What this MCCB delivers for your panel
The Siemens 3VA1150-3EF36-0BA0 is a 3-pole SENTRON molded case circuit breaker rated for 50 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release. The TM designation means it combines a thermal bimetal element for overload protection with a magnetic coil for short-circuit response — no electronic trip unit, so no auxiliary power needed for the trip function. Breaking capacity runs 75.6 kA at 240 V, 52.5 kA at 415 V, and 32 kA at 440 V, which covers most industrial distribution panels and motor branch circuits in North American and European voltage systems. The 50 A rating holds flat from 40 °C through 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 — relevant if you are packing this into a high-density enclosure with limited airflow. This version is configured as line protection (not motor or generator protection), so the TM240 release curve is set for general distribution feeder or branch-circuit duty. It ships without auxiliary contacts or a communication module — if you need remote status feedback or a shunt trip, those are add-on accessories (the integrated auxiliary trip order code is 3VA9608-0BB11). The front face carries an undervoltage release (UVR) as standard, which drops the breaker on loss of control voltage — a common requirement for safety disconnects or emergency-stop chains.
Physical fit and mounting
Dimensions are 70 mm deep, 76.2 mm wide, and 130 mm tall — a compact 3-pole footprint that fits standard DIN-rail or panel-mount enclosures. The 76.2 mm width (roughly 3 inches) matches the typical 3-pole MCCB slot in a distribution board. Front IP40 protection means the breaker face is sealed against tools and solid objects larger than 1 mm, but not against moisture — mount it in a dry indoor panel or add a higher-rated enclosure if washdown is present.
Selectivity and coordination notes
The 50 A TM240 release gives a fixed thermal pickup at roughly 1.05× to 1.25× Iu and a magnetic trip threshold at 240 A (4.8× Iu for the TM240 designation). For selective coordination downstream of a larger MCCB or upstream of a 50 A feeder, the 75.6 kA interrupting rating at 240 V provides headroom against high-fault conditions without cascading. The 800 V rated insulation voltage (Ui) covers 480Y/277 V and 600 V delta systems with margin. If you are coordinating with a 3VA1112-5EF32-0CA0 or similar sibling, the key difference is the frame size and release type — this 3VA1150 uses a 50 A frame with TM240, while the 3VA1112 uses a 125 A frame with a different electronic or thermal-magnetic curve. Do not assume drop-in interchange without checking the mounting hole pattern and busbar spacing.