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The people that lived in the house before me did something odd. They evidently intended on putting in under cabinet lighting in the kitchen, so when they tiled the back wall all around the area, they put in a wall switch that ends in two wires just capped off. (The lighting was never finished.)

The switch is right above the counter, and the hole where the wires come out are just above the tile, 1' or so above the switch. I have already confirmed that the wires and switch are live, so for now I have the wires still capped, and the low profile rocker switch taped in the 'off' position.

I would like to run LED lights for under cabinet lighting, and I've been looking at some of the linkable 6" and 12" strips.

How would you go about wiring a transformer to this? I've been looking at these power supplies, assuming I choose the correct size for the LED bars, is it as simple as wiring in the two wires leading from the switch?

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You're planning on mounting the transformer to the bottom of the cabinet, with the romex wire that comes out of the wall directly hardwired into the transformer? I'm not sure if you can hardwire it like that exactly, but you most definitely can't have the contacts on the transformer exposed like that- it would have to be in an enclosure. A picture of where the wire comes out now may help someone provide suggestions. – gregmac Jun 2 '14 at 21:42
@gregmac - I can take a picture of that when I get home. And from what I can see on the transformer, there is a cover that goes over the contact screws. But yes, that was the plan. d114hh0cykhyb0.cloudfront.net/images/uploads/… – JohnP Jun 2 '14 at 21:43
@gregmac - It's not Romex. I forgot to take pictures, but it's two wires only. It looks very similar to what it would look like if you took a standard electrical cord and wired it to the switch. I have not taken the switch out to see what comes into it as a source yet, either. – JohnP Jun 3 '14 at 16:43

Romex is not supposed to just stick out of the wall. Any in-wall wiring is only supposed to connect to out-of-wall wiring through a junction box. The cleanest way to do that is to put in an electrical outlet.

You can get retrofit junction boxes that just hold on to the drywall, which makes it quite easy to add an outlet.

retrofit box

Also, those power supplies may be way overkill. How much lighting are you planning to install? I just installed about 8 feet of strip LED lights and it's using about 2 watts. If the power supply is over-rated by 10 times, it's wasting power just sitting there turned on.

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It's not romex, see my comment to gregmac above. – JohnP Jun 3 '14 at 16:44
If it's just lamp-cord running inside the wall from the switch, that's even worse (there are in-wall fire-resistance requirements on the wire insulation which lamp-cord is not rated for typically). I would really replace that cord with romex from the switch to an outlet junction box. – Grunthos Jun 3 '14 at 16:51

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