Siemens 5SJ4118-7HG42 Circuit Breaker

Siemens SENTRON 5SJ4118-7HG42 is a one-pole miniature circuit breaker (MCB) in the NSJ family, rated for 440 V AC with a nominal 15 A current rating and a 14 kA short‑circuit breaking capacity. It uses a thermal‑magnetic trip mechanism with a Class C trip curve, designed to protect against overloads and short circuits in circuits that experience moderate inrush currents. As a 1‑pole device within the SENTRON 5SJ4 line, it provides single‑phase overcurrent protection for electrical distribution panels and enclosures operating at 440 V, commonly used in commercial and light industrial installations. The model designation 5SJ4118-7HG42 specifies the 1‑pole, 15 A, 14 kA interrupt capacity, and 440 V compatibility, and the device is UL 489 listed as part of Siemens’ miniature circuit breaker family. Applications include protecting lighting circuits, receptacle runs, and small loads within 440 V distribution networks where fast interruption of fault currents is essential.