Just wondering what are some characteristics of Cat5 cable are? Specifically I want to know how much current it can handle. I have used a pair to light 10 watts CFL bulb from 12 VDC using a inverter. Looks like it can easily handle 1 Amp.
Cat 5 is generally 24 AWG (US Spec) and in stranded or solid conductor should be able to handle 3 to 3.5 amps in chassis type open wiring. That would be my guess anyway.
Generally transferring "low" power through thinner wire doesn't bring up heating issues as much as voltage loss. 24AWG has a DC resistance of about 25 ohms per thousand feet.
A 10-foot long pair of 24AWG with a 12V input and a "10W" (833mA) load will deliver about 11.6 volts.
Of course you can improve this significantly by putting using all 4 pairs.
That's nice to know. I have few spare lengths of CAT5 cable I can use for DC cabling. Since the power source is 12V automotive battery, using CAT5 cable would diminish the voltage of 13.8 V (at full charge) to safe 12 V range. I plan to use mostly CFL and LED lights.
mneary's suggestion of combining pairs is a good idea as well.