Hello,
I’m thinking is this possible, maybe someone tried and maybe someone know? About 25m long.
Maybe is possible with power adapter with more amps?

Buy Omnitik UPA or HexPoe / HexPoe Lite / PowerBox/ PowerBox Lite
I know for that.
I I’m asking is this possible?
You can spare a wire using this:
http://forum.mikrotik.com/t/omnitik-upa-observations-issues/55443/66