Siemens HJXD63B400 - 400 A, 600 V, 3-Pole Bolt-On Circuit Breaker | AmpState

Siemens HJXD63B400 is a robust 400A, 600V, 3-pole bolt-on molded case circuit breaker designed to deliver dependable branch circuit overcurrent and short-circuit protection in panelboards and load centers. Its secure bolt-on mounting creates a rigid bus connection that resists vibration, helping maintain a solid, reliable electrical path even in demanding environments.

Powered by a thermal-magnetic trip unit, this breaker provides stable, repeatable protection performance. The thermal element protects against sustained overloads, while the magnetic element delivers instantaneous response to short circuits, helping to minimize damage to conductors and downstream equipment. This combination reduces nuisance trips in varying temperatures and load conditions, so your system remains protected when it matters most.

Engineered for seamless integration, the HJXD63B400 is compatible with matching Siemens OEM load centers and panelboards. This means straightforward replacements or upgrades without unwelcome fit issues or wiring changes, keeping installation efficient and reliable in the field.

Ideal for residential, commercial, and light industrial applications, this 3-pole breaker is well-suited for three-phase distribution and feeders that require reliable disconnection of all phases for safety. Use it to shield branch circuits serving motors, HVAC equipment, lighting, and other high-demand loads where consistent protection and quick fault clearing are essential.

Why choose the HJXD63B400? It combines high-current capability with robust mechanical design and precise thermal-magnetic protection, delivering predictable trips and steady performance across duty cycles. In panelboard upgrades or new installations, it provides a trusted solution for durable, code-consistent protection of critical feeders.

Applications and use cases

• Three-phase panelboards and load centers requiring 400A main or feeder protection
• Residential or light commercial electrical rooms with high-demand circuits
• Upgrading outdated protection in Siemens-compatible systems
• Motors, HVAC, and other demanding loads that benefit from fast magnetic-trip protection

Technical highlights

• Amperage rating: 400A
• Voltage rating: 600V
• Poles: 3
• Mounting style: Bolt-on
• Type: Thermal-magnetic molded case circuit breaker
• Application: Branch circuit overcurrent and short-circuit protection
• Manufacturer/Part: Siemens, HJXD63B400