What it is and what it does
The Siemens 3VA1140-5EF36-0JC0 is a SENTRON molded case circuit breaker (MCCB) with 3 poles, rated for 40 A continuous current at 40 °C. It's built for line protection — meaning it guards feeders and branch circuits against overloads and short circuits, not motor or generator duty. The interrupting ratings climb to 187 kA at 240 V, 121 kA at 415 V, and 75.6 kA at 440 V, so it handles high-fault-current panels without cascading upstream breakers. That 187 kA figure at 240 V is the one that matters for most North American distribution panels; the 121 kA at 415 V covers European 400 V grids. The TM240 overcurrent release is a thermal-magnetic type — fixed thermal curve, magnetic pickup set at 240 A (6x In), so it's a straightforward drop-in for standard feeder protection.
Key ratings and what they mean for fit
Rated continuous current Iu is 40 A, and it holds that rating from 40 °C up to 50 °C without derating. At 55 °C it drops to 38.4 A, then 37.6 A at 60 °C, 36.8 A at 65 °C, and 36 A at 70 °C. If your panel ambient runs hot — say near a drive cabinet or in a non-conditioned enclosure — you need to account for that taper. The rated insulation voltage Ui is 800 V, which covers 480/600 V systems with margin. The breaker carries 2 auxiliary switches (HQ type) for status feedback to a PLC or annunciator; the shunt trip (STL) allows remote tripping from an E-stop or safety relay. No undervoltage release, no ground-fault monitoring, no communication module — this is a plain-vanilla feeder breaker with remote trip capability.
Mounting and panel integration
The breaker measures 76.2 mm wide, 130 mm tall, and 70 mm deep. That 70 mm depth is the dimension from the mounting surface to the front of the breaker — important for enclosure depth planning, especially if you're retrofitting into an existing panel with limited clearance. The 76.2 mm width (3-inch footprint) is standard for a 3-pole MCCB in this class; it fits the usual DIN-rail or panel-mount pattern. Front IP40 protection means it's sealed against tools and small objects but not against dust ingress — fine for a clean indoor panel, not for a washdown area. The reference code per DIN EN 81346-2 is Q, which designates it as a switching device in the functional system.