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I am wiring in some 5050 RGB LED strip lights in my basement. There is a small utility room adjoining and I'm keen to keep the transformers and signal amplifiers in there in order that they can be hidden away, but remain accessible should anything need replacing in future.

I'm putting the lights behind coving like this: https://starscape.co.uk/project11.html

The only point in can bring the wires in to connect the LED strips is shown on the plan below. (This is because there is an RSJ blocking access before this point.) This means that I need to run some fairly long lengths of cable to connect the signal amps to the LED strips. This is shown on the plan below, and the simplified version below that:

enter image description here

There's a clearer version here which shows the lengths etc better.

The power supplies I am using are these (100W version), and the signal amps are these. I was going to use this RGB wire to connect the signal amps to the LED strips but was concerned about voltage drop / heat over the 3m / 8m lengths.

Is this cable OK to use, or should I use something heavier gauge? (If so, where can I get this (in the UK)? Considered 3 core and earth, but don't like the idea of using it for DC as it seems "wrong" / confusing to send current on the earth / use non-standard colours etc.

As far as I can work out the cable is about 20AWG. I've been getting royally confused trying to work out the voltage drop and:

a) whether this is relevant (some sites seem to suggest the LED drivers compensate for this)

b) what gauge wire I need (according to my sums I need 14AWG to keep the VD to a minimum, but the fact that no-one readily sells this for LED lights makes me think I'm misunderstanding something

If anyone has any real world experience of this I'd love some advice!

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Is 5050 the model number or the quantity of leds?

The cable you linked to looks very lightweight - you don't need a lot of copper to run leds directly off of low voltage DC but you do need to handle it a lot during installation.

I would get something heavier, just for the mechanical advantage. 16AWG stranded 300 volt should do nicely, the voltage rating is to get thicker insulation. You can get spools of it in many colours from any electronics supplier (not electrical, "electronics") in the local phone book. Also pick up an automatic wire stripper and a decent crimping tool while you are there - the common stamped-steel crimpers do NOT do a good job, and you don't want to have to get in behind the walls twice.

  • Thanks for this. 5050 is the chip type, and there are 60 LEDs per meter. Will go and hunt for cable! – Ben Nov 17 '14 at 10:02
  • This looks promising - can you take a look at the spec and see if it's viable? (It's 1.5mm, 500V rated, so higher than you specced.) uk.rs-online.com/web/p/multicore-industrial-cable/0141249 – Ben Nov 17 '14 at 10:30
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It's easier than all that. LED strips can be daisy-chained (within reason) and can be fed at any points, plural. I'm assuming you want all 15m of strip to be controlled the same way, you're not trying to split the segments for independent control.

The strips already have power buses going down them, and you can use those to daisy-chain, but they have limits of about 7-10 meters. You can beat those limits by running parallel "feeder" wire and tie to the strip as convenient. Most 5050/300 strips are rated for 0.4 amps per meter per color (1.2A on the common).

By "daisy-chaining" I mean connect each wire of the second strip to the end of the first strip as discussed here. That's 4 wires for RGB strips. And you can use premade connectors or solder the wires as works for you. However you can only daisy-chain so far, with an absolute limit of typically 10 meters (i.e. two 5m strips back to back) but even that will result in notable brightness difference between the two ends (unless you use feeder).

The hard part is the physical installation, so I would make that the primary focus, not keeping the strips at a particular length. I would cut and splice the LED strips as the physical installation demands. Be thinking about where you're going to feed power.

One option here is to create an actual loop. That would involve running 4 wires to connect the ends of your blue and red strips. If you are feeding a 3-strip loop (15m) then by definition every point on the loop is within 1-1/2 strips of every other point. You could feed it in one location! But I wouldn't, because if the loop breaks, one spot would have to handle 3 strips worth of power.

Feeder doesn't have to go all the way around the room, it could be partial. For instance I might continue the "loop" wire as a feeder wire along the bottom wall (right by the utility room) and attach the power/controller in one place: to the feeder.

5050 strips at 60 lamps/meter are usually 0.4 amps per meter per color (rated) but in practice a bit less than that, as their resistors are set for 13.8 volt automobile alternator voltage, not true 12V. You don't need 300V wire (but you'll have trouble finding a lower voltage). I do not recommend 600V as it's wild overkill, and in my experience, rather difficult to obtain in 18ga (1.0mm).

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