Siemens NSB-Q230 Miniature Circuit Breaker

Siemens NSB-Q230 Miniature Circuit Breaker is a two‑pole, 30‑amp, 120/240‑V MCB designed for residential and light‑commercial panels. It uses thermal‑magnetic trip protection with a 10,000‑A interrupting rating to shield circuits from overloads and short circuits, and it fits the Siemens QP/MP family on an EQ 125‑A frame for plug‑in installation in compatible load centers. The Q230 supports standard 120/240‑V loads and is UL 489 listed; many variants include INSTA‑WIRE termination for quicker field wiring. Its compact footprint measures about 2.0 in high, 3.0 in wide, and 2.3 in deep, enabling installation in typical Siemens distribution panels. Typical applications include protecting branch circuits for lighting, outlets, and small‑appliance circuits, as well as feeders in residential panels where a 30‑A two‑pole protection is required.