▁radius ▁to ▁which ▁the ▁cable ▁may ▁safely ▁be ▁bent ▁during ▁installation , ▁and ▁for ▁the ▁long ▁term . ▁The ▁former ▁is ▁somewhat ▁larger ▁than ▁the ▁latter . ▁The ▁minimum ▁b end ▁radius ▁is ▁in ▁general ▁also ▁a ▁function ▁of ▁tens ile ▁str esses , ▁e . g ., ▁during ▁installation , ▁while ▁being ▁bent ▁around ▁a ▁she ave ▁while ▁the ▁fi ber ▁or ▁cable ▁is ▁under ▁t ension . ▁If ▁no ▁minimum ▁b end ▁radius ▁is ▁specified , ▁one ▁is ▁usually ▁safe ▁in ▁assuming ▁a ▁minimum ▁long - term ▁low - str ess ▁radius ▁not ▁less ▁than ▁ 1 5 ▁times ▁the ▁cable ▁diameter , ▁or ▁ 2 ▁inches . ▁ ▁Bes ide ▁mechanical ▁destruction , ▁another ▁reason ▁why ▁one ▁should ▁avoid ▁excess ive ▁b ending ▁of ▁fi ber - opt ic ▁c ables ▁is ▁to ▁minim ize ▁micro b ending ▁and ▁macro b ending ▁losses . ▁Micro b ending ▁causes ▁light ▁at ten u ation ▁induced ▁by ▁de formation ▁of ▁the ▁fi ber ▁while ▁macro b ending ▁causes ▁the ▁leak age ▁of ▁light ▁through ▁the ▁fi ber ▁cl adding ▁and ▁this ▁is ▁more ▁likely ▁to ▁happen ▁where ▁the ▁fi ber ▁is ▁excess ively ▁bent . ▁ ▁Other ▁applications ▁St rain ▁gau ges ▁also ▁have ▁a ▁minimum ▁b ending ▁radius . ▁This ▁radius ▁is ▁the ▁radius ▁below ▁which ▁the ▁stra in ▁gauge ▁will ▁mal function . ▁ ▁For ▁metal ▁tub ing , ▁b end ▁radius ▁is ▁to ▁the ▁center line ▁of ▁tub ing , ▁not ▁the ▁exterior . ▁ ▁References ▁ ▁External ▁links