I'm running speaker wires from our office to our kitchen and to our bathroom. How do I need to treat these as far as NEC goes? Do I need a certain type of box, etc?
I did get wire that was rated for in wall use. Beyond that, I don't know what's required.
You can run them almost anywhere except in the electrical box. They can pick up noise if you run them along other a/c supply lines - it's best to keep them away and cross at right angles, if required. Don't run them in an air duct. Other than that, I don't think there's an issue. One of the pros will beat on me if I've mislead you.