The ABB E4S3200 PR121/P‑LSIG is a high-capacity low-voltage air circuit breaker from ABB’s Emax E4S series. It is equipped with a PR121/P‑LSIG electronic trip unit, providing adjustable protection against overloads, short-time currents, instantaneous short circuits, and ground faults. The breaker is suitable for use in industrial and commercial switchgear as a main distribution breaker or feeder protection. Its design allows for robust fault clearing and reliable protection of three-phase power distribution systems.