A formal answer to you question.

BS EN 60432-1:200+A2:2012 is the standard for incandescent lamps.

2.2.1 Mandatory markings requires that lamps are marked with their rated voltage or voltage range [this raises obvious question's which aren't addressed in the standard but let's assume nominal within range], and the rated wattage.

But there's a national departure in the BS version "The rated voltage marking for lamps intended for use on United Kingdom supply voltages may be 240 volts or 240 V." so you need to check the datasheet.

This standard is for domestic and similar general lighting. Specialist lamps will have their own standards. But I think it's particularly interesting on bulb life - I have a reading lamp which needs an incadescent because LED's don't pull enough for the dimmer. As I can no longer buy bulbs at retail I've been getting them of a popular website named after a river in South America - and they don't last two seconds probably rated for 230V. I think I might try using a variac.

Amazon/ebay/Temu are remote selling into the UK and a lot of the products sold do not meet a BS or BS EN standard.  Some may say they are selling poor quality items.  If you are looking for lamps for the home Ikea are quite good quality and units last a fair while.  Another point to note is an incandescent is totally electrical where as an LED is electronic. 

Yeah I'd rather an LED but when you've got a lamp that's got an older dimmer then the electronics need current flow through it - because there's no neutral connection in the dimmer. So unless I do something radical I can only use incandescents - or halogens.

Even if I replaced the dimmer, dimmable LED's operating of mains are just embarrasingly poor - especially for a reading lamp. Maybe I'll wrap some dim to warm tape around a tube and install a driver. But that would probably look very heath robinson.

I can't be the only person with this problem - it's clearly widespread and has been for over a decade - but nobody can find a good solution.

I have used a low wattage transformer for 12-18V as an autotransformer to prolong the filament life in such case - primary on the mains, of course, and the secondary in anti-series (opposition) to the mains, to give mains in less the secondary  voltage.
Its smaller/ easier than the variac, and less heat than the resistor.

Though a resistor may be better in some ways as it actually limits inrush too.

M

Could try and speak to company like JCC and see what they have to offer.  Realistically you need to match the lamp and the dimmer to get the best effect. 

Its not just the lack of neutral - because the LED light power supply starts with a bridge rectifier and a capacitor, the dimmer sees a very odd current waveform, and indeed at the moment the triac firing circuit triggers, there may be no current at all if the cycle has yet to reach a voltage that exceeds the smoothing capacitor voltage so the bridge is not yet conducting. Repeated firing pulses to the SCR do help,  but makes for a very current hungry dimmer - far more then the normal R/C + diac that we normally get that gives one firing spike per half cycle. Changing between leading edge and trailing edge may help, but you still need the dimming device to be turned on and stay on, when there is not yet any load current, and yet to go off at the voltage zero crossing.

In many ways, the cheaper non dimmable  lamps that are a capacitive dropper, plus a few caps in a box, work much better.

Mike

mapj1 said:

Its smaller/ easier than the variac, and less heat than the resistor.

Yeah I was thinking variac simply because I have one under my desk.

hah I detect a fellow traveller.

You don't keep ferric Chloride in a bottle under the sink by any chance? There are similar points on the hardware geekscale to be earnt by having a lathe at home, and the combination of a lathe and mini-mill is a point multiplier.

M

PS I'm teasing and not at all saying that is a bad thing - I can claim a Variac (20A model, from a skip dive) the ferric chloride (and the HCL to spike it when it starts to fade), the lathe and a small bandsaw, as well as 2 scopes, spec an and  VNA and 2 RF sig gens.

mapj1 said:

You don't keep ferric Chloride in a bottle under the sink by any chance?

There's a limit to what my wife lets me keep in the kitchen. But a few things in the fridge which are clearly labeled up as not for eating. I try to minimize harzards at home for obvious reasons.

mapj1 said:

You don't keep ferric Chloride in a bottle under the sink by any chance?

There's a limit to what my wife lets me keep in the kitchen. But a few things in the fridge which are clearly labeled up as not for eating. I try to minimize harzards at home for obvious reasons.