The back of the HS200 says "Output: 15A Maximum Load General Use, 5A Incandescent" Why would the incandescent load (a purely resistive load) be less that the maximum load? [Typically inductive loads a

I want to wire the HS200 to the bottom receptacle of an outlet. I am running 12/3 to the outlet. Is this possible? My goal is to have an always hot receptacle and run 2 more outlets off this first out