An IoT-Based Power Phase Failure Detection and Notification System is an advanced solution that monitors the health of three-phase electrical supply systems in real-time. Using voltage sensors connected to an IoT microcontroller like an ESP32 or Arduino, the system continuously measures and analyzes each phase (R, Y, B). If a phase failure, imbalance, undervoltage, or overvoltage is detected, the system immediately triggers an alert. This allows for rapid identification of electrical faults, helping to prevent equipment damage, operational downtime, and safety hazards in industrial, commercial, and agricultural settings.