Big Sale Square D Q1B390 – 90A 3 Pole Molded Case Circuit Breaker

Built for commercial applications, this 90A three-pole breaker delivers standard 10kAIC protection at 240VAC. It features thermal-magnetic trip technology for consistent long-time and instantaneous response. This unit installs into legacy Square D NQO and NQOB panelboards. For modern upgrades, it is replaced by the QOB390, which requires an SK5668 mounting kit to fit the older bus structure. The Visi-Trip indicator provides clear visual confirmation during a fault, reducing downtime.