MCCB with high interrupting capacity for line protection
The Siemens 3VA1050-4ED42-0KA0 is a SENTRON 4-pole molded case circuit breaker rated for 50 A continuous current (Iu) with a TM210 thermal-magnetic overcurrent release. It is configured for line protection — no undervoltage release, no ground fault monitoring, no auxiliary contacts, and no communication module. The interrupting ratings are the headline: 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 numbers mean it can clear a bolted fault at the main distribution board without upstream fuses needing to open — selectivity headroom for the panel designer.
Current derating and thermal limits
Rated 50 A at 40 °C, 45 °C, and 50 °C — no derating in that band. At 55 °C it drops to 48 A, at 60 °C to 47 A, at 65 °C to 46 A, and at 70 °C to 45 A. The operating temperature range is -25 °C to 70 °C; storage from -40 °C to 80 °C. If the panel ambient runs above 50 °C, the breaker still carries 45 A at the top end — useful for a hot enclosure.
Physical fit and mounting
Dimensions: 70 mm deep, 101.6 mm wide, 130 mm tall. Front protection is IP40 — sealed against tools and small wires, not washdown. The breaker includes a shunt trip release (STL) and a voltage trigger; the integrated auxiliary trip is order code 3VA9688-0BL33. No auxiliary contact version is fitted, and there is no N-conductor protection. For DC network applications, the 3VA molded case circuit breaker device manual covers the specifics.