Conduit Factors

[Student1993]

Afternoon, I am a student studying electrical Instalations, I have an exam coming up in a few days and I'm really struggling understanding conduit factors, I have an onsite guide but the thing that is confusing to me is the numbers of the factors for example: conduit diameter is 16mm and the factor is 290.. what does the 290 stand for?! 

I would appreciate any help, thank you. 

 

[Zeespark]

Each size of cable has a conduit Factor, specific to itself, the factors can be found in the OSG.

Andy  Guinness

 

[Andy™]

the conduit has a factor number (i.e your 290 for a 16mm dia). each cable then has a factor (i.e stranded 2.5 is 43). add up your cable factors and make sure they are lower than the conduit factor

so if you use a 20mm conduit (short straight run) with a factor of 460, how many 2.5 stranded with a factor of 43 will fit inside?