125 A MCCB with TM240 release — panel integration note
The Siemens 3VA1112-3EF32-0AF0 is a 3-pole SENTRON molded case circuit breaker rated for 125 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release. It is configured for line protection — no undervoltage release, no ground-fault monitoring, no communication module. The auxiliary contact package is 1 auxiliary switch plus 1 trip alarm switch (HQ type), which gives you both a status mirror and a separate fault indication contact for the PLC or annunciator panel. Breaking capacity is voltage-dependent: 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 covers most low-voltage distribution panels in North American and European 400 V class systems. The 75.6 kA at 240 V figure is high enough for transformer-fed main breakers in commercial gear. Thermal derating is published from 40 °C through 70 °C: the breaker holds full 125 A up to 50 °C, then steps down to 120 A at 55 °C, 117.5 A at 60 °C, 115 A at 65 °C, and 112.5 A at 70 °C. If the panel ambient runs hot — say a non-ventilated enclosure near a furnace line — use the 55 °C or 60 °C column for your load schedule.
Footprint and mounting
Dimensions are 70 mm deep, 76.2 mm wide, 130 mm tall. That 76.2 mm width is a standard 3-pole MCCB footprint — three 25.4 mm pole pitches — so it drops into the same DIN-rail or panel-mount cutout as other 125 A frame breakers. Front IP40 rating means it is protected against tools and wires >1 mm, but not against water ingress; keep it inside the enclosure.