Siemens 3VA1150-4EF36-0JA0 — 50 A SENTRON MCCB with Shunt Trip
The Siemens 3VA1150-4EF36-0JA0 is a 3-pole SENTRON molded case circuit breaker (MCCB) rated 50 A at 40 °C, designed for line protection in commercial and industrial distribution panels. It carries a 121 kA interrupting capacity at 240 V, dropping to 75.6 kA at 415 V and 11.9 kA at 690 V — the breaking curve tells you where this breaker is most effective: it handles high fault currents on lower-voltage secondary sides of transformers, not high-voltage motor circuits. The TM240 thermal-magnetic release provides fixed thermal and magnetic trip settings for overload and short-circuit protection. A shunt trip (STL) auxiliary release is built in, allowing remote tripping from a PLC or emergency-stop circuit — no undervoltage release here, so the breaker stays latched on control power loss unless the shunt is explicitly fired.
Breaking Capacity and Thermal Derating
Rated uninterrupted current holds at 50 A from 40 °C through 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 your panel ambient runs above 50 °C, size the continuous load at 45 A — the breaker won't nuisance-trip on a warm day. Maximum power loss is 14.6 W per pole — three poles total about 44 W dissipated inside the enclosure. In a sealed, uncooled panel with multiple breakers, that heat adds up; account for it in the thermal budget.
Panel Integration and Mounting
Width 76.2 mm (3 in), height 130 mm (5.12 in), depth 70 mm (2.76 in). Three-pole footprint matches the standard SENTRON 3VA mounting pattern — screws onto the backplate or mounts on a DIN rail adapter (not included). The 70 mm depth leaves clearance for rear-connected busbars or cable lugs in a 200 mm deep enclosure. Operating temperature range -25 °C to 70 °C; storage from -40 °C to 80 °C. Rated insulation voltage 800 V — suitable for 480/277 V and 600 V delta systems with margin.