Siemens 5SJ4120-7HG41 Miniature Circuit Breaker

Siemens SENTRON 5SJ4120-7HG41 is a one-pole miniature circuit breaker designed for 240 V AC circuits, delivering 20 A of protection with a Type C (curve C) tripping characteristic and a 14 kA breaking capacity. This UL 489‑listed device (D=70 mm) is intended for DIN-rail mounting in distribution panels, providing reliable short‑circuit protection for lighting and general outlets in compact residential or small commercial installations. Key electrical ratings include a Ui of 440 V isolation voltage, a maximum operating voltage of 240 V AC, and compatibility with supply voltages up to 400 V at 50/60 Hz. The unit is rated for one pole, protecting a single live conductor, and meets IP20 protection with connected conductors (IP40 in the handle range). The mechanical life is typically around 10,000 operating cycles, supporting durable daily use. With a compact depth of about 70 mm, the 5SJ4120‑7HG41 fits neatly in standard breaker enclosures and is compatible with other 5SJ4 family components for modular, scalable protection in small to mid-size panels.