What it is and what the ratings mean
The Siemens 3VA1140-5EF32-0DH0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. It's a 3-pole unit rated 40 A continuous at 40 °C, with an interrupting capacity of 187 kA at 240 V — that's the fault current it can safely clear without welding contacts or rupturing the case, so it's sized for high-fault locations like service entrances or industrial switchboards where available fault current is substantial. The interrupting rating drops as voltage rises: 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 500 V and 690 V. That's typical for an MCCB — the arc energy scales with voltage, so the same breaker can't interrupt as much current at higher potentials. For a 480 V panel, the 75.6 kA figure is the one that governs SCCR coordination. Thermal derating is mild: it holds 40 A up to 50 °C, then drops to 39 A at 55–60 °C, 38 A at 65 °C, and 37 A at 70 °C. That means in a hot enclosure near the top of a panel, you still get nearly full rating — no need to oversize for ambient.
Built-in accessories and integration
This variant ships with an undervoltage release (UVR) and a complement of auxiliary switches: 2 auxiliary switches plus 1 trip alarm switch (HQ). The UVR means the breaker trips if control voltage drops — common for emergency-stop circuits or undervoltage protection on motor feeders. The auxiliary switches give status feedback to a PLC or annunciator without needing external contact blocks. Dimensions are 70 mm deep, 76.2 mm wide, 130 mm tall — a standard 3-pole MCCB footprint that fits SENTRON panelboards and most DIN-rail adapters. The insulation voltage is rated 800 V, so it's suitable for 690 V systems with margin.
Lifecycle and sourcing
Power loss is 13.3 W maximum at rated load — useful for thermal calculations in a sealed enclosure. The operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C.