What this MCCB is and where it fits
The Siemens SENTRON 3VA1150-4EF32-0KH0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection in commercial and industrial distribution panels. It carries a rated current of 50 A across the 40 °C to 50 °C ambient range, with slight derating above that — 49 A at 55 °C, down to 45 A at 70 °C. The insulation voltage is rated 800 V, and the unit handles a maximum power loss of 14.6 W. It ships with a factory-fitted shunt trip (STL) release and a complement of 2 auxiliary switches plus 1 trip alarm switch (HQ configuration). The basic switch supplied is order code 3VA11504EF320AA0.
Breaking capacity — what the numbers mean for your fault duty
This breaker's interrupting capacity varies sharply with system voltage, which is typical for MCCBs. At 240 V it can clear 121 kA — plenty for most low-voltage service entrances. At 415 V it's rated 75.6 kA, at 440 V it drops to 52.5 kA, and at 500 V and 690 V it holds at 11.9 kA. The 11.9 kA figure at 690 V is the limiting factor: if your panel's available fault current exceeds that at the higher voltage, you need a current-limiting upstream device or a higher-rated frame. For a 480 V system (common in North America), the 52.5 kA at 440 V is the closest published point and suggests substantial headroom for most installations.
Panel fit and integration
The breaker measures 130 mm high, 76.2 mm wide, and 70 mm deep. It mounts on a DIN rail or directly to a panel backplate via the standard SENTRON 3VA footprint. The 3-pole design occupies three modular width units (each ~25.4 mm). The shunt trip (STL) and auxiliary switch block are pre-installed, so no field assembly of accessories is needed — just wire the line and load lugs, connect the shunt trip control voltage, and land the auxiliary contacts into your PLC or status indication circuit. The trip indicator and voltage trigger are built in.