The purpose of this paper is to investigate friction forces in the design of a single-core flexible cable in the deformation zone and the practical applicability of the results obtained for these purposes. The power interaction of the design of a single-core flexible cable during its deformation is considered. For the first time, formulas were obtained for determining the interaction forces between the constituent parts of a single-core cable as a composite multilayer beam. A calculation technique has been developed and shear force values have been determined for some types of single-core flexible cables. The nature of the change in these forces along the length of the cable is investigated. At the beginning of the cable deformation zone, the force value can fluctuate within its constant value. In the remaining part, the shear forces along the section are constant and only at the end of the deformation zone is zero. Practically, the formulas work for the tasks. The resulting expressions for shearing forces allow one to evaluate the tribological interaction of the constituent parts of each cable element and take into account their influence when creating multicore cables. The results of the research can be used to improve the reliability of the design of flexible cables at the design stage. Manuscript profile