Siemens 3VA1150-5EF32-0AB0 SENTRON MCCB, 50A, 187kA at 240V

It carries a 50 A continuous rating at 40 °C ambient and holds that rating steady up to 50 °C — no derating needed in a warm enclosure — then drops to 45 A at 70 °C. That thermal curve means you can size it for a 50 A feeder and still have headroom if the panel runs hot. Breaking capacity is what sets this MCCB apart: 187 kA at 240 VAC, 121 kA at 415 V, and 75.6 kA at 440 V. At 500 V and 690 V it still handles 17 kA, which covers most industrial 480/600 V services. The overload curve is set for line protection (cable/feeder), not motor protection, so don't use it as a motor starter protector unless you have separate overloads downstream. Dimensions are 130 mm high, 76.2 mm wide, 70 mm deep — standard 3-pole MCCB footprint that fits most Siemens SENTRON mounting bases and busbar systems.