What this MCCB delivers on the line
The Siemens SENTRON 3VA1050-4ED36-0BA0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection, carrying a 50 A rated current at 40 °C and holding that rating steady through 50 °C — it only begins to derate above 55 °C, dropping to 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. That thermal curve means it can sit in a warm panel without losing headroom until ambient pushes past 55 °C. Breaking capacity is the real differentiator here: 121 kA at 240 V AC, 75.6 kA at 415 V, 52.5 kA at 440 V, and a solid 11.9 kA all the way up to 690 V. That 121 kA figure at 240 V tells you this breaker handles high-fault industrial feeds — not just branch circuits. The insulation voltage is rated 800 V, so the internal clearance is built for 690 V systems with margin.
Panel fit and integration
At 70 mm deep, 76.2 mm wide, and 130 mm tall, this MCCB fits standard 3-pole MCCB panel cutouts. The depth is the dimension to watch when routing bus bars behind the breaker — 70 mm leaves room for rear-connected buswork without forcing a deeper enclosure. Width at 76.2 mm (3 inches) lines up with common DIN-rail adapter plates or direct screw-mount patterns.
Undervoltage release and protection design
This unit ships with an undervoltage release (UVR) as the auxiliary release — designated as a TM210 overcurrent release design. The UVR trips the breaker when supply voltage drops below a set threshold, which is standard for motor feeder protection where a brownout could stall a load. No ground-fault monitoring module is integrated; that would be a separate accessory. Maximum power loss is 17.1 W, so factor that into enclosure thermal calculations if you're packing multiple breakers in a small cabinet.