What this MCCB is and what it protects
The Siemens SENTRON 3VA1150-3EF36-0KH0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection — meaning it guards feeders and branch circuits against overload and short-circuit, not motor or generator protection. Its rated continuous current Iu is 50 A, and it holds that rating from 40 °C up to 50 °C ambient; above that it derates to 48 A at 55 °C, 47 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. That thermal curve matters for a panel sitting near a heat source or in a non-climate-controlled enclosure — the 50 A rating is only valid up to 50 °C ambient.
Interrupting capacity — what the ratings mean for selectivity
This MCCB carries interrupting ratings that vary by system voltage: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 10.5 kA at 690 V. Those are the maximum fault currents it can safely interrupt at each voltage level. For a 415 V distribution board, the 52.5 kA figure gives headroom above typical utility fault levels (often 25–50 kA), so it coordinates well downstream of a larger upstream breaker or fuse. At 690 V the 10.5 kA rating is lower — check your available fault current if the breaker lands in a 690 V circuit.
Panel integration and auxiliary wiring
The 3VA1150-3EF36-0KH0 mounts in a standard panel footprint with a width of 76.2 mm, depth of 70 mm, and height of 130 mm. It ships with a shunt trip (STL) as the auxiliary release design — that is a voltage-triggered remote trip coil, not an undervoltage release. The auxiliary contact configuration is 2 auxiliary switches plus 1 trip alarm switch (HQ designation). The integrated auxiliary trip order code is 3VA9688-0BL33. Front protection is IP40, so it is suitable for a clean indoor panel but not for washdown or outdoor exposure.
Overcurrent release and ratings
The overcurrent release is a TM240 — a thermal-magnetic type with a 240 A frame rating, set for the 50 A continuous current. Rated insulation voltage Ui is 800 V. The breaker has a trip indicator and a latching endurance of 15,000 operations.