The Siemens 3VA2450-5MQ32-0AA0 is a SENTRON molded case circuit breaker (MCCB) designed specifically for motor protection, with a continuous current rating of 500 A at ambient temperatures up to 50 °C. Above that, the rating derates linearly: 477 A at 55 °C, 455 A at 60 °C, 432 A at 65 °C, and 410 A at 70 °C — so on a warm panel floor you lose nearly 20 % of the headline capacity. The interrupting rating is the other headline figure: 187 kA at 240 V AC, 121 kA at 415/440 V, 75.6 kA at 500 V, and 9 kA at 690 V. That 187 kA at 240 V means this breaker can be placed on a high-fault panel upstream of smaller branch devices without needing a current-limiting fuse ahead of it — it's self-protecting at that level. The 3-pole design is built for three-phase motor circuits. It includes phase-failure detection, ground-fault monitoring via summation current formation on the L-conductor, and a communication function — so it can report trip events and status back to a PLC or BMS over a bus interface (the specific protocol is not listed, but the presence of a comm slot means you can retrofit a module).
Sizing and Coordination
The short-time withstand is rated at 6 kA limited to 1 second, with an initial value of 100 A. That short-time rating governs selectivity with downstream breakers: if you need full discrimination up to 6 kA, the 3VA2450 holds in for that duration before tripping, letting a downstream device clear the fault first. The trip times are adjustable between 3 s and 13 s — set them to coordinate with motor starting curves (avoid nuisance trips on inrush) while still clearing a locked-rotor condition.
Panel Fit and Environment
Dimensions are 138 mm wide, 248 mm high, 110 mm deep — a standard 3-pole MCCB footprint that fits most DIN-rail or panel-mount enclosures. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Maximum power loss is 99 W — account for that heat in the enclosure thermal calculation, especially when multiple breakers are ganged.