Siemens Q320 Three-Phase Plug-In Circuit Breaker

Siemens Q320 is a 240V, 20A three-pole plug-in circuit breaker from the QP family, designed for fast, tool-free installation in Siemens load centers and meter combos. This molded‑case breaker uses a thermal‑magnetic trip mechanism to provide reliable overcurrent protection for 3‑phase 240V circuits, with a 10 kAIC interrupt rating and UL 489 listing. As a Type QP device, it is intended for plug‑in installation and compatibility across Siemens QP/MP panels, enabling coordinated protection with other QP breakers in residential or light commercial distribution systems. The Q320’s three‑pole design makes it suitable for protecting 3‑phase feeders and motors fed from 240V circuits, while its compact plug‑in form reduces installation time and simplifies panel maintenance. In practice, it serves as the protective core for 3‑phase equipment in service panels that require a dedicated 20A, 240V breaker with standard thermal‑magnetic trip characteristics and a 10,000 AIC interrupt rating.