Siemens Q21515CT2U Quadruple Pole Circuit Breaker

Siemens Q21515CT2U is a QT-type quadplex molded‑case circuit breaker designed for use in Siemens load centers. It combines a 15 A, 2‑pole common‑trip section with two additional 15 A, single‑pole sections in a single 4‑pole QT unit, providing four protected poles in a compact plug‑in package. Rated for 120/240 V AC, the device carries a 10 kA interrupting capacity (10,000 AIC), making it suitable for residential and light‑commercial panelboards that require reliable short‑circuit protection across mixed voltages. The Q21515CT2U is intended for plug‑in installations in QT‑series panels and assemblies that accept quadplex breakers, offering individual protection for each pole while enabling one 240 V circuit and two 120 V circuits within the same breaker assembly. This Siemens part is commonly used where space is at a premium in distribution panels, supporting two hot legs for a 240 V circuit and two separate 120 V branch circuits in a single quadplex unit.