This is a case for a power connecter with switch we bought on EBay. Previously, the power was directly wired into the PSU, which made the whole thing a little less portable.

Now we can unplug the printer and even turn it on & off from the side.

The box has lugs either side of it to mount onto the 2020 extruded rails.

You can download the Open SCAD files and modify the setup variables to adjust the size for your particular power switch. Printed with 20% in-fill and 2 loops. YMMV