Cable sizing is one matter, but there are also requirements in terms of cable carrying capacities (and more) for conduit, including flexible conduit, as Adaptaflex explains:
UK Wiring Regulations (BS7671:2008 - 17th Edition) recommend that the total cross sectional area (CSA) of the sum of individual cables should not exceed 40% of the CSA of the conduit based on using three or more cables. The tables below enable users to calculate the number of conductors that can be run within a flexible conduit.
To read the full article, please click
on the link below to download it (Word doc - 27.5kB file size) and the associated
chemical resistance table (Word doc - 1.79MB file size).