What this MCCB carries and where it fits
The Siemens 3VA1140-4EF36-0AH0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. It is a 3-pole unit rated 40 A continuously at 40 °C, with a TM240 thermal-magnetic overcurrent release — meaning the thermal element handles overloads and the magnetic element clears short-circuits up to its rated breaking capacity. The 121 kA interrupting rating at 240 VAC gives it headroom on high-fault utility feeds or transformer secondaries; at 415 VAC it still clears 75.6 kA, and at 690 VAC it holds 11.9 kA. That SCCR range makes it suitable for panel main or feeder duty where fault current is substantial. Rated insulation voltage is 800 V, so the breaker is rated for 690 VAC line-to-line systems. The housing is sized at 130 mm high × 76.2 mm wide × 70 mm deep — a standard SENTRON 3VA fixed-mount footprint that fits the same panel cutout as other 3VA1140 frame sizes. Maximum power loss at rated load is 10.8 W, which matters for thermal management in a sealed enclosure.
Auxiliary switching and monitoring
This variant ships with 2 auxiliary switches plus 1 trip alarm switch (HQ configuration). The auxiliary contacts follow the breaker position (ON/OFF); the trip alarm switch closes only on a fault trip, which gives a separate signal for remote annunciation without needing an external relay. There is no undervoltage release, no ground-fault monitoring, and no communication module on this order code — it is a straight line-protection MCCB with local indication only. The trip indicator flag on the front confirms whether the breaker opened on overload/short or was manually switched off.
Thermal derating and operating range
The 40 A rating holds from 40 °C up to 50 °C without derating. At 55 °C it drops 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; storage range is -40 °C to +80 °C. If the breaker sits in a hot panel near other heat sources, use the 65 °C or 70 °C column for the continuous current limit — not the 40 °C nameplate.