63 A MCCB with undervoltage release — what the ratings mean for your panel
The Siemens SENTRON 3VA2163-6HN32-0CA0 is a 3-pole molded case circuit breaker (MCCB) rated for 63 A continuous current across the full ambient temperature range from 40 °C to 70 °C — no derating needed as the panel warms up, which simplifies the thermal coordination study on a crowded DIN-rail section. Breaking capacity hits 242 kA at 240 V and stays at 187 kA through 440 V, then drops to 121 kA at 500 V and 3.7 kA at 690 V. That 242 kA figure at 240 V means this breaker can interrupt a fault upstream of a large transformer without the arc flashing over — critical for a main service entrance where the available fault current is high. The built-in undervoltage release (UVR) trips the breaker when supply voltage drops below a set threshold, protecting downstream loads from brownout damage. It's wired into the control circuit, not the power path, so the release coil draws minimal current — roughly the same as a small relay coil.
Panel fit and integration
At 105 mm wide, 181 mm tall, and 86 mm deep, this MCCB occupies three standard 35 mm DIN-rail modules. The 86 mm depth leaves clearance behind a 120 mm deep enclosure backplate — common for wall-mounted distribution boards. Line protection design means the internal trip curve is shaped for cable and busbar protection, not motor overload. If you're feeding a motor directly, put a separate overload relay downstream.