125 A MCCB with TM240 trip — active line protection
The Siemens 3VA1112-3EF36-0KH0 is a SENTRON molded case circuit breaker (MCCB) rated for line-protection duty with a continuous current Iu of 125 A at 40 °C, holding that rating through 50 °C before beginning a gentle thermal derating curve — 120 A at 55 °C, 117.5 A at 60 °C, 115 A at 65 °C, and 112.5 A at 70 °C. The TM240 thermal-magnetic trip unit provides fixed overload and short-circuit protection without electronic adjustment, which simplifies specification and eliminates configuration risk on the panel floor. Breaking capacity runs 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 10.5 kA at 690 V — high enough for most industrial service-entrance or feeder applications where the available fault current is known and documented.
Panel fit and auxiliary wiring
Three-pole footprint: 76.2 mm wide, 130 mm tall, 70 mm deep — standard SENTRON 3VA1 form factor that drops into existing DIN-rail or screw-mounted panel layouts without re-drilling. The breaker ships with a factory-fitted auxiliary contact block carrying two auxiliary switches plus one trip-alarm switch (HQ configuration), which covers status feedback and remote tripping indication without an add-on order. A built-in shunt trip release (STL) is included for remote undervoltage or emergency-off circuits; the integrated auxiliary trip order code is 3VA9688-0BL33. No undervoltage release, no communication module, no ground-fault monitoring on this variant — it is a pure line-protection breaker with a hardwired trip coil.
Environmental and compliance profile
Operating temperature range spans -25 °C to 70 °C; storage range extends from -40 °C to 80 °C. Front-face protection is IP40. Rated insulation voltage Ui is 800 V.