? using Cat5 for 12v led lighting

[scubado]

I need some opions on using Cat5 cable to run 12v led lights. My 12v controller will be in my basement to control led's out on my raised flower beds. Each channel will have 20 leds with a total of 32 channels with an exception of two channels having 40 led's on them. One length is 30', the other is about 120'. I will have 4 cat5 cables and one 14g wire(common) inside a 1/2 " conduit. Do you think this will be adequate? The led's are 20mA each.

[JBullard]

My concern would be 4 non-data cat5 cables inside a 1/2 inch conduit, regarding heat build up. The cat5 is a twisted cable, in a jacket then 4 of them in a small conduit would cause me to pause.

I've had no problems running 150 ma through a cat5 conductor, in free air.

I don't remember the cat5 specs off hand, maybe some one else has the specs handy and can better comment on the current handling and heat dispensation requirements you would need, in conduit.

[Dave Batzdorf]

I do know that the cat-5 will handle the current, but I don't I would do it for 4 circuits. Here is a reference concerning PoE - Power over Ether which is something that we do at work.

http://en.wikipedia.org/wiki/Power_over_Ethernet

Bottom line - I wouldn't. (imho)

[Max-Paul]

What I am going to say is based on past knowledge and a gut feeling about what you hope to do. First I am not sure if Cat 5 cable is 20 or 22ga wire. Although I believe it is 22 ga wire. I know that you are safe with 5 amps in 18 ga. So again this is an educated guess that 22 ga wire I would not push much over 1.25 amps. And if by chance this is 24ga wire. Then I think the circuit with 40 LEDs will be like .8 Amps and I think 24ga wire is only good for about .6 Amps. But I suggest that you do some googleing for yourself and learn some of this for yourself. We will still be here to help.

I agree with the others 4 cat 5 cables in 1/2" conduit is just to tight. Maybe 3/4" would be more like it. And the only other concern is that a 120' run might cause some voltage drop due to the resistance of the wire. When all is said and done. It is possible that you will only have say 9 volts max at the end of the 120' with your LED load. Again this is something I would test out before making the conduit run. BTW is this the circuit with the 40 LED?

[scubado]

Yes the two lines with forty leds is on the longer run. I took a closer look at the wire and it's 23awg. I found this wire chart with current ratings, but I don't understand the last three columns. Could someone shed some led light on it?

Attached files WireTable11.pdf

[Dan Ancona]

Sprinkler wire may be another good option for you to explore. Since you're planning on burying the conduit, the sprinkler wire is made for direct contact and is typically of a larger guage. You can find several different conector wire.

[Max-Paul]

I am not real happy about the table ratings that you found. Nor am I happy with the table for the link I am about to provide. But at the bottom of the page there is a calculator that if you plug in different values will give you an idea about the voltage drop I was talking about. The part about the length of cable run is a bit confusing. But just put in 120 feet and not the total back and forth length of 240 feet. It will do that automatically from your 120 feet info. Notice how changing the current info will change the amount of voltage drop.

http://www.powerstream.com/Wire_Size.htm

I am going to post a different link for a current to wire size that I know is closer to the situation that you will be using it for. Notice how the 10 gage wire is rated for 55 amps. I dont think that is correct for our case. Maybe 30 amps, but not 55 nor 15.

I found this chart:

AWG   Feet/Ohm  Ohms/100ft  Ampacity*
10    490.2       .204        30
12    308.7       .324        20
14    193.8       .516        15
16    122.3       .818        10
18     76.8       1.30         5
20     48.1       2.08        3.3
22     30.3       3.30        2.1
24     19.1       5.24        1.3
26     12.0       8.32        0.8
28     7.55       13.2        0.5

AT
http://www.epanorama.net/documents/wiring/wire_resistance.html

[scubado]

I like the spinkler wire idea. 20awg and a variety of # of conductors. I came across a deal for 20/8 for heating/ac control wire. I thank you all for your help.

I normally an avid scuba diver, but this year I'm cutting way back on it to focus on this new hobby. It's almost tempting to sell my equipment to reinvest in this hobby, but I know I'll want to get back into the water again. Here's an idea if there's any one who lives on a lake, preferably one that freezes in the winter. Try sinking some high powered led's just below the surface and make the ice dance. Unfortunately I don't live on a lake, but thought it would be a cool idea.