The ABB PR121/P is a high‑performance electronic protection and trip unit designed for use with ABB SACE Emax low‑voltage air circuit breakers. It provides advanced overcurrent protection with configurable settings, enabling precise control of breaker trips for overload, short‑circuit, and earth‑fault conditions. The unit employs microprocessor technology for reliable and accurate detection, setting adjustment, and trip cause indication without the need for an external power supply. It supports integration with optional modules for remote monitoring and alarm signaling.
