I am working on a wiring project at my home, and I have a specific question about whether something I am doing is advisable or allowed by the NEC.
I have a branch circuit with a 20 A breaker and 12 gauge wire throughout. It feeds a 20 A GFCI duplex outlet in the garage. Downstream from the GFCI is a 15 A duplex outlet outside near the eaves of the house, serving as a connection point for Christmas lights. Both receptacles in this 15 A duplex outlet are controlled by a 15 A smart switch inside the home.
I am concerned about both receptacles in the 15 A duplex outlet being controlled by a 15 A switch while on 20 A branch circuit. I know not to overload the switched receptacles beyond 15 A, but I have no guarantee that anyone in the future will know that. What if someone loads up one receptacle to 12 A and then the other to 5 A? Then the switch would have 17 A through it, exceeding its rating, without tripping the breaker. Perhaps I am misunderstanding; is the maximum rated current for a 15 A duplex outlet 15 A total, or 15 A per receptacle? If it's per receptacle, then I am in trouble. I think a solution, if this is the case, would be to have only one of the receptacles in the 15 A duplex outlet controlled by the switch.
Is it acceptable to use a 15 A switch to control both receptacles in a 15 A duplex outlet on a branch circuit with a 20 A breaker?