Oval conduit for 4mm² T&E

[echoes]

A very quick question: what size oval conduit would you recommend for ungrouped 4mm² T&E? (major axis = 10mm).

16mm conduit gives a space factor of about 50%.
22mm conduit gives a space factor of about 25%

I think I have just answered my own question....

 

[PrenticeBoyofDerry]

Because the cable is T&E, I'd work on the ease of pull, rather than the space factor.
Pulling 2.5mm T&E through 16mm oval conduit can be difficult enough, so if your wall levels allow you 22mm. I would go with that.

 

[echoes]

Thanks - but due to consideration of de-rating (another post), it'll be clipped direct!