Yeah..

I was quite sure that this wont work, but we have been forced to try.. Not that much.. 😛
Normally the LAN is got over FTP and UTP cables, aka the twisted ones.. Yeah, the twisted wires.. Or even twisted pairs of twisted wires.. Cat6e has 6 twists per inch..
But using old 12 x 1.5mm² AC mains cable with no twists which is 20 to 30 meters long, is under ground and dated to late 70’s or 80’s must fail..or..?

why this could work?
1st: i used only 10Mb/s mode
2nd: we were totally lucky

update 2/2017: i will be finishing this project soon!