What it is and what it does
The Siemens 3VA1140-3EF36-0DH0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. It's a 3-pole unit rated 40 A continuous with a trip indicator and an undervoltage release (UVR) — the UVR drops the breaker if supply voltage falls below a set threshold, which matters for motor starters or safety circuits that need to prevent automatic restart after a brownout. The breaking capacity is 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 11.9 kA at both 500 V and 690 V — that range covers most industrial low-voltage distribution grids. At 40 A continuous it doesn't derate until 55 °C (39 A at 55 °C, 38 A at 65 °C, 37 A at 70 °C), so it holds rating in a warm panel up to about 50 °C ambient.
Panel fit and wiring
Dimensions: 70 mm deep, 76.2 mm wide, 130 mm tall. The 76.2 mm width is three standard 25.4 mm pole pitches — it drops into a typical MCCB cutout or DIN-rail adapter plate without panel modification. The 70 mm depth leaves room behind a 200 mm deep enclosure door for wiring and the auxiliary switch block. The breaker ships with a built-in undervoltage release (UVR) and provisions for 2 auxiliary switches plus 1 trip alarm switch (HQ). That means you can wire remote status indication — open/closed, tripped — without adding an external accessory block. Power loss is 13.3 W maximum, so ventilation in a sealed panel is worth checking if you're stacking several breakers.