Dimmers for two way switching

[The Medway Handyman]

Will a normal dimmer switch work on a two way circuit? e.g. 3 core & earth.

[John Kenyon]

It depends on the dimmer switch. If it only has two terminals for supply/load, then the answer is no.

/john

[Andy Hall]

Yes, provided that it has a two way switch arrangement as well.

Some have this by alterately pressing the knob of the switch, for example.

Obviously the dimming function will only be available for one end.

If you want something that does that, then it is likely to be the province of one of the home automation sites which sell more sophisticated lighting controller systems.

[Lurch]

On Sat, 10 Mar 2007 20:54:17 GMT, "The Medway Handyman" mused:

Define 'normal'.

If by normal you mean '2 way', then yes. If by normal you mean '1 way' then no.

[Harry Bloomfield]

Lurch presented the following explanation :

It could be done by making the dimmer an extra switch position, in circuit after the two way circuit, in other words - in the switch wire to the light(s). That would provide lighting level control providing the circuit was turned on first at one of the 2 way switches first.

[Lurch]

On Sat, 10 Mar 2007 21:18:20 GMT, Harry Bloomfield mused:

That goes down as a bodge in my book. Far easier to just use a 2 way dimmer, which does what you describe but in 1 unit.

[John Rumm]

Yup. If you want to dim for both ends however then you need a master / slave dimmer set (see TLC). You can have many slaves to a master as well if required.

[Jason]

In general, yes. But unless it is a master-slave arrangement, then you could be in the position that you can turn the light on and off from two or more locations, but you always need to go back to the dimmer end to turn the light up.

The only master-slave versions I've seen in the past, tended to be push-button dimmers with the dimming circuit located up in the ceiling. You could push up/down once to turn fulling up or fulling down, or hold the buttons to cycle through the dimming range. These were used on flourescent tubes and worked really well - on and off was always through a soft fade up/down cycle.

-- JJ

[Andy Dingley]

Define "normal". Older ones wouldn't, the current production ones do (and are labelled as such).

OTOH, modern dimmers seem to have negligible resistance to peak currents during bulb failures killing them 8-(

[stevelup]

Hi

Have a look at the Varilight IQ touch dimmer range from TLC. They are not much more expensive than a decent rotary dimmer and will do exactly as you wish.

Regards,

Steve