SENTRON 3VA1 MCCB for line protection
The Siemens 3VA1050-4ED36-0DA0 is a SENTRON 3VA1 molded case circuit breaker (MCCB) designed for line protection — the primary feeder or distribution branch in a 3-phase panel. It carries a 50 A continuous rating at 40 °C through the TM210 thermal-magnetic release, which handles overload and short-circuit trip curves without external control power. The 121 kA breaking capacity at 240 V AC means it can safely interrupt high-fault currents on a low-voltage service entrance or subfeed, protecting downstream equipment from arc-flash damage.
Thermal derating and breaking capacity by voltage
The 50 A rating holds flat from 40 °C to 50 °C, then derates to 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. If the panel ambient runs above 50 °C, size the load at the derated value — not the nameplate 50 A. Breaking capacity drops with system voltage: 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. At 690 V the 11.9 kA figure governs; verify the available fault current at the installation point against that curve.
Integration: DIN-rail footprint and included undervoltage release
This MCCB snaps onto a standard DIN rail. Dimensions: 130 mm height, 76.2 mm width (3 in), 70 mm depth (2.76 in). The 3-pole body fits a standard 3-module panel space. The unit ships with an integrated undervoltage release (UVR) — when control voltage drops below the dropout threshold, the UVR trips the breaker open, preventing automatic reclosure on a brownout or power loss. No separate UVR module to wire; the release is factory-installed and tested.