The guidance issued within the On-Site Guide (OSG) published by the IET is helpful in deciding on the nature of cable support and the distances recommended between clips.
Appendix D covers cables generally, specific applications such as caravans and the like, overhead wiring as well as conduit and trunking support.
Table D1 details spacings of supports for cables in accessible positions. Fig 2 gives an example of the recommended distance between clips for a cable having a diameter not exceeding 9 mm based on Table D1. As the cable diameter increases the distance between clips is permitted to grow.
Fig 2 Cable supports example - image courtesy of T.J. Bratley
Whilst the support distances are important, it remains the case that the purpose of cable supports is to ensure there is no undue strain on the cable or its terminations.
For more information, check out our SGTV episode on Cable Management Systems at https://youtu.be/9qdwKzCJm6Q