The minimal bend radius of wiring conduits KOPOS is expressed in millimetres and relates to the inner central axis of the tube (see the figure).

Nominal dimension Minimal bend radius (mm)
EN ČSN
16   60
  13,5 70
20   80
  16 80
25   100
  23 100
32   120
  29 140
40   170
  36 200
50   220
  48 250
63   250