In modern power systems, continuous and reliable electricity supply is crucial, especially for sensitive single-phase loads. In areas using a three-phase distribution network, failure of one or more phases often leads to power interruptions and equipment damage. This paper presents the design and implementation of an IoT-based automatic phase selection system for three-phase power lines. The proposed system automatically detects phase failure and switches to an available healthy phase to ensure continuous supply. Furthermore, using Internet of Things (IoT) technology, real-time monitoring and fault notifications are provided through a web or mobile dashboard. The system is built using an ESP32 microcontroller, voltage sensing circuits, relays, and a Wi-Fi-based IoT platform (such as Blynk or Thing Speak).