Siemens JXD63B400 Three Pole 400A Circuit Breaker

Siemens JXD63B400 is a three-pole molded-case circuit breaker rated for 400 A at up to 600 V AC (600 V, 250 V DC), and designed on the JD frame as part of the Sentron JXD6 family, delivering 50/60 Hz operation. It uses a thermal-magnetic trip unit with a non-interchangeable trip mechanism for consistent overcurrent protection in industrial power systems. The breaker carries an interrupting rating of 25 kAIC at 600 V, with 35 kAIC at 480 V, enabling safe interruption of significant faults in three-phase networks. Commonly used to protect feeders, panelboards, motor control centers, and equipment circuits in manufacturing and processing facilities, it integrates with Siemens' molded-case breaker ecosystem and provides reliable, code-compliant protection across three phases. Operating voltage and current ratings align with common industrial standards, and the unit is designed for compatibility within Siemens' distribution panels where JD-frame breakers slot in alongside other Sentron devices. The JXD63B400 supports standard field installation in new builds or upgrades, enabling precise coordination with upstream protective devices and downstream devices for selective tripping. This model is documented in Siemens' data libraries and widely stocked by distributors, ensuring availability for service, maintenance, and regulatory compliance.