Our son loves unplugging electrical cables, and there is an outlet right next to his crib where the baby monitor is plugged in. There are outlet box covers available at the hardware store that keep people and critters from messing with the plugs, but I had an idea for something simpler and more temporary.
This model prints as a single-line wall when sliced for a 0.4mm 3D printer nozzle. I went through a couple iterations before landing on this size and shape for my outlet covers. To use it, you just loosen the outlet cover screw a little, tuck it behind the plate, and slide it down. Easy as lyin’. Many of the photos here are from a prototype that I swapped out in about 15 seconds while the toddler was distracted during a diaper change. The slot fits around the front section of the outlet block itself behind the face plate, and it is think enough to deflect a little so everything fits easily.
I think this would be useful to have as an option to cover up outlets for a lot of reasons. It isn’t super durable, but it could protect against accidents pretty effectively. For example, we would have used it in a couple of hotel rooms either as a way to keep our son from unplugging his night light or as a little shelf to put the night light on.
The single-line walls make it a little flimsy. I tried slicing it in vase spiral contour mode in Cura, but it didn’t behave exactly I expected. The walls wound up being thicker above the point where it stopped being a closed loop. I wound up getting better results printing it with travel across the gap.
If you want to modify this design for your own outlet face plate sizes, or make an extra-big one for universal compatibility, you can start from my FreeCAD file.