What this MCCB is and what it does
The Siemens 3VA2040-8KQ46-0AA0 is a SENTRON molded case circuit breaker (MCCB) sized for line protection in distribution panels. Its 40 A continuous rating holds flat from 40 °C through 70 °C — no derating curve to chase across the typical panel ambient range, which simplifies the BOM entry for a 40 A feeder. Four poles cover three-phase-plus-neutral or dual-feed configurations. The ETU860 electronic trip unit provides adjustable overload and short-circuit protection with communication capability, so this breaker can report status and trip events back to a building management or SCADA system. Breaking capacity runs 440 kA at 240 V, 330 kA at 415/440 V, 220 kA at 500 V, and 52.5 kA at 690 V — high enough for most transformer-fed main or feeder positions without cascading upstream fuses.
Mounting and integration
At 140 mm wide, 181 mm tall, and 86 mm deep, this MCCB fits standard panel-mount cutouts for 4-pole SENTRON 3VA devices. The IP40 front face suits indoor distribution boards; no washdown rating, so keep it inside the enclosure. Rated insulation voltage is 800 V, and the operating temperature range spans -25 °C to 70 °C, with storage from -40 °C to 80 °C. That covers unheated electrical rooms and most industrial environments.