40 A MCCB with TM240 release — 187 kA at 240 V
The Siemens SENTRON 3VA1140-5EF36-0JA0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a rated continuous current Iu of 40 A and a rated insulation voltage Ui of 800 V. Its TM240 thermal-magnetic overcurrent release provides fixed thermal and magnetic trip thresholds, sized for the 40 A frame. The interrupting ratings across common voltage levels are substantial: 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 690 V — meaning it can safely clear high-fault currents on industrial distribution without cascading upstream. The breaker includes an integrated shunt trip (STL) design for remote tripping via a voltage trigger, but carries no auxiliary contacts, no undervoltage release, no ground-fault monitoring, and no communication function. It is a straightforward, high-interrupting-capacity main or feeder breaker for panels where remote shunt-trip capability is needed and auxiliary signaling is handled externally.
Thermal derating and panel integration
The 3VA1140-5EF36-0JA0 carries its full 40 A rating from 40 °C through 50 °C ambient. Above that, derating is gradual: 38.4 A at 55 °C, 37.6 A at 60 °C, 36.8 A at 65 °C, and 36 A at 70 °C. For a panel builder sizing a 40 A feeder in a warm enclosure, the margin at 50 °C is comfortable — no upsize needed. The breaker measures 76.2 mm wide, 130 mm high, and 70 mm deep, with IP40 protection on the front. The 70 mm depth is compact enough for standard 200 mm deep enclosures; the 76.2 mm width (roughly 3 inches) fits a 3-pole MCCB footprint common across the SENTRON 3VA platform. Operating temperature range is -25 °C to 70 °C; storage range extends from -40 °C to 80 °C. The part carries a latching endurance of 15,000 cycles, which governs mechanical life under normal switching — not a daily-switch duty class, but adequate for infrequent isolation and fault clearing.