USB Relay Box

I printed it with 3 walls with 15% infill. 

You need 4x 10mm M3 bolts for receptacles, 2x 30mm M3 bolts for cover, and 6x M3 nylock nuts.

My relay module has, a USB-B connector and it is labeled as HW-348. I made some tolerance for the PCB because they are not consistent with dimensions.

I bought some generic IEC receptacles, hopefully they are standard.

I encourage You to put some 10A (or even 6A) fuse inside as your electric circuit is probably rated to 16A (most of Europe I think?), but relay and receptacles are rated to 10A.