Siemens | NEB2B125B | Circuit Breaker | 125A | 2-Pole | 600V | 35kA | Bolt-On

Siemens NEB2B125B is a rugged, bolt-on 2-pole circuit breaker engineered for demanding electrical environments. With a 125A rating and 600V maximum operating voltage, it delivers dependable protection for feeders and branch circuits in commercial and industrial panels. Its 35kA interrupting capacity provides a strong safety margin for fault events, helping to safeguard both equipment and personnel.

Key specifications at a glance

• Amperage: 125A
• Poles: 2-Pole
• Voltage: 600V
• Interrupting Capacity: 35kA
• Mounting: Bolt-On
• Part Number: NEB2B125B

What sets the NEB2B125B apart

Designed for durability, this Siemens circuit breaker uses a bolt-on mounting style to deliver a secure, vibration-resistant connection inside compatible panels. The bolt-on configuration supports reliable seating and reduces the risk of loose contacts in environments with frequent movement or vibration—an important advantage in industrial installations and retrofit projects.

Ideal use cases

• Maintenance and retrofit projects where exact panel compatibility is essential
• Replacement of failed or aging breakers in commercial/industrial switchgear
• 125A feeder protection for 600V circuits in panels that require bolt-on devices
• Service equipment upgrades in warehouses, manufacturing lines, data centers, and other facilities

Compatibility and installation guidance

For best results, confirm fit and ratings before ordering. The NEB2B125B part number is the most reliable reference for compatibility with Siemens panels designed for bolt-on protection devices. Before installation, verify:

• That your panel supports 2-pole, 125A bolt-on breakers
• The system voltage is suitable for 600V and the application requires up to 35kA interrupting capacity
• Correct mounting method and electrical clearances as specified by the panel’s documentation

During installation, follow standard electrical safety practices, refer to your panel’s torque and connection guidelines, and ensure that the conductors and lug connections are properly tightened to manufacturer specifications.

Why choose Siemens for protection needs

Siemens brings a long track record of reliability in power distribution. The NEB2B125B embodies this heritage with precise engineering and compatibility within Siemens’ bolt-on catalog, making it a dependable choice when you’re protecting critical circuits and planning future replacements or upgrades.