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12V over ethernet ( CAT5) Answered

Hello, I need to transport 12V of molex output from a computer power supply over 10 meters to feed a touchscreen. My house has CAT5 cabling. Can i use that? Does someone have a step to step procdedure to make this cable ? Any ideas ? Thanx! Henri, Hilversum / The Netherlands



get a secondary PSU

Power over Ethernet has been around a long time - PoE. Because the cables are not rated for a lot of current, they trade off, and standard PoE equipment runs nominally at ~50 volts. IEEE Standards say you shouldn't put more than 15 watts in, and with cable losses get about 12.5 watts out the other end safely. (10-400mA) if using 2 non-data pairs in the cable. (Green and Orange pairs are data, Blue and Brown are power, normally unused)

http://en.wikipedia.org/wiki/Power_over_ethernet <<great read

I would recommend wiring 2 pairs + and 2 pairs - to be safest. Send higher VOLTAGE rather than AMPERAGE for safety, then convert it at the other end. Voltage degrades less over long cable runs. I would also recommend wiring directly to the molex connector, nix the RJ-45 jack, it's not meant for high power at all.

**and Zerogx has it exactly right - wrong voltage on the wrong pins going into your switch will kill the port or worse the switch. All the more reason to not use an RJ45 connector, no accidental plugins.

As CAT5 is not designed for power transmission, you may find that you've got significant losses over 10 M. What connectors do you need and have you got any - RJ45? L

The controller of the touchscreen has an male molex which i connect to a molex
at the rear of my pc.
is this the way to do it ?

touchscrren/molex to rj45-------------------------rj45---molex/computer



Answer 9 years ago

it might work, but the ethernet cable you are using CANNOT connect at ANY point to the switch. the one cable you would be using must connect only to the computer and to the touchscreen.

a much easier way would be to mod a computer power supply, an instructable is here and only use this psu for the touchscreen.

In theory, but read comment by ZEROGX. You might be better with a battery instead?



9 years ago

if the wiring goes to a central switch at one end, then probably not. they make devices called a power of ethernet injector, which feeds power into ethernet lines. some info can be found here : link you also might be able to splice a 12 volt power supply into the ethenet cable.