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I'm in the process of remodeling my kitchen. I plan to install RGBW led strips on the top of the upper cabinets, below upper cabinets and below ground cabinets. I have to close off any wall holes and paint the whole thing tomorrow and my RGBW wire still hasn't arrived (ordered online).

Now the thing is that the range hood will divide the upper cabinets and there is no way to run a wire from one side to the other without it being visible after I tile up that wall tomorrow. The only solution is to run the wire behind the tiles, but that has to be done now and I still don't have the 5 wire cable at hand, but I do have some spare LAN cable.

Do you think it will be okay if I put a LAN cable in the wall now behind the tiles and then connect the two LED strip parts with it instead of a RGBW 5-wire cable?

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Past few weeks I have really come to appreciate the benefits of cable pull string. A nylon string used to help pull cables. You can drill the holes in the walls, cover them up and then when you get your cable, tie and tape it on one end, then pull from the other. Just make sure you make the holes big enough to pass the flat ribbon RGBW cable through along with the knots.

If you don't have cable pull string, you can get it at most hardware stores and the big box stores. You can also just use any strong string or twine you have. If you have UTP cable you can put that in temporarily then use it as a pull cord but it's not as strong as the pull string. That shouldn't be a problem for a small run like you're describing if it doesn't have a lot of sharp bends.

The problem with running UTP is that it's normally 24 gauge and even though it might just be a temporary fix, temporary can sometimes be a very long time as long as everything appears to be working and you have other things to do. So it's thinner than the usually 22 gauge RGBW cable conductors. According to this table on wire properties 22 gauge wire can handle up to 0.92 amps for power transmission and 24 gauge wire only 0.577 amps. If you know how many amps your light setup will use then you can make a safe decision.

When you have to use a different wire it's better to go with a larger size than a smaller size. You can get 5 conductor thermostat wire most places and that's generally 18 gauge. 18 gauge wire can handle up to 2.9 amps for power transmission so it's the safer choice.

I would personally just make the holes, pass some string, leaving plenty on each end to tie and grab, then install the cable when you get it.

  • Just as a reference point, looking at the PoE specs give a good baseline - IEEE 802.3at specifies a 30 watt maximum continuous draw over Cat5 with a 600 mA maximum current draw. – Comintern Nov 7 '15 at 4:58
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Assuming only low-voltage goes through that wire:

You only need to worry about the voltage drop in these thin wires.

It depends on the length of the cable, voltage, and the total Ampers that go through that cable. Since CAT5 cable is 24 AWG, you can calculate the voltage drop, for example using this calculator (substitute your own numbers):

Say, your RGB LEDs run on 12V, and each color runs 24W max, and the cable length is 20feet:

each strand will have 24W/12V=2A max, and the voltage drop will be, according to that calculator, 2V. So your LEDs will get a bit dimmer (get only 10V out of 12V), but probably will still be bright enough.

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    Remember that there is also current flow in the return conductor. Thus there is also an equivalent voltage drop in that return wire so, using your example, the LED load will see only 8V out of the 12V. – Michael Karas Nov 7 '15 at 13:00
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what is the voltage of the strips you are using, low voltage ones like the 24v ones may work but remember the wire is listed as communications cable not power. if they are the 120v style no (the insulation wont hold up over time).

  • I will be using 24V strips. – gvmk Nov 7 '15 at 16:38
  • cat 5e cable I have is 24 gauge if you tie two pairs together it will provide more ampacity you should be able to pull 1 amp at 24v without a problem – Ed Beal Nov 9 '15 at 14:04

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