Westinghouse LB3400F Molded Case Circuit Breaker

The Westinghouse LB3400F is a 3-pole, 400 A molded‑case circuit breaker designed for fixed‑mount, panel‑mounted installations in commercial and industrial electrical systems. This 600 V AC device belongs to the LB series and delivers overcurrent and short‑circuit protection for high‑capacity three‑phase circuits in switchgear assemblies, panelboards, motor control centers, and industrial electrical panels. Its thermal‑magnetic trip mechanism provides dependable fault interruption for branch circuits and equipment protection across manufacturing facilities, HVAC systems, industrial automation, and power distribution applications. The LB3400F is widely used as a replacement for aging protection devices and during electrical system upgrades and preventative maintenance. It is compatible with switchgear and distribution systems and is designed for commercial and industrial protection schemes, with a fixed mounting and molded‑case construction that supports reliable operation in demanding environments. Common replacements include Eaton LB3400F, Cutler‑Hammer LB3400F, and Square D LA36400.