What this 125 A MCCB carries — and what it doesn't
The Siemens 3VA1112-3EF36-0BH0 is a 3-pole SENTRON molded case circuit breaker rated 125 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release. It holds 125 A flat from 40 °C through 50 °C, then derates to 120 A at 55 °C, 117.5 A at 60 °C, 115 A at 65 °C, and 112.5 A at 70 °C — so in a warm panel you lose about 10 % of headroom by the top of the operating range. 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 — a steep drop above 415 V, so if your fault current is high on a 480 V or 690 V system, check the coordination study against the 32 kA or 10.5 kA limit before committing the BOM line. No communication module, no phase-failure detection, no ground-fault monitoring — this is a straight line-protection MCCB with an undervoltage release (UVR) and a 2-auxiliary + 1 trip-alarm switch block (HQ version). The integrated auxiliary trip uses order code 3VA9608-0BB11 if you need to add a shunt or UVR later.
Panel fit and integration
Dimensions: 70 mm deep, 76.2 mm wide, 130 mm tall. Front protection is IP40 — fine for a dry enclosure, not for washdown. Rated insulation voltage Ui is 800 V. Latching endurance is 15 000 operations. The reference code per DIN EN 81346-2 is Q.