Siemens JXD63S400 A - 400 A, 600 V, 3-Pole Bolt-On Circuit Breaker | AmpState

The Siemens JXD63S400A is a 400A, 600V, 3-pole bolt-on molded case circuit breaker engineered for dependable protection in panelboards and loadcenters. Built for demanding electrical environments, it delivers precise branch circuit overcurrent and short-circuit protection with a robust, vibration-resistant connection.

Key features designed to outperform everyday breakers include a secure bolt-on mounting that creates a rigid bus connection, minimizing movement and arcing in dynamic electrical installations. The thermal-magnetic trip unit provides stable, repeatable protection by responding to both overload conditions (thermal) and short-circuit events (magnetic), helping to prevent nuisance trips and equipment damage under real-world load fluctuations.

Why this breaker stands out

• Secure bolt-on mounting ensures a rigid, vibration-resistant bus connection for long-term reliability in panels and loadcenters.
• Thermal-magnetic protection delivers dependable response to both overloads and short circuits, maintaining consistent performance across temperature changes and electrical noise.
• 3-pole design ideal for three-phase systems, providing balanced protection in commercial and light industrial settings.
• 400A, 600V rating suits heavy feeders and main-lault protection requirements without compromising trip characteristics.
• OEM compatibility designed to align with matching Siemens OEM loadcenters and panelboards for a seamless, interchangeable fit.
• Versatile applications suitable for residential, commercial, and light industrial distribution where reliable branch-circuit protection is essential.

Applications and use cases

• Protect large feeders and main distribution paths in commercial panelboards and loadcenters.
• Upgrade or retrofit 3-phase electrical rooms in light industrial environments requiring robust overcurrent protection.
• Install as a reliable safety device in emergency electrical systems where stable trip performance is critical.

Technical specifications

• Manufacturer: Siemens
• Part Number: JXD63S400A
• Type: Thermal-magnetic molded case circuit breaker
• Amperage Rating: 400A
• Voltage Rating: 600V
• Number of Poles: 3
• Mounting Style: Bolt-on
• Application: Branch circuit overcurrent and short-circuit protection

Installation and best practices

For optimal performance, ensure mounting is solidly secured to the panelboard or loadcenter and that bus connections are clean and free of corrosion. Follow Siemens installation guidelines and verify compatibility with your specific OEM panelboard. When replacing a breaker, match the amperage, voltage rating, and pole configuration to maintain consistent protection characteristics and coordination with downstream devices.