What this MCCB carries and where it fits
The Siemens 3VA1150-3EF36-0AE0 is a SENTRON molded case circuit breaker (MCCB) rated for 50 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release — fixed thermal and magnetic trip, no adjustment. It is a 3-pole unit built for line protection, meaning it sits at the feeder or main distribution point in a panel, not downstream on a specific machine load. Breaking capacity is the headline selector here: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 10.5 kA at 690 V. That 75.6 kA at 240 V gives you headroom for high-fault utility feeds or transformer secondaries where the available short-circuit current is substantial. At 415 V the 52.5 kA still covers most industrial distribution boards without a current-limiting fuse upstream. The TM240 release is non-adjustable — what you see is what trips. If your coordination study calls for adjustable long-time or short-time pickup, this is not the variant; you would step to the electronic release versions in the 3VA family. The fixed curve simplifies ordering and panel documentation but locks you into one trip characteristic.
Thermal derating and panel integration
The 50 A rating holds flat from 40 °C through 50 °C ambient. Above that it derates: 48 A at 55 °C, 47 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. If the panel internal temperature runs hot — say a sealed enclosure with multiple heat sources — size the continuous load against the 45 A floor at 70 °C, not the 50 A nameplate. Dimensions are 130 mm height, 76.2 mm width (3-pole), 70 mm depth. The 76.2 mm width is the standard 3-pole MCCB footprint — it occupies three 25.4 mm (1-inch) mounting slots on the DIN rail or panel-mount plate. The 70 mm depth leaves clearance for rear-connection busbars or cable ladders behind the panel door. IP40 on the front means tools or fingers cannot reach live parts, but the enclosure is not sealed against water ingress. Suitable for indoor panel mounting (Type 1 or Type 2 enclosures); not for washdown or outdoor exposure without a secondary enclosure.
Auxiliary contacts and lifecycle
This unit ships with 4 auxiliary switches (HQ type) integrated — two form-C (changeover) contacts typically used for status feedback to a PLC or for trip indication to a remote annunciator. The HQ designation indicates high-rupturing-capacity contacts suitable for switching control transformer or relay coil loads without welding. Mechanical endurance is rated at 15,000 operations (latching endurance). That is standard for a distribution MCCB — not a switching device for frequent motor starts, but fine for infrequent manual isolation or automatic breaker reclosing schemes. If your application cycles the breaker daily, consider a contactor or a dedicated switching MCCB with higher endurance.
Rated insulation voltage and compliance scope
Rated insulation voltage (Ui) is 800 V, which covers 690 V systems with margin. The breaking capacity at 690 V is 10.5 kA — sufficient for most 690 V industrial networks (mining, marine, wind) where the fault level is typically below 10 kA. For 690 V applications, verify the available fault current at the point of installation does not exceed 10.5 kA. The product reference code per DIN EN 81346-2 is Q (switching device). This is a standard designation for circuit breakers in industrial electrical schematics and helps with consistent labeling in panel documentation.