wiring LED strips for multiple cupboards

[jayjay]

I have 5 cupboards along one side of a long corridor, Each cupboard has two doors opening outwards (just like a wardrobe). I would like each cupboard illuminated automatically when the doors are opened by two strips of LEDs (approx 1.5 meters each) down the back of where the doors are hinged. I have a lighting circuit running along the cupboards. How is it best to set up?

1) one isolation switch on 240v supply to all cupboards, then two LED strips, a transformer and a door switch on each cupboard
2) One isolation switch on 240v, then beefy transformer (capable of running all LEDS) and then 12v circuit to each cupboard with two strips connected to door switch for each cupboard. Presumably this would leave the transformer powered up with no load if the isolation switch was on, but cupboards closed, this doesn't seem right to me.
3) Other?

Many thanks

 

[ban-all-sheds]

1) Yes. Wire each pair of door switches in parallel so that opening either door will cause both strips for that cupboard to come on.

2) No - always switch the LV side, not ELV. The supplies may not like running with no load.

3) Solid doors, or louvre? I've got the latter on a built-in wardrobe with 3 pairs of doors, wired as per my suggestion in (1), but also with an override switch for all 3 sets of lights so I can have them all on with the doors closed.

 

[jayjay]

Thanks for that! We are not using louvred doors, but nice tip if you are.

 

[bernardgreen]

2) No - always switch the LV side, not ELV. The supplies may not like running with no load

LV refers to mains voltage

Valid for switched mode supplies, not necessarily valid for wound transformers which can be left powered with no load. ( but still have a switch in the mains supply for maintainance etc etc ). This allows the switches on the doors to be wired as ELV avoiding the need for 230 volt insulation and protection of cabling and switches.

 

[ban-all-sheds]

LEDs.

No chance that the supply will be a simple wirewound transformer....

[EDIT] Apparently there is [/EDIT]

 

[RF Lighting]

I've quite sucessfully run LED strips off a 'proper' transformer as the SMPS I tried at first refused to dim.

I had to make a bridge rectifier to go on the output, but I keep diodes in stock anyway.

 

[Sherbertlion]

LEDs.

No chance that the supply will be a simple wirewound transformer....

Could be.

http://www.mr-resistor.co.uk/uploads/dimming_tape.pdf

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