This case study outlines a project undertaken by Fiber Optic Sensing Solutions Pvt Ltd (FOSS) to implement an Intrusion Detection Solution at an electric substation. The project objectives included providing 24×7 intrusion alerts, integrating the solution with the existing VMS, and maintaining a minimum nuisance and false alarm rate. FOSS carried out a thorough site survey and designed a two-layer fiber optic perimeter intrusion detection system (FO-PIDS) to detect any attempts to break the wall and gain entry to the premises. This case study showcases FOSS’s expertise in manufacturing fiber optic cable-based interrogators for distributed sensing applications and highlights the benefits of using fiber optic cable as a sensing element.