In the automotive industry, arranging wire harnesses in assembly plants requires manual work. The stiffness of the high-voltage cable implies that personnel applies sufficient force on the cable to achieve a proper installation. Sometimes, the applied force is not strong enough; thus, the cable is not properly installed, or the personnel gets injured, raising ergonomic concerns that need attention. The challenges arise from the intrinsic cable characteristics such as diameter, copper type, cable strand quantity, first-layer insulator, cable insulator glue, and protective covering. The primary objective of this research is to examine how various factors, such as cable length and protective covering, impact the mechanical properties that influence the assembly of high-voltage cables. The methodology proposed consisted of characterizing the mechanical properties of the high-voltage cables in a cantilever beam test to measure deflection in response to an applied force. The measured properties were contrasted through a Finite Element Analysis of the high-voltage cable. The results validated the initial hypothesis, revealing two key findings. Firstly, the stiffness of cables varies with increasing length. Secondly, cables with tape exhibit greater stiffness than those with conduit and cables without covering, as detailed in the results section. In conclusion, extending cables without attachment points is recommended until the interfaces and environment permit. Furthermore, minimizing tape for cable protection while exploring alternative safeguards can enhance stiffness and facilitate an ergonomic installation assembly under favorable conditions. This study contributes valuable insights for optimizing high-voltage cable installation processes in assembly plants, addressing stiffness concerns through informed choices and design considerations.