MCCB for line protection — 125 A continuous, 121 kA SCCR at 415 V
The Siemens 3VA1112-5EF32-0DA0 is a SENTRON molded case circuit breaker (MCCB) rated for line-protection duty. It carries 125 A continuously at 40 °C ambient and holds that rating through 50 °C before a linear derate to 114 A at 70 °C. The 3-pole frame is fitted with a TM240 thermal-magnetic release — the thermal element handles overloads on a time-current curve, the magnetic instantaneous element clears short-circuits. At 415 V the interrupting capacity is 121 kA; at 240 V it reaches 187 kA. That SCCR headroom means this breaker can be installed at high-fault locations without cascading upstream — useful when the transformer is close or the service entrance feeds a dense MCC lineup. The 800 V rated insulation voltage and the undervoltage release (UVR) option make this MCCB suitable for 400/480 V distribution panels where loss-of-voltage protection is required by code or machine safety schema. The UVR drops the breaker when control voltage falls below dropout threshold — no separate shunt-trip wiring needed for emergency-stop circuits that must fail to a safe state.
Footprint and panel integration
The MCCB measures 70 mm deep by 76.2 mm wide by 130 mm tall. The 3-pole width is standard for a 125 A frame in the SENTRON family — it occupies three adjacent 25.4 mm pole positions on a DIN rail or panel-mount base. No communication module or ground-fault monitoring is fitted on this variant, so the wiring compartment stays uncluttered; the UVR coil terminals and line/load lugs are the only connections. Power loss at full load is 30.6 W maximum, which should be factored into enclosure thermal calculations if the panel is densely packed.