Siemens | NGB1B125B | Circuit Breaker | 125A | 1-Pole | 347V | 25kA | Bolt-On

Siemens NGB1B125B is a bolt-on circuit breaker engineered for reliable overcurrent protection in 347V distribution systems. This 125A, 1-pole unit is designed for maintenance, retrofit, and replacement projects where exact specifications matter, ensuring you get a precise fit and consistent performance in Siemens-compatible panels. With a 25 kA interrupting capacity, it provides robust protection against short-circuit events in commercial or light industrial applications.

• 125 A, 1-Pole — compact, straightforward protection for single-series circuits.
• Bolt-On mounting — secure, vibration-resistant installation in compatible Siemens panels.
• 347 V rating — suitable for medium-voltage distribution environments that require this voltage class.
• 25 kA interrupting capacity — strong protection against high-energy faults, helping safeguard equipment and wiring.
• Part number NGB1B125B — use this reference to verify compatibility and exact specs with your panel.
• Ideal for retrofit and replacement projects where matching the original Siemens spec is essential for reliability and code compliance.

Why this matters — In electrical distribution, using the correct amperage, voltage rating, and interrupting capacity prevents nuisance trips while delivering dependable protection for feeders, motors, and branch circuits. The NGB1B125B is purpose-built to slot into Siemens bolt-on panels that require a 125A, 1-pole solution, reducing uncertainty during upgrades or service work.

Use cases and scenarios

• Replacing an aging breaker in a 347V Siemens panel where a 125A, 1-pole breaker is specified.
• Retrofit projects upgrading distribution circuits to handle higher fault protection without changing enclosure hardware.
• Maintenance intervals that call for exact-match components to maintain panel certification and warranty eligibility.

Installation and compatibility tips

Always verify fit and ratings against the panel’s documentation before ordering. Use the part number NGB1B125B as the primary reference for compatibility. Follow standard bolt-on mounting procedures per Siemens installation guidelines, and ensure conductor sizing and enclosure clearance meet applicable codes and standards.