OpenSCAD file can be used to very simply change sizes.
Print the clips on their sides.
cableguide.stl
is meant to be screwed to the underside of a table or desk and can hold up to 6 thick (power) cables.
cableguide-single.stl
can be used either on the underside of a desk or on a vertical plane. This one holds up to 3 thick power cables.
Other variations can easily be created using the parameters at the top of the OpenSCAD file.
The author hasn't provided the model origin yet.