What this MCCB is and what it does
The Siemens 3VA1140-3EF36-0HA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. It carries a rated current of 40 A at 40 °C ambient, with a three-pole configuration and a thermal-magnetic overcurrent release (TM240). The interrupting ratings are 75.6 kA at 240 V, 52.5 kA at 415 V, and 11.9 kA at 690 V, so it handles high fault currents on 400 V class systems without cascading upstream. The rated insulation voltage is 800 V, which covers most industrial voltage levels up to 690 V with margin. This version includes a shunt trip release (STL) for remote tripping — useful in emergency-stop circuits or supervisory shutdown sequences. The supplied basic switch is order code 3VA11403EF360AA0. No undervoltage release, no ground-fault monitoring, no communication function on this variant; it's a straightforward thermal-magnetic breaker with remote-trip capability.
Physical fit and panel integration
The breaker measures 130 mm high, 76.2 mm wide, and 70 mm deep. It mounts on a DIN rail or directly to a backplate via the standard MCCB footprint. The 3-pole width (76.2 mm) is a common 3-module form factor, so it slots into a standard distribution board without extra adapters. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C.
Thermal derating and power loss
Rated current holds at 40 A from 40 °C up to 50 °C, then derates to 39 A at 55–60 °C and 38 A at 65 °C, and 37 A at 70 °C. Maximum power loss is 10.8 W. If the breaker is enclosed in a small, uncooled panel, account for the derating above 50 °C to avoid nuisance tripping.