I'm building a Wi-Fi controllable light switch that will use rocker style (up/down) plastic buttons. My plan is to have all the electronics enclosed behind a metal gang plate (the part that screws onto the gang box) in it's own plastic enclosure.
I would like to have plastic 'legs' on the back of the rocker switch (for up/down) that protrude into small holes in the single metal gang plate so that the plastic legs push tactile switches on the inside PCB, mounted behind the metal plate in the enclosed area. The depth of the holes is roughly 1.25 cm.
Some of the sensing electronics I'd like to keep mains referenced, so a non-isolated power supply would be preferable. I would like to have this UL certified eventually.
My question is simple. Do I need an isolated power supply in this case? The buttons will only ever be pressed by the plastic 'legs', not touched by a finger and everything else is enclosed.
Don't get me wrong, I have experience designing switching mode isolated power supplies in the past. But am not too sure of what I'll need in terms of certification for this specific case.
Any help / clarification / expertise is appreciated. Thanks.