The LV839301 is a Masterpact MTZ3 40 HF automatic switch disconnector rated 4000 A at 40 °C, 3-pole, drawout chassis mount. The integral instant protection of 170 kA is the let-through capability of the ArcBlok mechanism, not the withstand; it limits peak fault energy during the first half-cycle. Drawout mounting means the moving portion withdraws on telescoping rails for inspection or swap without unbolting line and load conductors — standard for main breakers in switchgear where uptime matters. Connection pitch is 9.06 in (230 mm) between phase centers, which matches standard low-voltage switchgear bus spacing.
Deployment context
This is a chassis-mount drawout device for low-voltage distribution switchgear — not a panelboard breaker. The 31.07 in (789.1 mm) width and 18.8 in (478.1 mm) height set the cutout and mounting footprint; verify the existing cradle or cell accommodates the MTZ3 frame before ordering. Depth of 16.8 in (426.8 mm) includes the extended position for drawout racking.