Square D QOB3401021 Miniature Circuit Breaker

Square D by Schneider Electric QOB3401021 is a 3-pole molded‑case circuit breaker in the QOB bolt‑on line, rated 40 A for 120/240 VAC circuits. It is designed for bolt‑on mounting in compatible QOB panel boards and enclosures and uses a thermal‑magnetic trip mechanism to provide overload and short‑circuit protection for three‑phase feeders. The unit offers a 10 kA interrupt rating at 240 VAC, indicating the maximum fault current it can safely interrupt. It is available with a 120 V shunt‑trip option for remote tripping, making it suitable for safety interlock and emergency shutdown applications in commercial or light industrial settings. This 3P 40A breaker aligns with Square D’s QO/QOB family, ensuring compatibility with QOB panels and other components while delivering reliable overcurrent protection for three‑phase circuits in 120/240 VAC service environments.