Siemens Q21550CT2 Circuit Breaker

Siemens Q21550CT2 QT Quadplex Circuit Breaker is a 120/240 V molded‑case, plug‑in device that fits Siemens load centers that accept QT quadplex breakers. It packs four poles in a single 1/2-in per pole QT frame, configured as two 50 A poles and two 15 A poles to provide mixed‑circuit protection within one compact unit. The catalog number Q21550CT2 denotes a quadplex arrangement compatible with CTL QT panels and standard Siemens QT listings. It employs a thermal‑magnetic trip mechanism with long‑time and instantaneous trip functions to protect against overloads and short circuits, and it carries a 10 kA interrupting rating at 240 V. This breaker is designed for residential applications in Siemens QT panels that support quadplex units, offering space‑saving protection for multiple circuits without sacrificing compatibility or safety.