Siemens 3VA1150-4EF32-0AH0 — SENTRON MCCB, 50 A, 121 kA IC
The Siemens 3VA1150-4EF32-0AH0 is a SENTRON molded case circuit breaker (MCCB) built for line protection in distribution panels. Three poles, rated 50 A at 40 °C, with a TM240 thermal-magnetic release — that means fixed thermal and magnetic trip elements, no electronic adjustment. The interrupting capacity is the headline figure here: 121 kA at 240 V AC, which clears high-fault currents without cascading upstream breakers. Insulation voltage rated 800 V, so it handles 480 V and 600 V class systems comfortably. Rated current holds flat at 50 A from 40 °C through 50 °C ambient; it starts to derate above that — 49 A at 55 °C, 48 A at 60 °C, down to 45 A at 70 °C. That thermal curve matters for enclosed panels with limited airflow. Power loss at rated load is 14.6 W, a number to factor into the panel's thermal budget. Interrupting capacity drops with system voltage: 75.6 kA at 415 V, 52.5 kA at 440 V, 11.9 kA at 500 V and 690 V. The 121 kA at 240 V is the peak — typical for a 240/120 V delta or 277/480 V wye service entrance where the available fault current is high.
Integration — Panel Fit and Mounting
The 3VA1150-4EF32-0AH0 measures 70 mm deep, 76.2 mm wide, 130 mm tall — a standard MCCB footprint for DIN-rail or panel-mount installation in a distribution board. The 76.2 mm width (3 inches) is the pole pitch for a 3-pole breaker; it occupies three 1-inch module spaces on the rail. Auxiliary switch configuration is 2 aux switches plus 1 trip alarm switch (HQ type), which fits common status-monitoring needs without external relays.