Power over CAT5/6

I am planning to do a mod for an IKEA PS 2014 lamp, such as this: http://davidbliss.com/2014/11/18/transforming-sphere-lamp/ I see that the author uses CaT5 cable both for the motor assembly and for lighting. Hence my question: where can I find the specs for power over typical Cat5/6 cable? I understand that running 220V over it (as the original lamp requires) is a big no, but what is allowable? The lamp, cool as it looks, obscures quite a bit of light, so I would like to put as powerful LED bulb there as possible.

I have checked the power over Ethernet specs, but I cannot figure them out. Wiki e.g. says that one standard allows for 15.4W, while another (PoE+) allows for 25.5W. Should I understand it that this is what the cable itself allows for? Or are they using different cables? What am I missing here?

I think CAT6 is the 25W and CAT5 the 15W
The thicker wire is for high speed, not more current since CATX is data cable.

Whether or not you can run 250 V on CAT5 has more to do with the volatage rating of the insulation than the wire guage. CAT5 insulation is deliberately rated for low voltage. If it were rated for a higher valtage you probaly could use it for low current 250V circuits if it was rated for 300V. The CAT5 solid copper wire can probably carry 60 mA @ 250 V but the insulation is not rated for that voltage. That might be enough for a lot of things , but obviously not lighting.

Why not transform the 220V AC in the ceiling space and only send the DC voltages needed down the CAT5/6 to power the LED's and drive the stepper.

Another consideration for tungsten lamp fittings is that the insulation or wiring inside the
lamp fitting is high temperature rated. normal CAT5 is not high temperature rated. You can
get specialized ethernet cables, or avoid the issue with LED lighting (not that LED lighting needs
good heatsinking).

Jabberwock:
I understand that running 220V over it (as the original lamp requires) is a big no, but what is allowable? The lamp, cool as it looks, obscures quite a bit of light, so I would like to put as powerful LED bulb there as possible.

From the davidbliss site "I replaced the standard wiring with a Cat5 ethernet cable to connect my electronics in that cap to the motor and LEDs in the body of the lamp. Four of the Cat5 wires are used to control the motor and three for the LEDs, leaving one unused wire."

David is NOT running 220v through the Cat 5 cable, "the lamp is powered by two 5V supplies. The first is a 2 amp supply used for the Arduino and motor plugged into the Arduino’s barrel jack. The second supply is a 10 amp supply connected to the LEDs"