The Siemens 3VA1150-4EF32-0AG0 is a SENTRON 3VA molded case circuit breaker (MCCB) for line protection, carrying a TM240 thermal-magnetic overcurrent release. Three poles, rated 50 A continuously at 40 °C, with the full current curve holding flat to 50 °C before a gentle derate to 45 A at 70 °C. The interrupting ratings are what matter for panel coordination: 121 kA at 240 V AC, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. Insulation voltage rated 800 V, so it slots into 480/277 V and 600 V distribution without a derate on the insulation side.
Physical fit and integration
Dimensions: 130 mm height, 76.2 mm width (3 in), 70 mm depth (2.76 in). Standard 3-pole MCCB footprint for panel mounting on a backplate or DIN rail adapter. The TM240 release is factory-set; no undervoltage release or shunt trip fitted on this variant (no voltage trigger, no communication module). It ships with one auxiliary switch and one trip alarm switch (HP type) pre-installed.
What the ratings mean for your panel
The 121 kA at 240 V is the short-circuit current rating (SCCR) at the lowest voltage — that's the worst-case fault current the breaker can interrupt without welding or rupturing. At 415 V the rating drops to 75.6 kA, still high enough for most industrial distribution. The 50 A continuous rating is the thermal current (Ith) at 40 °C ambient; the breaker carries the same 50 A up to 50 °C, then derates linearly to 45 A at 70 °C. Power loss at rated load is 14.6 W maximum — useful for thermal calculations in a sealed enclosure. Operating temperature range is -25 °C to 70 °C; storage range -40 °C to 80 °C.