With such a small load, I would jump power from the house (unless you plan to do other things in the future, which will require more power). The NEC 225.6(A) requires a minimum of 10 awg for distances up to 50 feet. You will need weatherproof wire. I would use a wire size larger if you have winter weather. If hot weather, then leave some slack in your wire. You must make sure your wire will support itself, as well as the load, without excessive voltage drop.
I believe-from what I'm reading-that a #10 will work well for you. You will need a disconnecting means, which can be a snap switch, or breaker.
Just a few things. Wait for others to respond with more, or better information.
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