Siemens HJXD63B350 - 350 A, 600 V, 3-Pole Bolt-On Circuit Breaker | AmpState

Meet the Siemens HJXD63B350—a robust 350-amp, 600-volt, 3-pole bolt-on molded case circuit breaker (MCCB) built to safeguard panelboards and loadcenters from overcurrent and short-circuit events. Designed for dependable, long-term performance in residential, commercial, and light industrial environments, this breaker blends heavy-duty protection with straightforward installation.

• Secure bolt-on mounting—provides a rigid, vibration-resistant connection to the bus bar, reducing the risk of loose contacts in busy electrical rooms and equipment racks.
• Thermal-magnetic trip unit—delivers stable, repeatable protection by combining a thermal element for time-delayed overloads with a magnetic element for instantaneous short-circuit trips.
• 3-pole design for true 3-phase protection—copies and protects all three phases simultaneously, ensuring coordinated disconnection and safer downstream equipment.
• 600V rated performance—suitable for modern commercial distribution and light industrial systems that demand reliable high-voltage protection.
• High current capacity—350A rating makes it ideal for feeder circuits, main disconnects, or critical branch circuits within Siemens-compatible panels.
• OEM compatibility—designed to pair with matching Siemens loadcenters and panelboards for straightforward upgrades, replacements, or panel refurbishments.

Why choose this breaker for your panel?

When you’re protecting demanding electrical layouts, you need a device you can trust to stay seated, perform predictably, and respond precisely when fault conditions appear. The HJXD63B350’s bolt-on construction minimizes vibration-induced contact issues, while the thermal-magnetic trip system provides nuanced protection that reduces nuisance trips without compromising safety. Its 3-pole framework ensures synchronized disconnection across all phases, helping maintain system integrity in three-phase installations.

Ideal use cases

• Upgrading or replacing components in Siemens OEM panelboards and loadcenters
• Feeder protection for commercial electrical rooms and light industrial equipment
• Residential-to-light-commercial panel upgrades where higher current protection is required
• Installations where vibration resistance and reliable trip performance are priorities

Technical snapshot

• Manufacturer: Siemens
• Part Number: HJXD63B350
• Type: Thermal-magnetic molded case circuit breaker (MCCB)
• Amperage Rating: 350A
• Voltage Rating: 600V
• Number of Poles: 3
• Mounting Style: Bolt-on
• Application: Branch circuit overcurrent and short-circuit protection

Equip your panel with a breaker that blends rugged mechanical design with precise, reliable electrical protection. The Siemens HJXD63B350 is ready to help you deliver safer, more resilient power distribution in commercial and industrial settings—backed by compatibility with Siemens’ own panel ecosystems and a proven track record of dependable performance.