What this MCCB carries — and what that means for your panel
The Siemens SENTRON 3VA1110-4EF36-0HH0 is a 3-pole molded case circuit breaker rated for 100 A continuous current (Iu) at 40 °C, with a TM240 thermal-magnetic overcurrent release. The interrupting ratings tell the story: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at 690 V. That 121 kA at 240 V means it can safely clear a fault on a high-capacity transformer secondary without the arc flashing over — critical for main or feeder positions where available fault current is high. The 75.6 kA at 415 V covers most European industrial distribution panels. The 11.9 kA at 690 V is adequate for motor control centers on 690 V networks, but you'll want to verify it against your transformer's impedance and the point-of-common-coupling fault level. The line protection version means this MCCB is configured for cable and busbar protection rather than motor protection — no adjustable overload class, no phase-failure detection. It's a straightforward thermal-magnetic curve for feeder circuits. The TM240 release is fixed thermal and magnetic, not electronic, so coordination studies are simpler but less flexible than the electronic versions in the same 3VA family. The auxiliary contact block is factory-fitted: 2 auxiliary switches plus 1 trip alarm switch (HQ). That gives you position indication for open/closed and a separate contact that closes only on a trip event — useful for remote alarm annunciation or PLC input without extra wiring. The shunt trip (STL) is integrated as the auxiliary release design, meaning a remote signal can trip the breaker for emergency stop or interlock schemes. The specific shunt trip module is 3VA9688-0BL30.
Thermal derating — the real-world current you get
This MCCB holds its full 100 A rating up to 50 °C ambient. Above that, it derates: 96 A at 55 °C, 94 A at 60 °C, 92 A at 65 °C, and 90 A at 70 °C. If your panel runs hot — say, a non-ventilated enclosure near a furnace line or in a tropical climate — you lose 10 A by 70 °C. That's a 10% reduction, enough to nuisance-trip a fully loaded feeder. Factor the actual enclosure ambient into your load calculation, not just the nameplate 100 A. The operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The storage limit is for handling and warehousing, not running. IP40 on the front means it's protected against tools and wires >1 mm, but not against water ingress — keep it inside a rated enclosure.