What the ratings mean for fit
The Siemens SENTRON 3VA1220-6MH32-0AJ0 is a 3-pole molded case circuit breaker (MCCB) rated for a continuous current of 200 A at 40 °C, with a thermal-magnetic TM120M overcurrent release designed specifically for starter protection — meaning it's tuned to handle motor inrush without nuisance tripping while still clearing a locked-rotor fault. The 200 A rating holds flat from 40 °C up to 50 °C, then derates linearly to 176 A at 70 °C, so if your panel ambient runs above 50 °C you need to account for the reduced ampacity. Breaking capacity is 220 kA at 240 V, 154 kA at 415 V, 75.6 kA at 440 V, 30 kA at 500 V, and 4.5 kA at 690 V — that's the maximum fault current the breaker can safely interrupt at each voltage level, which drives your SCCR coordination study. The insulation voltage is rated at 800 V, so it's suitable for 480/277 V and 600 V systems with headroom. The breaker includes 2 auxiliary switches plus 1 trip alarm switch as standard, which is enough for remote status feedback — one auxiliary for the breaker position, one for a control interlock, and the alarm for a separate fault indication circuit. There's no undervoltage release or ground-fault monitoring on this variant, so if you need those functions you'd look at a different suffix in the 3VA family.
Panel integration and mounting
Dimensions are 105 mm wide, 158 mm high, and 70 mm deep — that's a 4.13 x 6.22 x 2.76 inch footprint. The 3VA12 frame mounts on a DIN rail or can be screw-mounted to a backplate. The 70 mm depth is shallow enough for most 200 mm deep enclosures, but verify the gland plate clearance if you're running cables behind the breaker. The TM120M trip unit is field-replaceable, and the breaker accepts plug-in accessories (shunt trip, auxiliary switches) without removing the main body from the panel.
Compliance and documentation
As a SENTRON-series MCCB from Siemens, this breaker carries UL 489, CSA C22.2 No. 5, and IEC 60947-2 certifications. The manufacturer provides RoHS and REACH compliance declarations, along with a CE declaration of conformity for the European market. The 3VA family also has a comprehensive IEC/UL coordination study available from Siemens — useful for the site electrical engineer's selectivity analysis.