What this MCCB does in a panel
The Siemens 3VA1450-7MH32-0AA0 is a 3-pole molded case circuit breaker (MCCB) from the SENTRON family, rated 500 A continuous and designed for starter protection — meaning it's built to handle motor inrush and coordinate with contactors and overload relays in a motor control center. The TM120M thermal-magnetic release gives you fixed thermal pickup and magnetic trip settings; no adjustment knobs to mis-set on the line. Breaking capacity is 440 kA at 240 V AC, 242 kA at 415 V, and 154 kA at 500 V — enough headroom for most industrial service-entrance or distribution positions where fault current is high. At 690 V it still clears 17 kA, so it's usable on 690 V line-ups if the available fault stays under that. Power loss runs 122.7 W max at rated load — that's heat that has to leave the enclosure. In a sealed panel with other breakers, factor that into your thermal budget.
Current derating and ambient limits
This breaker holds full 500 A up to 50 °C ambient. Above that it derates linearly: 488 A at 55 °C, 476 A at 60 °C, 464 A at 65 °C, 452 A at 70 °C. If your panel runs hot, you don't lose much — only about 10% at the top end — but don't plan on 500 A in a 65 °C switchroom without checking the curve. Operating temperature range is -25 °C to 70 °C; storage from -40 °C to 80 °C. The IP40 front protection keeps dust out of the mechanism but it's not sealed for washdown — keep it inside the enclosure.
Dimensions and panel fit
Footprint is 138 mm wide, 248 mm tall, 110 mm deep. That's a standard 3-pole MCCB cutout for this frame size — it fits existing SENTRON 3VA mounting bases and busbar kits without re-drilling. Depth of 110 mm means it clears most 200 mm-deep enclosures with room for wiring behind it.