What this MCCB is and what it does
The Siemens SENTRON 3VA2225-6JQ32-0BC0 is a 3-pole molded case circuit breaker (MCCB) rated for 250 A continuous current at 40 °C, designed for line protection in industrial distribution panels. Its adjustable thermal-magnetic trip covers a range from 375 A minimum to 2 500 A maximum, letting you dial in the protection curve to match downstream cable and load. Breaking capacity is 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 4.5 kA at 690 V — so it handles high-fault utility feeds at common low-voltage levels while still clearing a 690 V motor circuit. The 86 mm depth and 105 mm width fit standard MCCB panel footprints; the 181 mm height leaves room for busbar connections above and below.
Thermal derating and operating limits
The 250 A rating holds flat from 40 °C through 50 °C. Above that, derate to 238 A at 55 °C, 225 A at 60 °C, 213 A at 65 °C, and 200 A at 70 °C. If your panel ambient runs hot — say, next to a drive cabinet or in a non-climate-controlled enclosure — size the upstream conductor and bus for the derated current, not the nameplate 250 A. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Maximum power loss at rated load is 50.5 W, which matters for enclosure thermal rise calculations.
Built-in auxiliary and undervoltage release
This variant ships with two auxiliary switches (HQ design) and an undervoltage release (UVR). The UVR trips the breaker when control voltage drops below a set threshold — standard for emergency-stop circuits or undervoltage protection on motor feeders. The auxiliary switches provide status feedback (open/closed) to a PLC or indicator lamp without needing a separate contactor block. Communication function is present, so it can integrate with a higher-level monitoring system via the SENTRON bus.