What kind of wire/guage do I need to bury it if the circuit breaker coming from it is 240 volts 60amps?

(Chuckle Chuckle) Some of these answers. You need a 6/3 Copper Type UF cable, you wont have to worry about voltage drop till 250FT, Anything after that you'd have to go to a Larger size wire, you DO NOT have to put it in PVC Conduit, the wire is expensive enough, you will however have to bury it 2 feet (24 Inches) Deep as Per NEC(national Electrical code)

P.S. If you are running this to an Shed or detached Garage a 3 wire cable will NOT work, you'd need a 6/4 Copper you will also need to drive a Ground Rod At the Sub Fed Panel

Depending on how long of a run, #6 copper is good for about 75 to 100 feet. If you are direct burying the wire, use cable marked UF (for Underground Feeder), only . Not NM wire. Otherwise put the wire in conduit. Going farther than 75 to 100 feet, increase to the next wire size (#4) . If you are only running a 240 volt load, you only need two conductors, plus ground. If you are splitting the circuit into 120 volt

loads, you need to run 3three conductors, plus ground. Your ground conductor can be one wire size smaller than the current carrying conductors.

6/3 in conduit. # 10 is only rated for 30 amps.

If you want to bury wire, protect it with SS conduit. Forget that, 240v is NOT a DIY project. Get an electrician.

underground 6/3, I would say. Sounds like you are powering a outbuilding or something like that. Or 6 THHN in sched. 80 pvc.

My vote is 10 Guage. Sounds like you are running it for a clothes

dryer. It needs to be as heavy as your dryer cord.

8 gauge insulated wire ,and it must be in schedule 80 pvc conduit or similar watertight conduit.

brian d has the correct answer, but it should be mentioned in copper