Schneider Electric QO390 Plug-In Circuit Breaker

Schneider Electric's QO390 plug-in circuit breaker is a 3-pole, 90-amp device designed for 240-volt three-phase service. As part of the Square D QO family, it is engineered for plug-in installation in compatible QO and QON load centers, NQ panelboards, and related Schneider Electric distribution panels. It carries a 10 kA interrupting rating, providing robust short-circuit protection for 240 VAC feeders, and is specified for 240 VAC, 3-phase operation. The QO390 uses a plug-in mounting arrangement that simplifies replacement in suitable enclosures, making it a standard choice for protecting larger 3-phase circuits in commercial or light industrial electrical systems. Catalog references consistently list the part as QO390, 90 A, 3-pole, 240 V, 10 kAIC, underscoring its role as a reliable 3-phase breaker for feeders and equipment up to 90 amps in Schneider Electric installations.