What this MCCB is and what it does
The Siemens SENTRON 3VA1140-5EF36-0KH0 is a 3-pole molded case circuit breaker (MCCB) rated at 40 A continuous at 40 °C, designed for line protection in distribution panels and industrial switchboards. Its 187 kA breaking capacity at 240 V AC means it can safely interrupt very high fault currents — typical for large transformer secondaries or close-coupled busway feeds — without the breaker failing open or cascading the fault upstream. The breaker carries a shunt trip (STL) auxiliary release and a complement of 2 auxiliary switches plus 1 trip alarm switch (HQ configuration), giving the controls engineer remote status and emergency-trip capability without adding external relays. Rated insulation voltage is 800 V, and the unit dissipates 10.8 W maximum at rated load — a figure to consider for enclosure thermal budgeting when packing several breakers in a single panel.
Breaking capacity across voltage — where it fits
The interrupting rating drops sharply as system voltage rises: 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at both 500 V and 690 V. At 690 V the 17 kA SCCR is modest — verify the available fault current at the installation point before committing this breaker to a 690 V bus. At 240 V and 415 V, the headroom is generous for most commercial and light industrial services.
Thermal derating and ambient limits
The breaker holds its full 40 A rating from 40 °C through 50 °C, then derates to 39 A at 55–60 °C, 38 A at 65 °C, and 37 A at 70 °C. Operating ambient range is -25 °C to +70 °C; storage range is -40 °C to +80 °C. If the panel ambient runs above 50 °C, size the upstream conductor and downstream load for the derated value, not the nameplate 40 A.
Physical fit and panel integration
Dimensions are 70 mm depth, 76.2 mm width, 130 mm height — a standard 3-pole MCCB footprint that fits Siemens SENTRON mounting bases and most DIN-rail adapter plates. The 76.2 mm width (3 inches) matches the typical 3-pole module spacing in distribution panelboards.