The LV848594 is a front face shutter and locking block for the MasterPact MTZ3 drawout chassis, 4P configuration. It provides position indication and locking for the chassis, serving as a safety interlock that prevents racking the breaker into a live position when the shutter is closed.
This accessory locks the chassis, not the breaker itself. The drawout mounting means it integrates into the fixed chassis cradle where the MasterPact MTZ3 breaker slides in. The 4P designation matches the four-pole chassis opening. Position indication on the shutter tells the operator whether the breaker cradle is racked to connected, test, or disconnected positions before the shutter can be opened.
Deployment context
Installed in the drawout chassis of a MasterPact MTZ3 switchboard or motor control center. The locking block and shutter assembly is a safety-critical component that enforces the correct sequence for breaker insertion and removal — the operator cannot rack the breaker into the connected position unless the shutter is open, and the shutter locks the breaker in the test/disconnected position when closed.