Siemens 3VA1150-4EF36-0AC0 — 50 A MCCB with TM240 Release
The Siemens 3VA1150-4EF36-0AC0 is a 3-pole SENTRON molded case circuit breaker rated for 50 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release. It carries a 121 kA interrupting capacity at 240 V AC, dropping to 75.6 kA at 415 V and 52.5 kA at 440 V — numbers that matter when coordinating with downstream devices in a high-fault panel. The breaker holds its full 50 A rating up to 50 °C ambient; above that it derates linearly to 45 A at 70 °C, so a warm cabinet means you need headroom.
Breaking Capacity and Selectivity
The 121 kA at 240 V is the headline number, but the 75.6 kA at 415 V is the one that governs most industrial motor-control panels on 400 V three-phase. That's enough for full selectivity with most upstream SENTRON or 3WL air breakers in a typical distribution board — no need to oversize the main just to cover a 50 A feeder. At 690 V the capacity drops to 11.9 kA, so if you're on a 690 V mining or marine system, check the fault current at the point of installation.
Panel Integration and Mounting
The breaker measures 76.2 mm wide, 130 mm tall, and 70 mm deep — a standard 3-pole MCCB footprint that fits most DIN-rail or screw-mount panel layouts. The front face is IP40 rated, so it's fine for a clean indoor enclosure; no special gasket needed. Two HQ auxiliary switches (form C) are built in, giving you normally-open and normally-closed status contacts for PLC feedback or alarm annunciation without adding a separate accessory block.