What this MCCB is and what it protects
The Siemens SENTRON 3VA1150-4EF36-0CA0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current of 50 A at 40 °C and delivering interrupting capacities of 121 kA at 240 VAC and 75.6 kA at 415 VAC. It includes an undervoltage release (UVR) as the auxiliary release, which trips the breaker if supply voltage drops below a set threshold — a standard requirement for motor branch circuits and safety interlock schemes where a loss of control voltage must open the load.
Interrupting ratings and thermal derating
The SCCR curve spans 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 — the step-down above 500 V tells you the arc chamber is optimized for the 240–480 V range where most industrial MCCB applications sit. Thermal derating is minimal through 50 °C (full 50 A), then drops 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 the derated figure, not the 40 °C nameplate.
Panel fit and footprint
The MCCB measures 130 mm high, 76.2 mm wide, and 70 mm deep — a standard 3-pole SENTRON footprint that drops into existing DIN-rail or screw-mount panel layouts without re-drilling. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C — the storage floor matters if the breaker sits in an unheated warehouse before commissioning.