What this MCCB is and what it does
The Siemens 3VA1220-6MH32-0DC0 is a SENTRON molded case circuit breaker (MCCB) configured for starter protection — a 3-pole unit rated for 200 A continuous current (Iu) with a TM120M thermal-magnetic release. The 'starter protection' designation means its trip curve is shaped to coordinate with motor contactors and overload relays, so it clears a bolted fault without letting the contactor weld shut. That 200 A holds flat from 40 °C through 50 °C; above 55 °C it derates to 192 A, then 188 A at 60 °C, 184 A at 65 °C, and 180 A at 70 °C — useful to know if the breaker lives in a hot enclosure near the motor starter.
Breaking capacity — what the numbers mean for selectivity
This MCCB carries 220 kA at 240 V, 154 kA at 415 V, 36 kA at 440 V, and 17 kA at 690 V. Those are the interrupting ratings at each voltage level — the current it can safely extinguish an arc at. In a 415 V distribution panel with a transformer upstream that can deliver 100 kA fault current, this breaker sits comfortably below its 154 kA ceiling, so no cascading failure if a downstream short occurs. At 690 V the 17 kA rating still covers most industrial motor-drive bus faults. No phase-failure detection or ground-fault monitoring on this variant; the trip logic is purely thermal-magnetic, which means no electronics to drift, but also no communication module or voltage trigger.
Mounting and panel fit
The breaker measures 105 mm wide, 158 mm high, 70 mm deep — a standard SENTRON 3VA frame size for 200 A. It mounts on a DIN rail or directly to a backplate via the screw terminals. The front face carries an IP40 rating, so it's protected against tools and wires >1 mm but not against water ingress; keep it inside a sealed enclosure in washdown areas. Two HQ (high-capacity) auxiliary switches are built in for status feedback to a PLC or safety relay.