What this MCCB is and where it fits
The Siemens 3VA1150-4EF36-0HC0 is a SENTRON molded case circuit breaker (MCCB) built for line protection — the primary feeder or branch protection role in a distribution panel. It carries a continuous current rating of 50 A at 40 °C, with minimal thermal derating up to 70 °C (45 A at 70 °C). That makes it a fast mover for standard 50 A feeder circuits in commercial and light industrial switchboards. Three poles, 800 V rated insulation voltage, and interrupting ratings that step from 121 kA at 240 V down to 11.9 kA at 690 V. The 121 kA at 240 V covers high-fault service-entrance positions on 240/120 V split-phase or 208Y/120 V systems; the 75.6 kA at 415 V handles most 400 V-class industrial distribution. At 690 V the 11.9 kA still clears faults on 600 V-class motor control centers.
Built-in trip unit and auxiliary hardware
The breaker ships with a shunt trip (STL) release and two factory-fitted HQ auxiliary switches. The shunt trip lets a remote PLC or emergency-stop circuit force the breaker open — typical for safety interlocks on conveyor feeders or pump panels. The two auxiliary switches provide status feedback (open/closed) to a DCS or indicator lamps, with no extra wiring module needed. No undervoltage release is installed on this variant. Power loss at full load is 14.6 W — relevant for thermal budgeting inside a sealed enclosure. The breaker is 76.2 mm wide, 130 mm tall, 70 mm deep, so it fits a standard 3-pole MCCB footprint on a DIN rail or panel-mount base.