What this MCCB is and what the ratings mean for fit
The Siemens 3VA1220-5MH32-0AC0 is a SENTRON molded case circuit breaker (MCCB) in the starter protection version, meaning it's built to handle motor-starting inrush without nuisance tripping — the TM120M thermal-magnetic release is tuned for that duty cycle. Rated continuous current Iu is 200 A, and it holds that full rating from 40 °C up through 50 °C; above that it derates to 192 A at 55 °C, 188 A at 60 °C, 184 A at 65 °C, and 180 A at 70 °C. If your panel ambient runs hot, the 200 A frame still gives you headroom at the lower end of the derate curve. Interrupting capacity is the headline here: 187 kA at 240 V, 121 kA at 415 V, 30 kA at 440 V, and 17 kA at 690 V. That 187 kA at 240 V tells you this breaker can sit on a high-fault panelboard or a transformer secondary without needing a current-limiting fuse upstream — it clears a bolted fault at that level on its own. The 3-pole, 3-phase form factor is standard for motor branch circuits. It ships with 2 auxiliary switches HQ (high-quantity contact configuration) built in, so you get status feedback to the PLC or annunciator without adding a separate aux block. Latching endurance is rated at 15,000 operations — that's the mechanical life under load; for motor starting duty it'll outlast most contactors in the same cabinet.
Panel fit and mounting
Dimensions are 105 mm wide, 158 mm high, 70 mm deep — a standard 3-pole MCCB footprint for a 200 A frame. It mounts on a DIN rail or direct-panel bolted; the IP40 front protection means the breaker face is sealed against tools and fingers, but the enclosure around it needs to handle the rest of the ingress protection. Rated insulation voltage Ui is 800 V, so it's comfortable on 480 V and 600 V class systems with margin.