I would like to link our house and garage using cat5/6 data cable
allowing internet to be shared. The route i would like to take
requires digging a trench and the total cable distance comes to about
70m inluding going around walls etc.
External grade armoured cable seems to be obscenely expensive so would
some kind of outdoor grade cable within a conduit be acceptable?

also the garage and house are on completely different electricity
mains supplies with different meters etc. Is this a problem in terms
of linking them because they have seperate grounds?

thank you for your help
Pete