What this MCCB is and what it does
The Siemens 3VA2450-5MN32-0JL0 is a SENTRON-series molded case circuit breaker (MCCB) in a motor-protection variant, rated for 500 A continuous current (Iu) across a 3-pole configuration. Its ETU350M electronic trip unit provides adjustable overload and short-circuit protection with phase-failure detection, making it a direct fit for motor branch circuits where standard thermal-magnetic breakers lack the precision or coordination flexibility needed.
Breaking capacity — what the numbers mean for your coordination study
This breaker carries a short-circuit breaking capacity of 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 17 kA at 690 V. That 187 kA figure at 240 V is the headline number for low-voltage fault duty — it tells you this frame can interrupt a fault up to that level without bursting, which matters when you're coordinating downstream with a transformer secondary or a high-capacity bus. At 690 V the 17 kA rating drops significantly, so verify your available fault current at that voltage before specifying.
Thermal derating and panel integration
The breaker is rated for full 500 A continuous current up to 50 °C ambient. Above that, it derates linearly: 495 A at 55 °C, 490 A at 60 °C, 485 A at 65 °C, and 480 A at 70 °C. If your panel ambient runs hot — say, a packed enclosure with drives — you need to account for that 20 A drop at 70 °C. The 138 mm width and 110 mm depth fit a standard MCCB footprint; plan for 99 W maximum power loss in your thermal budget.