The Siemens SENTRON 3VA1112-6MH32-0AE0 is a 3-pole molded case circuit breaker (MCCB) purpose-built for starter protection — meaning it's designed to sit ahead of a motor starter in a branch circuit, not as a main feeder breaker. Rated 125 A continuous at 40 °C with the TM120M thermal-magnetic release, it holds that full rating up to 50 °C before a gentle derate curve kicks in: 122 A at 55 °C, 120 A at 60 °C, 117 A at 65 °C, and 114 A at 70 °C. That thermal stability matters when the breaker is enclosed in a warm panel next to contactors and drives.
Interrupting capacity — what the ratings mean for panel coordination
The SCCR curve on this unit is the real selector: 220 kA at 240 V, 154 kA at 415 V, 75.6 kA at 440 V, and 7.5 kA at both 500 V and 690 V. At 240 V, that 220 kA rating covers virtually any utility-fault scenario in North American panels. The drop to 7.5 kA at 690 V is typical for a frame this size — it still clears most industrial fault levels at that voltage, but verify against your transformer's nameplate available fault current. The rated insulation voltage of 800 V gives headroom for 690 V systems.
Starter protection design — built-in auxiliary switch count
The starter protection designation means the magnetic trip curve is shaped for motor inrush — it rides through the start transient without nuisance tripping. This variant ships with the supplied basic switch 3VA11126MH320AA0 and carries 4 auxiliary switches HQ as standard. That's four form-C contacts for status feedback to the PLC or safety circuit, which typically saves buying a separate auxiliary block. No undervoltage release, no ground-fault monitoring, no communication function — this is a clean motor-branch breaker.
DIN-rail footprint and environmental range
Mounts on standard DIN rail. Dimensions: 70 mm depth, 76.2 mm width (3 in), 130 mm height (5.12 in) — the 3-pole width is the critical dimension for panel layout. Operating temperature range -25 °C to 70 °C, storage from -40 °C to 80 °C. Maximum power loss is 28.1 W at full load — factor that into enclosure thermal calculations.