wiring halogen lightsto plug socket

[harry1001]

Hi

I have a set of halogen downlights that I want to wire to a plug socket via a dimmer switch. The lights are linked to a dimmable transformer that has a live and neutral input and output. The dimmer switch has a L1, L2, and wiggly line (line out I think) and I have 2 core wire an standard 3amp plug.

Is it possible to wire the transformer to a plug socket via the dimmer switch? If so where do the neutral wires connect from the plug to the switch and switch to transformer?

Thanks

 

[sparkwright]

You would connect the two neutrals together in a connector block within the switch box.

Alternatively, keep the cable continious, break into the cable sheath where the switch is, but only cut the live wire, not the neutral.

Work safely.

 

[harry1001]

Thanks

I've tried the connector block and it doesn't work. The dimmer switch is one for use with low voltage transformers.

I think the transformer might have failed. How long do they usually last? I can hear the dimmer switch buzzing but no noise from the transformer?

 

[Taylortwocities]

Live in from the plug goes to the wiggly line
Live out to the transformer goes to L1.
As above. The neutral from the plug and the neutral out to the tranny connect together in a separate connection (eg a bit of choc block).

Meerkat

• Taylortwocities
• 11 Dec 2009
• 53

Simples!

 

[sparkwright]

You say you think the transformer may have failed. May be easier to confirm if the dimmer switch is ok first. To do this, disconnect dimmer and place the two lives in another connector block, then plug in.

Or, if you know the dimmer is definitely ok, find a known work light fitting and temporarily connect that up.

Are you using all new fittings, or is this made up of old bits and pieces you've salvaged?

 

[ericmark]

Using a dimmer to feed a transformer is dependent on the dimmer being designed for the inrush of the transformer however extra low voltage tungsten lamps don't today normally use simple transformers but use switch mode power supplies.

Some switch mode power supplies are designed to be used with dimmers although since the whole idea is to maintain the voltage to within very close limits as both under and over voltage will reduce the life of a quartz bulb it does rather seem silly to dim a quartz bulb.

The switch mode power supplies that can be dimmed are split into two groups leading and lagging and the dimmer must be of the same type. Also the coiled coil within the quartz halogen lamp can effect the way it works because of the high frequencies involved.

So although sometimes makes of bulb, inverter and dimmer can be mixed to be sure it will all work inverter, dimmer and bulb should all be same make or odd flicker and pulsing can occur.

There are two reasons for using extra low voltage one is for safety in wet areas like bathrooms the other is when used with no dimmer the inverter will extend bulb life but as well as a maximum current many inverters also have a minimum current which stops the use of Cold Cathode and LED lamps as a direct replacement so there has been a move to using GU10 lamps which are in the main low voltage (230vac) so don't need a transformer.

How all this is considered as simple I don't know? Unfortunately adverts are misleading with extra low voltage items being incorrectly marked as low voltage and with inverters being marked up as transformers. They do have a transformer inside but also have a load of electronics as well.

So big questions are:-
1) Why do you want extra low voltage (ELV) 12v?
2) Why use quartz envelopes if you want to dim the lights? Quartz is not suitable for dimming.

 

[PrenticeBoyofDerry]

Hi

I have a set of halogen downlights

How many and what is the combined load?

The dimmer switch has a L1, L2, and wiggly line (line out I think)

And is rated at?

 

[harry1001]

Hi

I have 5 x 20w down lights with a 105W/VA transformer. The dimmer switch is rated at to 400w and has a sticker on it saying min 60w with following info on the packet

Use with most electronic, toroidal transformers and tungsten lamps.
No de-rating required. Resistive and inductive loads compatible. Integrated over-temperature protection fuse.

I'm using these lights as this is what I've got spare. The MR11 halogen bulbs also say dimmer compatible.

 

[sparkwright]

So have you narrowed down the fault yet?

 

[harry1001]

I think I have. I tested the lights directly (without the dimmer as suggested) and still no light so i'm going to try a new transformer and see what happens....

Thanks

 

[ban-all-sheds]

The MR11 halogen bulbs also say dimmer compatible.

Of course they do - the manufacturers like it if you make them last less time by dimming them, that way they get to sell more.