Halogen Light Dimming

[Total_Novice]

Hi there,

My first post on this forum. Here goes.

I've had a light from Next in my bedroom for some time, and want to install a dimmer for it. On the box, it says its compatible with Halogen Specific Dimmers.

Specs from the web site are below:

Metropolitan 10 Light Suspension Fitting
Contemporary chrome finish with clear frosted glass shades. Mains voltage fitting. 10 x 12v 10w G4 halogen bulbs (included). Halogen is an efficient source of light using small compact bulbs. It provides a bright, clear light and is ideal for reading and working. A 20 watt halogen bulb provides approximately the same amount of light as a regular 60 watt bulb and lasts approx. twice as long. All halogen lights are supplied with bulbs. Fittings must be installed in accordance with Part P of the Building Regulations.
H44 x W67 x D67cm.


What should I be using? Help please!

Cheers

 

[ban-all-sheds]

You need a dimmer suitable for extra-low voltage lighting transformers (sometimes erroneously called "low voltage" by manufacturers who should know better), that is capable of supporting a 100W load. When looking at them, check the small print to verify that their headline rating also applies to 12V transformers.

You also need to find out (ask the light manufacturer if the instructions don't say) if you need a leading-edge (phase delay) or a trailing-edge (phase cut) dimmer, and get the right match.

 

[Total_Novice]

Thanks very much. In the interim, I've taken the specs to a local electrical wholesaler and said "Dim this".

Not too sure about being able to speak to the light manufacturer though, they're probably Korean or something!

 

[olly_k]

You need a dimmer suitable for extra-low voltage lighting transformers (sometimes erroneously called "low voltage" by manufacturers who should know better), that is capable of supporting a 100W load. When looking at them, check the small print to verify that their headline rating also applies to 12V transformers.

You also need to find out (ask the light manufacturer if the instructions don't say) if you need a leading-edge (phase delay) or a trailing-edge (phase cut) dimmer, and get the right match.

Just out of interest, what is the definition of low voltage and extra low voltage? Who has defined this? To me, 12v is low voltage and 12mV is lower still, but 12uV is extra low voltage!

Regarding dimmers and halogens, is there not strictly speaking an issue with bulb life when dimming?

 

[plugwash]

its the IEE who define it in the uk but the figures are pretty similar.

iirc

ELV is less than 50V AC (and some higher figure DC not sure what off hand)

LV is more than 50V AC and less than 600V AC to ground and less than 1000V AC between any two conductors (again figures for DC are higher)

HV is anything with more than 600V AC to ground or more than 1000V between any two conducors.

 

[ban-all-sheds]

Just out of interest, what is the definition of low voltage and extra low voltage? Who has defined this? To me, 12v is low voltage and 12mV is lower still, but 12uV is extra low voltage!

Low voltage means not exceeding 1000V AC or 1500V DC between conductors or 600V AC or 900V DC between conductors and earth.

Extra-low voltage means not exceeding 50V AC or 120V DC between conductors or to earth.

Defined, I guess, by the IEE and/or CENELEC.

Regarding dimmers and halogens, is there not strictly speaking an issue with bulb life when dimming?

Oh yes.