125 A MCCB with high interrupting capacity for line protection
The Siemens SENTRON 3VA1112-6EF36-0DA0 is a 3-pole molded case circuit breaker rated for 125 A continuous current, built for line protection in distribution panels. Its TM240 thermal-magnetic release handles overload and short-circuit protection without an electronic trip unit — straightforward, no configuration needed. Interrupting capacity hits 220 kA at 240 V, 154 kA at 415 V, 75.6 kA at 440 V, and still 17 kA at 690 V — so it clears high-fault scenarios downstream of large transformers or in industrial mains without cascading failure upstream. That kind of SCCR headroom means you can use it as a main breaker in a panel feeding multiple subfeeds, not just a branch device. Thermal derating is published from 40 °C through 70 °C: it holds 125 A up to 50 °C, then drops 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, size the breaker to the derated value, not the nameplate. An undervoltage release (UVR) is integrated — order code 3VA9608-0BB25 for the auxiliary trip — so the breaker drops out on loss of control voltage, which is common in safety circuits or emergency-stop chains that need a shunt trip on undervoltage. No auxiliary contact module is fitted as standard.
Panel fit and integration
Dimensions are 70 mm deep, 76.2 mm wide, 130 mm tall — a standard 3-pole MCCB footprint that drops into most SENTRON distribution panels and switchboard cubicles without re-drilling. Front IP40 means it is protected against tools and small wires, but not sealed against washdown; keep it inside a rated enclosure. Rated insulation voltage is 800 V, so it is suitable for 480/277 V and 600 V nominal systems with margin. Operating temperature range is -25 °C to 70 °C; storage from -40 °C to 80 °C.