What this MCCB is and what it carries
The Siemens SENTRON 3VA2440-7HL32-0CH0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection — the main disconnect and fault interrupter between your transformer or bus and the downstream distribution. It carries a continuous current rating of 400 A across the full ambient range from 40 °C to 70 °C, so you don't lose capacity as the panel warms up in summer. The adjustable thermal-magnetic trip unit covers 600 A minimum to 4800 A maximum, letting you dial the instantaneous pickup to match the inrush of motor loads or the fault tolerance of feeder cables without swapping the breaker body. Interrupting capacity is the headline here: 330 kA at 240 V, 242 kA at 415/440 V, 187 kA at 500 V, and 9 kA at 690 V. That 330 kA figure means it can clear a bolted fault on a large low-voltage transformer secondary without the arc re-striking — a spec that keeps the upstream switchgear from having to interrupt the full fault.
Built-in auxiliaries and releases
This variant ships with an undervoltage release (UVR) and a complement of 2 auxiliary switches plus 1 trip alarm switch HQ. The UVR drops the breaker if control voltage falls below a set threshold — standard for emergency-stop circuits and safety disconnects where loss of control power must open the main contacts. A mechanical trip indicator gives a visible flag when the breaker has opened on fault, so a tech walking the line can spot a tripped unit without opening the door.
Physical fit and panel integration
The breaker measures 138 mm wide, 248 mm tall, and 110 mm deep — a standard MCCB footprint that fits most 600 V switchgear buckets and panelboard mounting bases. The 110 mm depth means it clears typical gland plates and rear-mounted bus bars without interference. Power loss is rated at 66 W maximum — relevant for thermal calculations inside a sealed enclosure; you'll want to account for that heat load if the panel is NEMA 12 or 4X with limited convection. Operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C. The 70 °C operating ceiling matches the continuous-current derating table (flat 400 A all the way up), so no need to upsize for a hot electrical room.