ABB PR221DS Three-Phase Molded Case Circuit Breaker

ABB PR221DS-LS/I is an electronic trip unit designed for Tmax three-pole molded‑case circuit breakers (frames T4–T6), delivering long-time, short-time, and instantaneous protection for three‑phase systems. The LS/I combination denotes long-time and short-time protection with instantaneous trip, and it is offered for frames that support In ratings from about 320 A to 1000 A, with observed examples including In=320 A, 400 A, 630 A, 800 A, and 1000 A, and a system voltage up to 690 V. This trip unit is intended to be used on motor control centers, switchboards, and other three‑phase distribution in industrial settings where precise overcurrent protection is required. As part of ABB's Tmax family, PR221DS-LS/I replaces traditional thermal‑magnetic protection with an electronic solution, aligning with modern protection schemes for heavy-duty MCCBs.