The normal recommendation for fiber optic cable is the minimum bend radius under tension during pulling is 20 times the diameter of the cable (d). When not under tension (after installation), the minimum recommended long term bend radius is 10 times the cable diameter.
Bend Radius is the minimum allowable cable bending beyond which refraction of light may occur and escape through cladding hence increase attenuation and degrade bandwidth performance.
Important factors that mainly affects allowable bend radius:
•Type of fiber cable
•Outside Diameter(OD)
•Condition of cable under stress caused during installation(tensile load)
•Condition of cable under no stress after installation(no-load)
N.B: Extra loss caused by the bending of optical fiber with bending radius much larger than its overall diameter is technically referred to as macrobending loss.
