Can cat-5 carry ELK output for relay?

[dpilati]

I need to run some wires outside to control 3 outdoor items. I have some cat-5 lying around and I am going to use my ELK M1 Gold with an output expander module. At the other end is a 120V relay (Elk) and then a jumper on an HVAC. 
 
The distance isn't huge - like 30 feet. Am I fine to use cat-5?

 

[RAL]

If you are going to bury the cable, regular cat5 is definitely not suitable.   And even if you are going to run the cable in conduit, I wouldn't use it as conduit often leaks, if not initially, over time. There is direct burial cat5 cable if you really want to use cat5.  But it sounds like direct burial phone cable is really all you need in this application and will be less expensive. 

 

[Del91574]

How about what is the current and voltage that is going to be driven by the Elk...that would be more important than the type of wire as a first consideration.
 
Conduit generally doesn't leak if installed properly, the water inside comes from condensation. A wet location rated cable is what is called for in code.

 

[ano]

30 feet of Cat-5 cable will have almost 2 ohms of resistance per conductor.  If you are powering something, then double that because you are using two conductors, so maybe 4 ohms worse case. If current is very small you are probably OK, buy I wouldn't run more than maybe 100ma through it, and this would cause a voltage drop of about 0.4V, which should be O.K.
 
You also mentioned a 120V relay. Obviously you can't run 120V over this cable. 48V DC and below should be O.K.

 

[dpilati]

The relay takes 35 ma so it sounds that should be ok. But the burial and water issues are good points. I suppose irrigation cable would be fine but expensive - I just might have some around and it is locally available. I am referring to the 8 conductor type that has a thick black insulation - clearly this is made for buried/non conduit relay function - so it should be code compliant. 
 
Thanks for the help. 
 
Of course, I am sure the relays aren't rated for damp locations...

 

[tmbrown97]

Outdoor rated Cat5 should be fine as well - if there are current issues, you can always double conductors.  For the relay enclosure, I know many DIYers use things like the Pelican Cases - drilled for the wire then sealed with silicone.  There's also this Orbit box that I like using sometimes outdoors - it has an outlet inside and a mounting board you can use if you want.
 
Regular Cat5 will get destroyed outdoors - the stuff I use has braided steel and foil shielding along with UV/weather resistant coatings.  I don't use gel-filled too often because I do a lot of vertical runs too and the gel will move with gravity and find its way inside your cabinets.