Siemens QJ3B125 Molded Case Circuit Breaker MCCB

Siemens QJ3B125 is a three-pole molded case circuit breaker (MCCB) rated for 125 A at 240 V AC, designed for bolt-on installation in Siemens panels that accept QJ series devices. It uses thermal-magnetic protection with separate long-time and instantaneous trip functions and provides 10 kA interrupting capacity at 240 V, making it suitable for branch-circuit protection of three-phase feeders and motors in commercial and industrial electrical distributions. The unit includes load-side lug terminals and is packaged as a non-interchangeable trip bolt-on MCCB within the QJ family, offering rugged molded-case construction for reliable protection where compact, field-installable protection is required. Typical applications include motor circuits, control panels, and feeders in 3-phase systems up to 125 A, balancing safety and reliability in equipment protection.