Siemens CJD63L400 - 400 A, 600 V, 3-Pole Bolt-On Circuit Breaker | AmpState

Meet the Siemens CJD63L400 — a 400A, 600V, 3-pole bolt-on molded case circuit breaker built to shield panelboards and loadcenters from overcurrent and short circuits. From AmpState, this unit pairs industrial-grade reliability with a practical, easy-install design for demanding electrical installations.

Why this breaker stands out

• Secure bolt-on mounting delivers a rigid, vibration-resistant bus connection that stays tight under panel activity, reducing the risk of loose contacts and arc faults.
• Thermal-magnetic trip unit provides stable, repeatable protection by combining thermal sensing for overloads with magnetic sensing for instantaneous short-circuit response, maintaining shielded circuits across temperature variations.
• Three-pole configuration supports balanced protection for three-phase systems, making it well-suited for commercial and light industrial applications while also accommodating residential 3-phase setups.
• OEM-compatible design is engineered to be compatible with matching Siemens OEM loadcenters and panelboards, ensuring proper form, fit, and electrical coordination.

Ideal applications and use cases

Designed for branch circuit protection, the CJD63L400 excels in service upgrades, panelboard modernization, and new installations where a robust 3-pole, 400A breaker is required. It’s appropriate for residential, commercial, and light industrial environments where reliable protection and durable construction matter most.

Key specifications

• Manufacturer: Siemens
• Part number: CJD63L400
• Type: Thermal-magnetic molded case circuit breaker
• Amperage rating: 400 A
• Voltage rating: 600 V
• Number of poles: 3
• Mounting style: Bolt-on
• Application: Branch circuit overcurrent and short-circuit protection

Practical guidance and benefits

Choosing a bolt-on MCCB like the CJD63L400 helps ensure long-term panel reliability in environments with frequent vibration or movement. The bolt-on connection minimizes bus-bar looseness, while the thermal-magnetic trip unit delivers predictable protection across a wide range of operating conditions. This minimizes nuisance trips during startup surges and keeps critical loads protected during faults.

If you’re updating panelboards or adding a main feeder in a three-phase system, the CJD63L400 provides a proven, compatible solution that aligns with Siemens' engineered ecosystem. Its 400A rating makes it suitable for substantial distribution needs without compromising on safety or performance.