UPDATE 6/2/2018 !!! - Added another version where the Phoenix connector is held down by a zip tie. See the 'v2' version of the file.
ORIGINAL - My FolgerTech FT-i3 Mega came with these 4 pin Phoenix connectors (male and female mated together) to split the wiring for dual Z axis motors. I didn't like that the phoenix connectors were free hanging, so I made a mount for it. the hole is sized for an M5 cap head bolt. ~ 8 - 10mm. the mount is 30mm wide. The mount includes tabs at all four corners for strain relief (not that it should really need it, but I like to tie things down when possible). Small zip ties should fit in the holes in the corner tabs to tie the wires down.
The fit is pretty tight. Lay the mount flat on a table, then push the phoenix connectors down between the two posts. the posts should bend enough for the phoenix connector to slip down. Just be careful and the posts shouldn't break.