Acceptable fusion splice loss: ≤0. 1 dB per joint (per ITU-T G. Final protection: strong, flexible, and strain-relieved. Do. At TREND Networks, we are frequently asked how much loss is allowed when conducting testing on fiber optic cabling. Unfortunately, it is not a simple answer and depends on several factors. So how do you determine acceptable loss? When testing fiber optic cabling, determining acceptable loss is. Reliable fiber optic networks demand strict control of splicing loss during fusion splicing. Network engineers recognize that both fiber quality and precise technique matter. 3 recommends a maximum value of 0. This value should be determined by the system designer. Fusion splicing is the most widely used method of splicing as it provides for the lowest loss and least reflectance, as well as providing the strongest and most reliable joint between two fibers.