What this MCCB carries — and what that means for your panel
The Siemens SENTRON 3VA1140-4EF32-0DH0 is a 3-pole molded case circuit breaker rated 40 A continuous current (Iu) with a TM240 thermal-magnetic trip unit. It's a line-protection breaker — no voltage trigger, no ground-fault monitoring, no communication module. What it does have is serious interrupting capacity: 121 kA at 240 V, 75.6 kA at 415 V, and still 52.5 kA at 440 V. That means it can sit upstream of a high-fault panel and clear a bolted fault without the arc flash turning into a fire drill. The 800 V rated insulation voltage (Ui) gives headroom for 480 V or 600 V class systems. The thermal-magnetic curve holds 40 A flat from 40 °C up to 50 °C — no derating needed in a typical warm enclosure. At 55 °C it drops to 38.4 A, and at 70 °C it's still delivering 36 A. If your panel runs hot, you don't lose a full breaker size; you just lose a couple amps. The 15 000 mechanical endurance cycles are standard for this class — not a high-cycle machine-tool breaker, but fine for distribution duty where it operates a few times a year. It ships with an undervoltage release (UVR) and a 2-auxiliary-switch + 1-trip-alarm contact block (HQ type). That means you can wire the UVR into an E-stop chain or a safety relay to drop the breaker on loss of control voltage, and the auxiliary contacts feed status back to a PLC or annunciator. The trip indicator on the front gives a local visual — handy for a maintenance walk-through.
Panel fit and footprint
The 3VA1140-4EF32-0DH0 measures 130 mm high, 76.2 mm wide, 70 mm deep. That's a standard SENTRON 3VA1 frame size — it bolts into the same mounting footprint as the smaller 3VA1010 frame breakers. If you're swapping out a 3VA1010-2ED32-0JA0, the panel cutout and bus-bar spacing are identical; you just get a higher interrupting rating and a different trip curve. The IP40 front face keeps dust out of the mechanism in a clean enclosure; no washdown rating, so keep it behind a gland plate.