What this 50 A MCCB delivers — and what the ratings mean for your panel
The Siemens SENTRON 3VA1150-5EF36-0DH0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current Iu of 50 A and a rated insulation voltage Ui of 800 V. The interrupting capacity scales with system voltage: 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 690 V — which means this breaker can handle high-fault utility feeds at lower voltages while still providing adequate interruption on 690 V industrial networks. The TM240 thermal-magnetic release gives a fixed thermal pickup at 50 A and a magnetic trip threshold of 240 A (4.8× Iu), so it clears moderate overloads thermally and short-circuit faults magnetically without needing an external trip unit. The 50 A rating holds flat from 40 °C up to 50 °C, then derates to 48 A at 55 °C, 47 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. If your panel ambient runs above 50 °C, the effective continuous current drops — size the load side accordingly. The operating temperature range spans -25 °C to 70 °C, with storage from -40 °C to 80 °C. This MCCB includes an undervoltage release (UVR) as the auxiliary release design, plus 2 auxiliary switches and 1 trip alarm switch (HQ version). The trip indicator is present, so you get local visual confirmation of a fault trip. The front face carries IP40 protection — suitable for dry indoor panel environments, but not for washdown or outdoor exposure.
Integration notes — panel fit and wiring
The breaker occupies a 76.2 mm width (3-pole), 130 mm height, and 70 mm depth — a standard SENTRON 3VA footprint that fits existing DIN-rail or mounting-plate layouts without re-drilling. The undervoltage release coil must be wired to a separate control voltage; verify polarity and suppression per the device manual. The auxiliary contact block (2 NO/NC + 1 alarm) shares the same mechanical travel as the main contacts, so status feedback to a PLC or safety relay is straightforward.