I'm building an interactive portrait gallery with seventy portraits, each back-illuminated by an LED lamp. The lamps draw less than 30 mA at 230 Vac, and each is switched using a small optocoupler/phototriac, under microcontroller, er, control.
Given the very low current draw of the lamps, standard 3-core mains cable seems to be considerable overkill. (All of the wiring will be hidden within the gallery structure, out of the way of prying fingers; we have a mains bus, from which I can tap the connections for each lamp.)
Would a three-strand section of ribbon cable be up to the job? Some specs I've unearthed are rated to 300 Vrms (and up to 1 A), which would seem to be suitable. But what consideration would I have to give to voltage spikes?
I want to build something safe, but a lighter cable would make construction much simpler.
Best Answer
Mains cabling doesn't just have to supply power to your lamps; it also has to be safe in the event of a fault. If your lamp short circuits, you don't want the cable to burn out or start a fire before the fuse blows (if you're in a fused plug country like the UK) or the breaker trips! So standard 3-core mains cable probably is appropriate. See also MandoMando's comment on the correct insulation. Or as Dave Tweed says, use low voltage lighting and a mains transformer (perhaps look for garden or outdoor lighting systems)
EDIT: if the rest of the installation is up to "double insulation" standards with no exposed metalwork, then 2-core mains cable would be acceptable, saving some space.