Siemens AG B2125 Miniature Circuit Breaker MCB

Siemens B2125 is a two-pole miniature circuit breaker (MCB) rated for 125 A in 120/240 V AC circuits, providing automatic disconnection to protect wiring and devices in Siemens low-voltage distribution systems. It is commonly used in residential and light commercial panels to interrupt fault currents on branch circuits, helping prevent insulation damage and fire hazards while integrating with standard Siemens panel architectures. This model is part of Siemens’ B-series family of MCBs, with bolt‑on variants carrying the B2125H designation for secure mounting in compatible enclosures; the family is designed to deliver reliable thermal‑magnetic protection in typical distribution applications. For replacement in aging installations, the B2125 offers a straightforward, two‑pole solution that aligns with Siemens accessories and replacement parts designed for Siemens panels and distribution boards.