Siemens HJG3B400L - 400 A, 3-Pole Circuit Breaker | AmpState

Meet the Siemens HJG3B400L — a robust 400 A, 3-pole molded case circuit breaker engineered to protect branch circuits in panelboards and loadcenters. With a thermal-magnetic trip unit, it delivers stable, repeatable protection against overcurrent and short circuits while maximizing panel space through its compact design.

• Compact molded case design — makes efficient use of panel space, helping you fit more protection in tight electrical rooms or crowded panels.
• Thermal-magnetic trip unit — provides precise, predictable response to both overload and short-circuit conditions, reducing nuisance trips and improving overall system reliability.
• OEM compatibility — designed to pair with matching Siemens loadcenters and panelboards for straightforward replacement, upgrade paths, and dependable performance consistency.
• Versatile installation — suitable for residential, commercial, and light industrial applications where robust 3-pole protection is required.

Technical Specifications

• Manufacturer: Siemens
• Part Number: HJG3B400L
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 400 A
• Number of Poles: 3
• Application: Branch circuit overcurrent and short-circuit protection

Ideal Use Scenarios

This 3-pole breaker is well suited for three-phase distribution in panelboards and loadcenters found in small to mid-sized commercial spaces, light industrial settings, and residential installations that employ three-phase service. It serves as a reliable main or subfeed protection device, enabling clean, organized panel layouts while ensuring consistent trip performance across operating conditions.

What Sets It Apart

Beyond basic specs, the HJG3B400L emphasizes long-term reliability in real-world environments. The combination of a compact form factor with a thermal-magnetic trip mechanism delivers dependable protection without sacrificing enclosure space, and its Siemens OEM compatibility simplifies upgrades or retrofits, reducing downtime and ballast between components. For technicians and facility managers, this means fewer compatibility surprises and a streamlined path to code-compliant, protected circuits.

Choosing the Siemens HJG3B400L means prioritizing durable, predictable protection for demanding panel configurations—while keeping installation practical and space-efficient. If you’re upgrading a panel or building out a three-phase distribution network, this 400 A, 3-pole molded case breaker provides the trusted performance you expect from Siemens.