep it as is because it looks nice (I mentioned this in my previous post).

I know that the load will be about 300x1.8, I could not find a 600W small enough to fit in the existing 3 gange dimmer switch. I am going to change again the component, I put in a 400W beliving that it is for low voltage, I going to get another one and make sure that it is for low voltage.

As the dimmers worked not as a 2 way but when one of them was full on the other worked as a 1 way dimmer, so I assume that the rest of the installation is ok.

If it will damage the next component, ofcourse I will have to check all the other parts of the circuit.

 

[securespark]

If the only reason to have 2 dimmers is because "it looks nice", then put three of these in instead:

They look like dimmer modules, but are switches only.

As for the dimmers not working, insist that you can only guarantee the dimmers you install if they are installed correctly, ie only one on each light.


If she refuses, I would refuse to keep coming back & replacing them.

Only when the dimmers are correctly installed can you see if the problem resolves itself. In other words, if you limit each light to having one dimmer, and they still stop working, then you know the problem is elsewhere. However, if, once they are correctly installed they keep working, then you are OK.

But what was said earlier about the dimmer being the right one for the load is sound advice.

If the dimmers are not intended to switch TH loads, you'll need to derate.

 

[Albert]

Yep, you are right, but you know how it is, they say "but it worked fine before" how can I argue I was not there...and I must give some credit to my customers...

The dummy dimmer switch is a great idea, where can I find them or how is it called? I understand that they can be 1 or 2 way and will fit in a 3 gange dimmer switch.

 

[Taylortwocities]

http://www.tlc-direct.co.uk/Products/VLSM.html

 

[Albert]

Many thanks

 

[ban-all-sheds]

Nothing wrong with 2-way dimming, as long as the dimmer modules are the sort that are actually 2-way switches, one output just switched, and the other dimmed.

As long as you don't mind not always being able to control the dimming from the location where you just turned the light on...

 

[Albert]

I agree with you, when I said that this is the unworkable configuration I meant it will not work as a full dimmer in both sides. I know that from safety point of view this is not a problem.

The modules definitely are 2 way.

As the customer is aware of this configuration problem and uses only one side for dimming, I think that I will go for the dummy dimmer module.