Two dimmers in series?

[Robin]

Would halogen lamps work safely with 2 dimmers in series please? Even if (by mistake) both dimmers were set below max?

Background is elderly lady moving into care home. No space for her to take all her current uplighters, spotlights etc. She likes uplighter with dimmer. And she needs spotlight for reading. She also needs switch on table within reach.

Best option I've come up with is a "mother-and-child" floorstanding lamp with halogen lamps[1]. But the ones I've seen which are robust enough[2] come with dimmer switches built in. I'd need to add an in-line dimmer to put on her table. But I don't want to have to by-pass the switches in the lamp in case she wants sometimes to have uplighter without spotlight or vice-versa. Trouble is I've forgotten what little electronics I ever crammed so I can't fathom the risks.

[1] we'll face the ending of halogen G9s if she lives to see it [2] I know any floorstanding light can be toppled but her current uplighters survive her treating them as occasional grab rails ;)

[Tim Watts]

No.

The first dimmer would produce a choipped waveform that would almost certainly bugger up the second dimmer. These are not simple variable resistors.

Your best bet would be to replace the dimmer on the wall with one that can take a remote control (pretty common). Have no dimmer in the floor lamp.

[Robin]

FWIW the plan was to have no light, dimmer etc on the wall. Just one floorstanding light such as

with one dimmer switch on the table beside her.

[Mike Clarke]

In theory I'd agree with you but recent experience suggests otherwise.

The house my daughter moved into last year had the staircase light fed through a couple of conventional cheapo 2 way dimmers. They worked in so far as it was possible to dim the light.

But from the convenience point of view it was a seriously bad idea because you couldn't switch on a decent level of illumination if the dimmer at the other end had been left turned down low. Even a single dimmer for the only light on a staircase was a pretty dumb idea. We didn't waste much time replacing them with ordinary 2 way switches.

[John Rumm]

The way to do dimmed lighting controlled from two places is with an electronic master/slave set of dimmers. You wire them the same as a two way system, have one master dimmer and then as many slave dimmers as you want (within reason). You then have full range brightness control available from all switch positions.

[David]

Ferry interesting....

.....do you have a link to these slave dimmer switches?

Having wired up the living area with a dimmer and a dummy dimmer which is just a push switch it would be nice to be able to dim the lights from both switch panels. :-)

Cheers

Dave R

[Tim Watts]

Well, you might get away with it - but there is no way that is a design that should ever be implemented!

What you don't know is how much stress the borked waveform is casuing the second unit and whether the 2nd unit might see fit to go up in smoke.

You can get dimmers with (momentary or rotary) remote inputs.

In fact I am warming to the idea of remote dimmer modules mounted somewhere fire resistant and just having the remote switches on the wall.

[Tim Watts]

GET make some - but these are leading edge so dimming LEDs is hit and miss.

There are some other makes that do trailing edge and one particular brand does dull remote modules (bit like SELV PSUs) where every switch is a "remote" as in the main current goes into the module and straight out into the lamp and not via the switches.

[Brian-Gaff]

Last time I tried two dimmers it just produced wandering light levels, and a lot of hysteresis where nothing happend at all ove much of the travel of one of them. After all you are affecting the waveforma and hence the duty cycle and all sorts of strange stuff could happen. Brian

[John Rumm]

Yup, TLC have them: