What is the distance you can run 10-2 wire?

Depends on what it is powering. The longer the run the more voltage drop you get. For example if you run 200 feet of copper 10 wire you'll lose about 4 volts. There are voltage calculators you can use. The less volts you have the more amps the wire will have. Watts/volts=amps. 10 wire is rated for 30 amps. Do the calculation. You should not go past 80% of 30 amps (24 amps).