Effective fault diagnosis is essential for reliable industrial processes. This paper presents a comprehensive real-time open switch fault detection approach for a single-phase double gain switched capacitor five-level inverter to enhance the system reliability, which has addressed a critical challenge in the operation of switch capacitor multilevel inverters. This approach can detect the faulty status, and simultaneously classify and locate eleven types of single-, double-, and multi-open switch faults. The average and absolute average values of the load voltage, and the voltage across the capacitor are analyzed for fault detection. The fault detection algorithm is derived through mathematical formulation and validated by extensive simulation and experiments under various operating conditions