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I want to install LED strip lighting behind crown molding in my office. In my particular install, I'm using 3 strips of SMD 5050 RGBW LEDs, which draw about 72 W per strip. From what I can gather, people are using one of three kinds of power supplies:

  1. plug-in type wall warts
  2. panel-mount LED drivers like the Meanwell LPV series.
  3. Enclosed power supplies like the Meanwell NES series.

I don't believe there exists a magnetic transformer that can drive and control RGB or RGBW LEDs, but perhaps I'm missing a fourth option?

If I hire a professional to do this work (I'm not; I'm doing it myself, but I want a "professional" job that will pass inspection), what method would they use to drive my LEDs? The first two require multiple drivers since none are rated more than 100W or so. The latter method uses a power supply that's meant to be enclosed in a larger assembly; it's not meant to just hang out on top of a cabinet with exposed 120V input terminals.

So what are professionals doing when they install these systems? Do they install multiple 120V outlets spaced out behind the crown (or other feature they're accenting), and use multiple plug-in type drivers? Do they use an enclosed power supply which they then place within an enclosure of some sort? Do they fudge it, and just tuck the enclosed driver somewhere out of sight or where they think someone won't be likely to touch a live terminal?

I'm obviously not the first person to install LED accent lighting, but there's a dearth of info on the web as to how to install it, and actually respect Code at the same time.

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    I'm going to make a wild stab and say that you're probably finding a dearth of info regarding installing LED strips to code because doing a permanent installation of el-cheepo LED strips can't ever be 'to code'. Professionals who install fancy LED accent lighting probably use stuff like this (yes I work for that company, but not in that division) because it is UL listed and can be installed to code. – brhans Aug 30 '17 at 19:26
  • You mention 5050s. Some 5050s are white, but usually they are RGB color. if you are working with color LEDs, or if you want to dim them, that adds a complication that we need to know about. Dimming and color are the same issue, since color changing is simply dimming R,G and B separately. – Harper - Reinstate Monica Aug 30 '17 at 19:38
  • @brhans Code compliance relates to whether that product has seen the inside of a UL testing lab, it has nothing to do with the inherent style. So if he is satisfied with how the Cheese cheapies look, he can immediately swap them for identical products with the UL, CSA or TUV seal (at 4x the price). – Harper - Reinstate Monica Aug 30 '17 at 19:46
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    @Harper - yes I know - what I'm getting it is: is there such a thing as a LED strip of the type the OP describes which is UL (or whoever) listed&labeled for permanent installation in the manner described? If they don't exist as a UL/etc listed/labeled product, then there is might be no way to install such a thing 'to code'. Installing a fully enclosed all-in-one listed&labeled device to code is easy. Trying to install a bunch of separate bits & pieces which may or may not be individually listed&labeled is less easy and presents an increased professional risk to the installer. – brhans Aug 30 '17 at 19:59
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    Al LEDs are internally constant-current devices, and when you use a single large emitter, it must use a very special power supply which operates in constant-current mode and is correctly matched to that emitter. That is a "driver". These are small LEDs which are able to use a plain resistor for that, built into the strip. They are driven by a 12 or 24 volt constant-voltage supply. That's just a "power supply" :) – Harper - Reinstate Monica Aug 30 '17 at 20:24
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Just buy some 120volt LED rope lighting and forget about it. It comes with a driver already attached and can be cut to length every 18" or so.

They sell all different lengths and colors now.

Good,luck!

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    I appreciate the suggestion, but it doesn't address my original question. – the_meter413 Aug 31 '17 at 23:12
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I took a standard ATX power supply from a computer and took the 12V output to drive lights. I put it in a closet and ran romex through the way -- seems a bit strange to use such heavy wire, but it's (relatively) cheap, conforms to code for being in walls (most places), and reduces voltage drop. I put the power supply (in a small computer box) on a switched outlet so the 110V is switched, which reduces zombie current draw when the accent lights are not in use. IN my case I just fed a 110v run from the lights in a related area so the accent and regular lights go on and off together. (The manufacturer's remote can also turn off, leaving the power supply on).

I do not suggest this is code compliant, merely one approach that functions. Also, I feel a lot safer with a quality PC power supply than some of the cheap bricks, and much safer with romex in the out-of-sight runs than most cheap-LED-associated wiring.

Be sure to check the power supply to see its 12V structure, some carry full capacity on one bus, some have more than one to split the load, and you need to (for those) take care which outputs you use.

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As a professional installer of LEDs, I rarely use DC drivers. Most are 24v AC transformers located in an accessible closet or basement ran with #16 awg speaker wire. I prefer AC over DC simply because of the compatibility with ordinary dimmers which comes in handy when aesthetics is important. CRI is also important to some, but when cost is important, a lower CRI quality LED is just fine. I've used the ladder with 12v AC transformers for closets and even kitchens for a 3rd of the cost of the 24v systems with great results too.

  • Can you post an example/examples of the products you use? – the_meter413 Jul 30 '18 at 17:17

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