Siemens BQD320 is a three‑pole bolt‑on molded‑case circuit breaker rated at 20 A for 277/480 VAC systems, designed for panelboard installation in commercial and industrial distributions. It provides thermal‑magnetic overcurrent protection with a 14 kA interrupting rating at 480 VAC and carries UL 489, CSA‑C22.2, and IEC 60947‑2 certifications for use in certified panelboards. The unit uses lug‑in/out connections and supports typical conductors such as 12–6 AWG aluminum or 14–6 AWG copper, and is specified for operation at 50/60 Hz in environments up to 40°C.
