This item can help if you make your own RepRap.
I designed it for Prusa i3 BOX frame.

This holder designed for the socket+AC filter, that I got from old power supply. Socket is soldered to filter board, so I left this assembly.

It is installed in the bottom right corner (if looking from the back it will be bottom left)
Align front plane with the bottom wooden plate.
Fix with several self-tapping screws.
I have used two 3.8x55mm screws vertically (item height is 45mm) and one 3.8x60 screw horizontally (item width is 50mm).

For output solder good wires for L, N and PE.