An arc flash is a sudden, high-energy electrical discharge that releases intense heat, light, pressure waves and molten debris within milliseconds, posing a serious risk of fire, equipment damage and injury near AC panels, switchgear and distribution boards. Conventional protection devices such as MCBs and fuses are designed for overcurrent and short-circuit conditions and often respond too slowly, or not at all, to the fast, low-energy signatures that precede a full arc fault. This paper proposes a low-cost, IoT-enabled embedded system built around an ESP32 controller that continuously monitors multiple physical signatures of an incipient arc — light, current, voltage, temperature and, optionally, sound

— correlates them using a threshold-based detection algorithm, and rapidly disconnects the AC supply before the fault escalates, while logging and reporting the event to a remote dashboard. A working hardware prototype, built around an Arduino Nano controller with current, voltage and optical arc-flash sensing, local LCD/LED/buzzer indication, and a relay-driven output breaker, validates the core sensing and trip logic of the design. The system is intended as a retrofittable, multi-sensor alternative to single-parameter, current-only arc-fault protection for residential, commercial and small industrial installations.

Keywords— Arc flash detection; arc fault protection; ESP32; IoT; multi-sensor fusion; ACS712; ZMPT101B