# Calculation of the resistance of the sheath

 I would like to calculate Rs (resistance of the sheath - IEC 60287 - 2.3.1) in order to calculate the loss factor sheath and screen. My question is : how to calculate Rs20 (conductor resistance at 20oC) ? I think I have to use something similar to : R20 = ρ*l/csa (ρ : resitivity,Ω.m ; l : length,m ; csa : current section area,m2 ), but what does I have to use instead of the CSA ? asked 10/10/2013 Paul Mercier2

 You formula is correct.  You could possibly get the CSA from the cable manufacturer.  If you know the cable construction and dimensions, you could calculate this. You could Google.  I've just tried this myself and I'm a little surprised at how little information there is.  Also if you look on the site, under Tools -> Steven's Technical List -> Cables, you can find some typical CSA (check the ABB guide first). answered 10/15/2013 Steven McFadyen 246

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