The Siemens SENTRON 3VA1150-4EE42-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated 50 A continuous at 40 °C, using a TM220 thermal-magnetic overcurrent release — meaning the thermal element handles overloads and the magnetic element handles short-circuits, no electronics to fail or program.
This breaker delivers 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V.
Thermal rating and ambient derating
Above that it derates linearly: 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, 45 A at 70 °C. The TM220 release is fixed, not adjustable, so the thermal curve is factory-set.
Four poles in a 101.6 mm wide package — that is about 25.4 mm per pole, standard for this frame size. Front IP40 protection means it is splash-proof from the front but not sealed; mount it in an IP54 or higher enclosure if washdown is present.