Siemens Industry, Inc. QJ3B150 Circuit Breaker

The Siemens Industry, Inc. QJ3B150 is a 150-amp, three-pole molded‑case circuit breaker from the QJ Series, rated for 240 V AC in three‑phase service. It features a thermal‑magnetic trip with both long‑time and instantaneous trip functions and delivers 10 kA of short‑circuit interrupting capacity at 240 V, making it suitable for protecting feeders and equipment in industrial power distribution. This bolt‑on device provides line‑side and load‑side lug terminals with a non‑interchangeable trip, in line with the QJ3B family’s construction. As a model often cataloged as QJ3‑B150, this unit is considered obsolete by some distributors, though it may still be stocked for legacy installations. Typical applications include main‑disconnect or feeder protection in industrial panels powered by 240 VAC three‑phase systems where a 150 A protective device is required.