Single Circuit Transfer Switch

I recently designed a battery backup system for a well pump, and saved a tremendous amount of money in the process (video below). But without some sort of transfer / changeover switch, getting the well pump on battery power was obviously a fairly involved process. So I looked to solve that problem, and immediately realized that transfer switches are insanely priced! So, I wasted no time in firing up OnShape and throwing something together. This is what I came up with!

It uses a simple changeover switch and a power inlet (links at bottom). The faceplate could still use a little work to perfectly mold to the cutout of the switch, but it's functional as is. You'll need to drill holes if you want to mount the inlet and switch with screws, in which case I recommend 100% infill on the faceplate.

Oh, and the faceplate mounts to the case using 16mm (or shorter) M3 bolts. They should tap themselves in tightly if the dimensions are correct. They do hold quite well but they won't last for