Dimmers and Separate Light Switches

[kai]

Is there a regulation in the 17th edition that states a dimmer must also incorporate a switch in it? In other words a dimmer switch will have to bear all the surges that occur when lamps are switched on.

It makes better sense to have a separate switch alongside the dimmer, so the delicate dimmer mechanism does not have to switch in surge currents, and the dimmer setting can be held at a constant amount, the separate switch being used to turn the lights on and off.

 

[flameport]

No such regulation.

Push on/off dimmers already achieve what you want, they can be switched on or off at any brightness level.

Those with a rotary switch can only be switched on starting at the minimum setting which avoids a surge.

Therefore what would the arrangement of a separate switch and dimmer control achieve?

 

[ericmark]

Ionisation of the gases inside a bulb when it blows have always been a problem for dimming switches. Although a B6 MCB will turn off in less than one half cycle with a 30A load this can still take out the dimmer switch.

Since this does not always happen at switch on or off then even if the dimmer was only put into circuit after initial switch one it would still be likely to fail when a bulb blows due to ionisation.

Turning on and off the power gradually does produce less strain on the filament and I have noted a tungsten bulb on a dimmer does tend to last longer.

However a quartz tungsten bulb should not be used on a dimmer as these rely on a very carefully controlled quartz envelope temperature to reflect the active material back onto the element also the cold resistance is far lower than hot resistance so they put a huge surge onto the components on switch on.

Years ago I had some cine lamps with a bulb save dimmer it was found switching one at half power and allowing lamps to warm up before going to full power extended bulb life. However this did not use a dimmer it was simply a series / parallel switch centre off for the two bulbs.

Today however many of our lamps include electronics to keep the output the same what ever the input voltage between limits. A GU10 LED bulb will typically have a range 150 to 250 volt same with HF florescent and SELV quartz lamps. As a result the dimmer has to talk to the electronics in the lamp to tell it what to do. This means dimmer systems are becoming more and more expensive and also with LED although light output is reduced the colour does not change no longer does the light become red as well as dim. As a result the modern way is to have selectable groups of lights so to get room lighter or darker one switches on more or less lights rather than dim them.

So the era of the lamp dimmer has passed that was a late 20th Century fashion today it's multi-lamps and group switching. I wonder what it will be tomorrow?

I still remember the gas lamp with mantel that was dimable normally fitted to walls rather than ceiling not old enough to remember oil lamps except for the tilly lamp used when camping. As to lime light

But yes you could do it using grid switches so you can select dimmer or on/off switch.

 

[JohnW2]

... a B6 MCB will turn off in less than one half cycle with a 30A load this can still take out the dimmer switch.

That's interesting - where did you find that information?

All of the ('magnetic' part of) operating curves for B6 MCBs I've seen are essentially vertical at 30A, spanning a range of operating times from 0.1 sec (sometimes 0.01 secs) to over 10 secs, which makes it difficult (impossible!) to tell exactly how rapidly a B6 will operate at that current.

Kind Regards, John