Could I use old telephone wire to run 24VDC for LED lighting use?

[BrewFixer]

Hello,
I am in the middle of installing some 24VDC LED Strip lights in my daughters bedroom and was struggling on how to hide the transformer as I did not want to mount a box on the wall to conceal it or run wires through the wall into her closet. After thinking about this I happen to find the old telephone wire in a box behind her bed. I did a trace on the wire and found it in my basement server room which makes ideal.

My thought was to mount the transformer on the wall in my basement and use 2 of the 4 conductors from the telephone wire that run to her room as the 24VDC supply source to a Shelly RGBW2 which I would conceal in the telephone wire box and run all the LED wiring right into the box. While this sounds simple enough and I am possibly overthinking this I was wondering if there may be a drawback to this? As far as I can tell, the wire gauge is the same as the LED just solid instead of stranded.

Thanks in advance

 

[Timbo]

Volt drop will be an issue.

 

[Moley]

Volt drop will be an issue.

Maybe double up on the cores? It's 24v dc so we don't need to worry about crosstalk.

How long is the run?

 

[BrewFixer]

I thought about that but the Mean Wells power supply has some adjustment on the voltage side albeit that I am not sure if it will be enough to get me to my 24VDC at about 30' from the Shelly RGBW2.... However thanks for the reply as I am leaving nothing to chance. Only want to do this once correctly.

 

[BrewFixer]

About 30-40 feet from proposed source.

Maybe double up on the cores? It's 24v dc so we don't need to worry about crosstalk.

How long is the run?

About 30-40 feet from source. When you say double up on the core are referring to use two conductors for positive and 2 for negative?

 

[James]

How many amps is the power supply?

 

[BrewFixer]

How many amps is the power supply?

Mean Well - RSP-500-24​

24VDC / 21AMPS / 504 WATTS
With a voltage tolerance of 20-26.4

 

[Moley]

What LEDs are you fitting? What Watts are what?

 

[pc1966]

24VDC / 21AMPS / 504 WATTS

Telephone cable will be luck to support much more then 1A so you run a serious fire risk if you are thinking of putting a 21A supply on it. It would need to be fused down.

You need to start with the total power of the LED lights, determine the required current, and then see if the wire might be usable.

 

[BrewFixer]

300 LED's per run @ 0.1A per LED Gives me a 3A load per run. I am planning a run of 3.5 strips.
Max Watts would be 120W per run.

 

[Timbo]

300 LED's per run @ 0.1A per LED Gives me a 3A load per run. I am planning a run of 3.5 strips.
Max Watts would be 120W per run.

420W/24v=17.5A
Could get the phone wires buzzing!

 

[Moley]

And there was me thinking just a few LEDs ?

 

[7029 dave]

The cable in question is for telephony only, it is not designed to take that amount of current.

 

[Mark42]

300 LED's per run @ 0.1A per LED Gives me a 3A load per run. I am planning a run of 3.5 strips.
Max Watts would be 120W per run.

If those figures are right (and I’m not convinced they are as that’s very bright) using phone cable would be absolutely fine.
For about 20 seconds.
After which time the cable would melt and catch fire, quite likely setting fire to your daughter’s bedroom.

 

[UKMeterman]

That is a 500W supply that MUST BE ENCLOSED it has exposed screw terminals. 500W is also very bright for LED!! It would be like inside a lighthouse, 25W LED would be more reasonable design load, but still overkill.