Reupload / improved version of a file from my thingiverse. It will go 1.0 when it does clips for twin and earth too.

Inspired or reminded by gnu'sCable Clip (Parametric) http://www.thingiverse.com/thing:39901 I remembered having made this openSCAD file that will generate three types of pipe or cable clip with either sharp or smoothed edges. 

I never finished making it into a proper library though as all the code needed re factoring. Here it is though, you can make the nail down sort of cable clip a split screw down type and an holder for a zip tie.

Edits

v0.95 - Slight tidy up for use with the customizer

V0.98 - Update 2023 - Still doesn't work how I consider a library but does draw parts individually and uses internal SCAD customizer

v0.99 Now works as a library, just comment out customizer section

v0.999 nail clip now uses tie width parameter so wide cables can be accommodated

Instructions

Download the SCAD file and tweak the parameters to suit in customizer window, they are all explained in the file.

Heres  a good video introducing openSCAD https://www.youtube.com/watch?v=cBesMfP7Ddo

If you are printing these for electrical cables be careful, they may not be considered up to code, in the least case use a material that has a high temperature of deflection and is preferably fire retardant. There are materials now one the market that would be suited to this such as BASF PC/ABS FR