In our Makerspace we have some Wallplugs and Wallswitches mounted for lights etc. Therefor we used the Roth Lange IP55 Switches and Plugs from Hornbach. Unlikely there is no space left inside the cases. So we made a case which fits under the case by using the space for the rubber cable feedthrough.
The Shelly case can be printed without supports (place the case on the hole side). Don't use supports for the screw head as it also can be printed without supports. When mounting, the case must be pushed with a little bit of force into the Roth Lange case.
Print with PETG or ABS. PETG V0 should be better here as it is better suited for electronics applications.
Upload files are without logos!
Also uploaded the OpenSCAD Script if someone needs to make some adjustments.
The author marked this model as their own original creation.