The Westinghouse FB3040 Bolt-On Molded Case Circuit Breaker is a 40 A, 600 V, three‑pole device designed for bolt‑on installation in industrial power distribution panels. Part of the FB Frame family, it uses thermal-magnetic protection for overcurrent and short‑circuit protection on 3‑phase circuits operating at 50/60 Hz. This breaker is commonly employed in motor control centers, switchboards, and industrial control panels to protect motors, conveyors, HVAC infrastructure, and automation equipment; common replacements include Eaton FB3040, Siemens HFB3040, and Square D FA3440.
