Will this setup cause a fire?

David82:
What other cable can carry that kind of power and data while being able to be bought locally in different lengths? Cat5 is very convenient. An extension chord would be good too but it only has 3 wires. I need power, RX, TX, and video signal all on one cable.

Part of most national safety codes is that one is not allowed to carry both AC power and DC signals within the same cable assembly, unless it's some specially build cable that is in effect two cables enclosed in one overall cable. This path you seem determined to keep on is with not a good one to pursue.

Lefty