What this MCCB does for a 40 A feeder
The Siemens SENTRON 3VA2040-6KQ32-0KA0 is a 3-pole molded case circuit breaker rated 40 A continuous at up to 70 °C ambient — no derating needed across the full temperature band from 40 °C to 70 °C, all at 40 A. That flat thermal curve simplifies panel design: one frame size covers the same load regardless of where it sits in the enclosure. Breaking capacity is the headline: 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 3 kA at 690 V. At 415 V, that 187 kA SCCR handles most industrial transformer-fed fault levels without needing a current-limiting upstream device. The 3 kA at 690 V is a reminder this is a 600 V class frame — not for 690 V main feeders, but fine for 690 V motor circuits where the available fault current stays low. Insulation voltage is rated 800 V. The adjustable thermal-magnetic trip range is 16 A to 64 A, with a factory-set full-scale of 40 A. No undervoltage release is fitted, but a shunt trip (STL) is integrated for remote tripping via a control signal.
Panel fit and communication
Dimensions are 181 mm high, 105 mm wide, 86 mm deep. That 105 mm width is a standard 3-pole MCCB footprint — fits existing SENTRON mounting plates and busbar systems without adapters. The 86 mm depth leaves clearance for rear-connected accessories. A communication function is onboard, supporting integration with energy management or remote monitoring systems — useful for a panel that needs breaker status or load data on a bus. The supplied basic switch is 3VA20406KQ320AA0, confirming the internal mechanism.
Lifecycle and sourcing posture
Storage temperature range is -40 °C to 80 °C; operating range is -25 °C to 70 °C. Maximum power loss is 2.2 W — negligible for enclosure thermal calculations.
Ground-fault and auxiliary release details
Ground-fault monitoring uses summation current formation on the L-conductor — a residual-current method that detects leakage without a separate RCD module. The shunt trip (STL) allows a remote pushbutton, PLC output, or safety relay to open the breaker. No trip indicator is fitted, so remote indication depends on the communication function or auxiliary contacts.