What this MCCB is and where it fits
The Siemens 3VA1140-4EF36-0BA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels and industrial switchgear. It carries a TM240 thermal-magnetic overcurrent release, meaning the thermal pickup is fixed at 40 A at 40 °C ambient, with magnetic trip factory-set to 240 A. Rated insulation voltage is 800 V, and the breaker is rated for 3-pole operation — standard for three-phase AC feeders up to 690 V line-to-line. The undervoltage release (UVR) is built in, so this unit will trip if control voltage drops below the dropout threshold; verify your coil supply matches the UVR rating before commissioning. Breaking capacity varies sharply with system voltage: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. At 690 V the 11.9 kA figure is the limiting case — confirm your available fault current at that voltage before specifying.
Thermal derating and panel integration
The breaker holds full 40 A rating from 40 °C through 50 °C ambient. Above 50 °C it begins to derate: 39 A at 55 °C and 60 °C, 38 A at 65 °C, 37 A at 70 °C. If your enclosure ambient runs above 50 °C, size the feeder for the derated value, not the nameplate 40 A. Physical footprint is 130 mm height, 76.2 mm width, 70 mm depth — a compact 3-pole MCCB that fits standard panel-mount cutouts. Maximum power loss at rated load is 13.3 W; factor that into your enclosure thermal budget, especially in sealed cabinets. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The storage limit governs handling and warehousing, not running conditions.
Lifecycle and sourcing reality
Because it is an active catalog item, the normal Siemens distribution channel carries it. We source and quote it to order against an RFQ; availability and current pricing are confirmed at quote time. No minimum commitment required for a single-line BOM fill.