What it is and what it does
The Siemens SENTRON 3VA1140-4EF36-0KH0 is a 3-pole molded case circuit breaker (MCCB) designed for line protection in distribution panels. It carries a continuous current rating of 40 A at 40 °C ambient, with a 121 kA interrupting capacity at 240 V AC — that's the short-circuit current it can safely clear without welding contacts or rupturing the case. The 800 V rated insulation voltage means it's built for 480/600 V class systems with headroom.
Breaking capacity across voltages
Interrupting rating drops as voltage rises: 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V (–). That 11.9 kA at 690 V is the limiting figure for high-voltage industrial feeds — if your fault current exceeds that at the higher voltage, you need a larger frame or upstream current-limiting fuse. The 121 kA at 240 V covers most commercial secondary-side applications.
Thermal derating and ambient limits
Rated 40 A from 40 °C through 50 °C ambient (–). At 55 °C it derates to 39 A, at 65 °C to 38 A, and at 70 °C to 37 A (–). Operating ambient range is -25 °C to +70 °C (–). If this breaker sits in a non-conditioned enclosure near a heat source, use the 37 A figure at 70 °C for your load calculation — don't spec it at the 40 A nameplate.
Auxiliary and release configuration
Comes with 2 auxiliary switches plus 1 trip alarm switch (HQ type), and a shunt trip release (STL). The shunt trip allows remote tripping via a control voltage — useful for emergency-stop circuits or interlocking with a fire-suppression panel. No undervoltage release and no ground-fault monitoring on this variant. No communication module — it's a standalone breaker, not a power-monitoring node.
Dimensions and panel fit
Width 76.2 mm (3 in), height 130 mm (5.12 in), depth 70 mm (2.76 in) (–, –). That's a standard 3-pole MCCB footprint for a 40 A frame — fits most DIN-rail or panel-mount enclosures without re-drilling. The 70 mm depth is the body only; allow extra for the shunt trip wiring and auxiliary switch terminals.