Siemens NSB BQ2B125 Miniature Circuit Breaker

Siemens NSB BQ2B125 is a 125-amp, two-pole molded‑case circuit breaker (MCCB) from the BQ family, designed for 120/240 VAC distribution panels that accept BQ devices. The part number BQ2B125 denotes a 2-pole unit intended to protect heavy‑duty circuits within commercial and larger residential electrical systems. It uses a thermal/magnetic trip mechanism to deliver reliable overload and short‑circuit protection and is compatible with Siemens low‑voltage panelboards and load centers designed for the BQ lineup. The two poles operate with a common‑trip design to disconnect both lines on a fault, helping to simplify safety and coordination with other devices in the same protection scheme. Typical applications include protecting feeders and branch circuits in service equipment, distribution panels, and subpanels where Siemens BQ MCCBs are specified, delivering 120/240 VAC protection for wiring and equipment in a single, standardized package.