What this MCCB is and what the ratings mean for fit
The Siemens SENTRON 3VA1140-5GE46-0AA0 is a 4-pole molded case circuit breaker rated for 40 A continuous current, with a TM220 thermal-magnetic trip unit that provides fixed thermal and magnetic protection for line-feeder or distribution circuits. The 40 A rating holds flat from 40 °C up to 50 °C, then derates to 39 A at 55–60 °C, 38 A at 65 °C, and 37 A at 70 °C — so in a warm panel or enclosure you lose 3 A at the top end. The breaking capacity tells you where it can safely interrupt a fault: 187 kA at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at both 500 V and 690 V. That 187 kA at 240 V is a high-interrupting rating, typical for large service-entrance or distribution panels where available fault current is significant. The rated insulation voltage is 800 V, which means the internal clearances and creepage distances are designed for 690 V systems with margin.
Deployment context and panel integration
This MCCB mounts on a DIN rail or directly to a backplate in a distribution panel or motor control center. The front face carries an IP40 protection class, meaning it is protected against tools and wires greater than 1 mm — fine for a dry indoor panel, but not rated for washdown or outdoor exposure. Dimensions are 130 mm height, 101.6 mm width, 70 mm depth — a 4-pole footprint that fits standard Siemens SENTRON panel cutouts. The TM220 trip unit is non-interchangeable, so the protection curve is fixed at the factory; no field-swap of trip modules.
What the TM220 trip unit means for protection
The TM220 designation indicates a thermal-magnetic trip with fixed settings: the thermal element (for overload protection) is calibrated to the 40 A rating, and the magnetic element (for short-circuit protection) has a fixed pickup. There is no ground-fault monitoring version, no undervoltage release, and no communication function — this is a basic, no-frills line-protection breaker. The maximum power loss is 10.8 W, which matters for heat buildup in a sealed enclosure. Storage temperature range is -40 °C to 80 °C; operating range is -25 °C to 70 °C.