derating dimmers for mains halogen - electricians help please

happyhero

Can anyone help please does this switch need derating for mains halogen fittings

http://www.tlc-direct.co.uk/Main_Index/Wiring_Accessories_Menu_Index/White_Mk_Accessories/Wiring_Accessories~Dimmers_4/index.html

I know they sell it cheaper on screwfix but it didn't give much information hence the link.

I know normally you derate dimmers to roughly half for GU10's but what about this one? I know that some do not need to be derated. Any link to details about this dimmer not needing dimming would be appreciated.

espresso

Download the TECHNICAL DATA SHEET.pdf from here

happyhero

espresso wrote: »

Download the TECHNICAL DATA SHEET.pdf from here

Hi thanks for your answer but I did look at this and it mentions low voltage and other lamps but doesn't seem to explain weather you need to derate for GU10's (mains halogens) or not.

Sorry if I am being dumb and missing it but I can't find anything on this.

Or does this bit (from the pdf file) tell me in some way that I do not understand

Start feature is also particularly beneficial when used to dim Mains Voltage Tungsten Halogen lamps which have inherent very high inrush current at switch on.

If this is the important part could you explain some more please?

Alan50

Please hire an electrician to do this work, overheating of equipment can cause a fire/shock situation.

Kind Regards

Alan (NICEIC domestic electrical installer)

see https://www.NICEIC.com for advice

happyhero

I used to be in building maintenance but now retired. Have some electrical qualifications (16th edition etc) ( no not part P) and so feel quite able to tackle this. I worked in industrial buildings so have less experience of dimmers, but have the intelligence to know what to do and not to do. What ever I do I would like to understand about this dimmer.

If I remember right, were the dimmers not derated for GU10's mainly because they drew a high current on start up and was that not virtually the only reason you had to derate. If this is correct then I assume the sentence in the pdf tells me this dimmer does not have to be derated, but I would just like someone to clarify it for me, please.

baldelectrician

Some dimmers reqire derating, some don't.

If it doesn't make sure the lamps ar decent- to paraphrase, it says on some MK dimmers 'no derating required - if you use craap lamps and it blows the dimmer up don't call us'

I would suggest osram or phillips lamps.