Schneider Electric QOU140 U Single Pole Circuit Breaker

Schneider Electric's Square D QOU140 U is a 1-pole miniature circuit breaker rated for 40 A at 120/240 VAC, designed to protect a single branch circuit in residential or light-commercial panels. It employs a thermal-magnetic trip mechanism with an interrupting rating of 10 kA at 120/240 VAC and features field-reversible line/load lugs for installation flexibility. The device is part of the QOU family and supports DIN rail or surface mounting, accepting 14 to 2 AWG aluminum or copper conductors depending on termination options, with a compact footprint of 0.75 in (19 mm) wide by 2.63 in (67 mm) deep by 4.05 in (103 mm) high. It operates across typical indoor temperatures, rated from 14 to 140°F, and is suitable for 50/60 Hz service. This 40 A, 1-pole unit protects circuits such as lighting, receptacle runs, and small-appliance circuits in panels that accommodate QOU-type breakers, and it integrates with other QO/U family devices to provide coordinated overcurrent protection within a single electrical system.