Siemens NJG3B400 Circuit Breaker, 400A, 3-Pole, 600V

The Siemens NJG3B400 Circuit Breaker is engineered for industrial electrical service, maintenance, and replacement projects where dependable overcurrent protection matters. With a 400 A rating, 3-pole configuration, and a 600 V maximum, this breaker is built to withstand demanding environments while delivering precise shutdown control when faults occur.

Designed to align with Siemens gear and compatible switchgear when the part number is verified, the NJG3B400 streamlines part selection in ongoing maintenance or upgrade initiatives. Its robust construction supports continuous operation in manufacturing floors, utility rooms, and other industrial settings where uptime is critical.

Key specifications

• Manufacturer: Siemens
• Part Number: NJG3B400
• Product Type: Circuit Breaker
• Amperage: 400 A
• Poles: 3
• Voltage: 600 V

Ideal uses

• Industrial electrical service panels and distribution boards
• Motor control centers (MCCs) and feeder protection
• Replacement in legacy Siemens installations that require precise part-number compatibility
• Upgrades in facilities where a 400 A, 3-pole, 600 V protection device is called for

Why the NJG3B400 stands out

What sets this breaker apart is the explicit alignment between the NJG3B400 part number and its application requirements. By prioritizing part-number compatibility, it minimizes guesswork during replacements and upgrades, helping facilities maintain consistent protection characteristics across existing gear. This is especially valuable in environments where exact screw-terminal layouts, bus configurations, and trip characteristics must match the current installation.

Compatibility and installation guidance

Before installation, verify fit by cross-referencing the NJG3B400 part number with your equipment’s specifications and the system’s voltage and pole requirements. Ensure the enclosure, bus configuration, and conductor sizing support a 400 A, 3-pole device rated for 600 V. If you need confirmation on compatibility, send us your installation details and we’ll help ensure the right match for your application.

Need help matching a part number or confirming compatibility? Message us and we'll help.