500 A MCCB with 187 kA SCCR — selectivity headroom for high-fault panels
The Siemens SENTRON 3VM1450-5MH32-0AA0 is a 3-pole molded case circuit breaker rated for continuous 500 A at 40 °C, with a maximum breaking capacity of 187 kA at 240 V AC and 121 kA at 415 V AC. That SCCR headroom means it can sit upstream of lower-rated branch breakers in a high-fault panel without cascading failure — the interrupting rating stays intact through a bolted fault at those voltages. The TM120M thermal-magnetic release provides fixed overload and short-circuit protection curves, so the trip characteristic is set at the factory — no field-adjustable dials to mis-calibrate. Rated insulation voltage is 800 V, which covers 480/600 VAC systems with margin for transient spikes.
Thermal derating and power dissipation — panel fill factor matters
The 500 A rating holds flat from 40 °C through 50 °C; above that it derates linearly to 452 A at 70 °C. In a sealed enclosure with other heat sources, the 120 W maximum power loss at rated load drives the ventilation or cabinet-size decision — a 500 A MCCB dumping 120 W into a small panel can raise internal ambient past the 50 °C knee if airflow is inadequate. Dimensions are 248 mm high, 138 mm wide, 110 mm deep. The IP40 front protection means the breaker face is protected against tools and wires >1 mm, but the enclosure back and sides rely on the panel's own IP rating — standard for switchboard mounting.
Sourcing and compliance documentation
This MCCB is sourced and quoted to order against an RFQ through independent distribution; availability and current pricing are confirmed at quote time. The manufacturer provides standard compliance documentation including RoHS, REACH, and IEC/UL certification data sheets for the SENTRON series — request these with your RFQ if they are not already on file.