MCCB for high-fault panel builds
The Siemens SENTRON 3VA2040-8KQ32-0AA0 is a 3-pole molded case circuit breaker rated at 40 A continuous current (Iu) with an ETU860 electronic trip unit for line protection. Its interrupting capacity reaches 440 kA at 240 V and 330 kA at 415 V, which means it can safely clear faults up to those levels without upstream cascading — critical for high-available-fault-current switchboards where a standard MCCB would fail closed. The breaker carries an 800 V rated insulation voltage (Ui) and maintains its 40 A rating across the full ambient range from 40 °C to 70 °C — no derating needed for warm enclosures. The front face is IP40 rated, suitable for general indoor panel environments where tools or fingers are the primary intrusion risk. Communication function is built in, enabling integration with higher-level monitoring or energy-management systems without an external module. The ETU860 release supports ground-fault monitoring via summation current formation on the L-conductor, which is useful for detecting leakage in ungrounded or impedance-grounded systems.
Physical fit and panel integration
The breaker measures 105 mm wide by 181 mm high by 86 mm deep. It mounts on a DIN rail or directly to a backplate via the standard SENTRON 3VA footprint. The 3-pole width (105 mm) matches the common 3-pole MCCB slot in most distribution panels; verify the mounting hole pattern against your existing busbar or adapter kit before committing the BOM line.