What this MCCB is and what it protects
The Siemens 3VA1150-4GF42-0AA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. Four poles, rated 50 A continuous at 40 °C, with a TM240 thermal-magnetic overcurrent release — that means the thermal element handles overloads and the magnetic element clears short-circuits, no undervoltage release or ground-fault monitoring fitted on this variant. The interrupting ratings tell you where it can go: 121 kA at 240 VAC, 75.6 kA at 415 VAC, 52.5 kA at 440 VAC, and 11.9 kA at both 500 VAC and 690 VAC. Rated insulation voltage is 800 V. For a 50 A frame, those are high-interrupting numbers — it clears a fault without upstream coordination issues in most low-voltage switchgear.
Thermal derating and panel integration
At 40 °C, 45 °C, and 50 °C the breaker holds 50 A without derating. At 55 °C it drops to 49 A, at 60 °C to 48 A, at 65 °C to 46 A, and at 70 °C to 45 A — a 10 % reduction at the top of the operating range. Ambient operating range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Maximum power loss is 14.6 W. Dimensions are 130 mm height, 101.6 mm width, 70 mm depth. The 70 mm depth is the dimension that matters for enclosure depth clearance — standard 200 mm deep enclosures clear it easily, but shallow gland-plate layouts need checking against that 70 mm plus wiring space.