What it is and what it does
The Siemens 3VA1140-4EF36-0DH0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in three-phase power distribution. Rated 40 A continuous at 40 °C, this 3-pole unit carries a 121 kA interrupting capacity at 240 VAC, dropping to 75.6 kA at 415 V and 52.5 kA at 440 V — numbers that matter when coordinating with upstream gear for selective coordination. The breaker includes an undervoltage release (UVR) and is pre-configured with two auxiliary switches plus one trip alarm switch (HQ), so it's ready for remote status feedback without adding modules.
Breaking capacity across the voltage range
This MCCB's short-circuit rating is voltage-dependent, as you'd expect from a current-limiting design. At 240 VAC it clears 121 kA symmetrical; at 415 VAC that drops to 75.6 kA; at 440 VAC it's 52.5 kA; and at 500 V or 690 VAC it's 11.9 kA. For a 40 A frame, those are high-interrupting ratings — useful when the available fault current at the panelboard is stiff and you need the breaker to hold its own without upstream fuses.
Thermal derating and operating range
Rated 40 A from 40 °C through 50 °C ambient. At 55 °C it derates to 39 A; at 65 °C to 38 A; at 70 °C to 37 A. That's a shallow derating curve — only 3 A lost across a 30 °C rise — so in a warm enclosure you're not giving up much headroom. Operating ambient range is -25 °C to 70 °C; storage from -40 °C to 80 °C. Maximum power loss at rated load is 13.3 W.
Built-in auxiliaries and release
Comes from the factory with two auxiliary switches and one trip alarm switch (HQ) — that's the standard complement for status feedback to a PLC or building management system. The undervoltage release (UVR) is also integrated, so the breaker can be tripped remotely by dropping its control voltage. No communication module on this variant; it's a straightforward line-protection breaker with hardwired signals.
Physical fit and panel integration
Dimensions: 130 mm high, 76.2 mm wide, 70 mm deep. That's a standard 3-pole MCCB footprint for the SENTRON 3VA frame — mounts on a DIN rail or directly to a backplate. The 70 mm depth means it clears most shallow enclosures without a gland-plate conflict. Rated insulation voltage is 800 V, so it's comfortable in 480/277 V or 600 V panels.