It's nice when a job is done! Because you've run a piece of #12 romex, you can put the wire on a 20 amp breaker if you choose. By being on a 15 amp breaker their isn't any harm.

I went overboard on my installation of power for my system. Even though it hasn't any effect on the power coming into the house I ran 8 dedicated circuits with metal clad cable. This is to supress any transient noises generated in the house from getting on the lines.

I posted elsewhere in the group about a whole house surge supressor at Home Depot for 40 dollars