Breaking capacity — what the numbers mean for panel coordination
The 3VA1140-4EF32-0AF0: This MCCB delivers 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 690 V. Those are the interrupting ratings at each system voltage — the breaker can safely clear a fault up to those levels without welding contacts or rupturing the case. For a 40 A frame, 121 kA at 240 V is a high-interrupting-capacity variant, meaning it can sit downstream of a transformer or large bus without needing a current-limiting fuse upstream. At 690 V the 11.9 kA rating is still adequate for most industrial motor circuits, but verify against the available fault current at the point of installation.
Thermal derating and ambient temperature
The breaker holds its full 40 A rating from 40 °C through 50 °C ambient. Above that, derating applies: 38.4 A at 55 °C, 37.6 A at 60 °C, 36.8 A at 65 °C, and 36 A at 70 °C. If the panel ambient runs hot — say inside a non-ventilated enclosure near other heat sources — use the 55 °C or 60 °C column to size the continuous load. The operating temperature range is -25 °C to +70 °C, with storage from -40 °C to +80 °C.
Physical fit and panel integration
Dimensions: 130 mm height, 76.2 mm width, 70 mm depth. The 76.2 mm width is a standard 3-pole MCCB footprint — three modules at 25.4 mm each — so it fits existing SENTRON 3VA panel cutouts and busbar systems. Front IP40 protection (tools and wires won't reach live parts from the front). The breaker has no undervoltage release, no shunt trip, no ground-fault module, and no communication function; it is a standalone thermal-magnetic protector with auxiliary contacts for status feedback.