What this MCCB is and what it does
The Siemens SENTRON 3VA1040-3ED32-0BH0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection in distribution panels. It carries a rated continuous current Iu of 40 A and a rated insulation voltage Ui of 800 V. The interrupting capacity reaches 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 7.5 kA at 690 V — these numbers govern the fault-current headroom at the point of installation. The TM210 thermal-magnetic release handles overload and short-circuit protection without electronic adjustment. An undervoltage release (UVR) is built in, so the breaker trips if control voltage drops below the dropout threshold — common in emergency-stop or safety-disconnect circuits.
Thermal derating and real-world current
The 40 A rating holds from 40 °C through 50 °C ambient. Above that it derates: 38.4 A at 55 °C, 37.6 A at 60 °C, 36.8 A at 65 °C, and 36 A at 70 °C. If the panel ambient runs hot — say, next to a drive cabinet or in a non-climate-controlled enclosure — size the load to the derated figure, not the nameplate 40 A. Operating range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.
Auxiliary contacts and trip alarm
The breaker ships with 2 auxiliary switches plus 1 trip alarm switch (HQ type). The trip alarm changes state only on a fault trip — not on manual switching — so it can feed a separate alarm input to a PLC or annunciator. The integrated auxiliary trip accessory carries order code 3VA9608-0BB11. No communication function or phase-failure detection is built in; this is a straightforward thermal-magnetic MCCB with no electronic trip unit.