Current Ratings and Thermal Derating
Above that, the rating steps down: 241 A at 55 °C, 232 A at 60 °C, 222 A at 65 °C, and 213 A at 70 °C. This derating curve matters when the breaker is enclosed in a warm panel — the actual load must stay under the derated value at the panel's internal temperature, not the nameplate 250 A.
The interrupting rating varies with system voltage: 187 kA at 240 V, 121 kA at both 415 V and 440 V, 75.6 kA at 500 V, and 4.5 kA at 690 V. This voltage-dependent curve is typical for MCCBs — the arc extinction energy changes with voltage, so the same breaker clears higher fault currents at lower voltages.
The 140 mm width for a 4-pole frame is standard for SENTRON 3VA2 breakers — it occupies three 45 mm pole-width slots plus one neutral pole. Mounting is via screw terminals or busbar connection; the breaker accepts lug or fork-type connectors. Verify the busbar pitch and terminal clearance against your panel layout before ordering.